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2023-08-30tracing: Fix memleak due to race between current_tracer and traceZheng Yejian
[ Upstream commit eecb91b9f98d6427d4af5fdb8f108f52572a39e7 ] Kmemleak report a leak in graph_trace_open(): unreferenced object 0xffff0040b95f4a00 (size 128): comm "cat", pid 204981, jiffies 4301155872 (age 99771.964s) hex dump (first 32 bytes): e0 05 e7 b4 ab 7d 00 00 0b 00 01 00 00 00 00 00 .....}.......... f4 00 01 10 00 a0 ff ff 00 00 00 00 65 00 10 00 ............e... backtrace: [<000000005db27c8b>] kmem_cache_alloc_trace+0x348/0x5f0 [<000000007df90faa>] graph_trace_open+0xb0/0x344 [<00000000737524cd>] __tracing_open+0x450/0xb10 [<0000000098043327>] tracing_open+0x1a0/0x2a0 [<00000000291c3876>] do_dentry_open+0x3c0/0xdc0 [<000000004015bcd6>] vfs_open+0x98/0xd0 [<000000002b5f60c9>] do_open+0x520/0x8d0 [<00000000376c7820>] path_openat+0x1c0/0x3e0 [<00000000336a54b5>] do_filp_open+0x14c/0x324 [<000000002802df13>] do_sys_openat2+0x2c4/0x530 [<0000000094eea458>] __arm64_sys_openat+0x130/0x1c4 [<00000000a71d7881>] el0_svc_common.constprop.0+0xfc/0x394 [<00000000313647bf>] do_el0_svc+0xac/0xec [<000000002ef1c651>] el0_svc+0x20/0x30 [<000000002fd4692a>] el0_sync_handler+0xb0/0xb4 [<000000000c309c35>] el0_sync+0x160/0x180 The root cause is descripted as follows: __tracing_open() { // 1. File 'trace' is being opened; ... *iter->trace = *tr->current_trace; // 2. Tracer 'function_graph' is // currently set; ... iter->trace->open(iter); // 3. Call graph_trace_open() here, // and memory are allocated in it; ... } s_start() { // 4. The opened file is being read; ... *iter->trace = *tr->current_trace; // 5. If tracer is switched to // 'nop' or others, then memory // in step 3 are leaked!!! ... } To fix it, in s_start(), close tracer before switching then reopen the new tracer after switching. And some tracers like 'wakeup' may not update 'iter->private' in some cases when reopen, then it should be cleared to avoid being mistakenly closed again. Link: https://lore.kernel.org/linux-trace-kernel/20230817125539.1646321-1-zhengyejian1@huawei.com Fixes: d7350c3f4569 ("tracing/core: make the read callbacks reentrants") Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-30tracing/synthetic: Allocate one additional element for sizeSven Schnelle
[ Upstream commit c4d6b5438116c184027b2e911c0f2c7c406fb47c ] While debugging another issue I noticed that the stack trace contains one invalid entry at the end: <idle>-0 [008] d..4. 26.484201: wake_lat: pid=0 delta=2629976084 000000009cc24024 stack=STACK: => __schedule+0xac6/0x1a98 => schedule+0x126/0x2c0 => schedule_timeout+0x150/0x2c0 => kcompactd+0x9ca/0xc20 => kthread+0x2f6/0x3d8 => __ret_from_fork+0x8a/0xe8 => 0x6b6b6b6b6b6b6b6b This is because the code failed to add the one element containing the number of entries to field_size. Link: https://lkml.kernel.org/r/20230816154928.4171614-4-svens@linux.ibm.com Cc: Masami Hiramatsu <mhiramat@kernel.org> Fixes: 00cf3d672a9d ("tracing: Allow synthetic events to pass around stacktraces") Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-30tracing/synthetic: Skip first entry for stack tracesSven Schnelle
[ Upstream commit 887f92e09ef34a949745ad26ce82be69e2dabcf6 ] While debugging another issue I noticed that the stack trace output contains the number of entries on top: <idle>-0 [000] d..4. 203.322502: wake_lat: pid=0 delta=2268270616 stack=STACK: => 0x10 => __schedule+0xac6/0x1a98 => schedule+0x126/0x2c0 => schedule_timeout+0x242/0x2c0 => __wait_for_common+0x434/0x680 => __wait_rcu_gp+0x198/0x3e0 => synchronize_rcu+0x112/0x138 => ring_buffer_reset_online_cpus+0x140/0x2e0 => tracing_reset_online_cpus+0x15c/0x1d0 => tracing_set_clock+0x180/0x1d8 => hist_register_trigger+0x486/0x670 => event_hist_trigger_parse+0x494/0x1318 => trigger_process_regex+0x1d4/0x258 => event_trigger_write+0xb4/0x170 => vfs_write+0x210/0xad0 => ksys_write+0x122/0x208 Fix this by skipping the first element. Also replace the pointer logic with an index variable which is easier to read. Link: https://lkml.kernel.org/r/20230816154928.4171614-3-svens@linux.ibm.com Cc: Masami Hiramatsu <mhiramat@kernel.org> Fixes: 00cf3d672a9d ("tracing: Allow synthetic events to pass around stacktraces") Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-30tracing/synthetic: Use union instead of castsSven Schnelle
[ Upstream commit ddeea494a16f32522bce16ee65f191d05d4b8282 ] The current code uses a lot of casts to access the fields member in struct synth_trace_events with different sizes. This makes the code hard to read, and had already introduced an endianness bug. Use a union and struct instead. Link: https://lkml.kernel.org/r/20230816154928.4171614-2-svens@linux.ibm.com Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Fixes: 00cf3d672a9dd ("tracing: Allow synthetic events to pass around stacktraces") Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Stable-dep-of: 887f92e09ef3 ("tracing/synthetic: Skip first entry for stack traces") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-30tracing: Fix cpu buffers unavailable due to 'record_disabled' missedZheng Yejian
[ Upstream commit b71645d6af10196c46cbe3732de2ea7d36b3ff6d ] Trace ring buffer can no longer record anything after executing following commands at the shell prompt: # cd /sys/kernel/tracing # cat tracing_cpumask fff # echo 0 > tracing_cpumask # echo 1 > snapshot # echo fff > tracing_cpumask # echo 1 > tracing_on # echo "hello world" > trace_marker -bash: echo: write error: Bad file descriptor The root cause is that: 1. After `echo 0 > tracing_cpumask`, 'record_disabled' of cpu buffers in 'tr->array_buffer.buffer' became 1 (see tracing_set_cpumask()); 2. After `echo 1 > snapshot`, 'tr->array_buffer.buffer' is swapped with 'tr->max_buffer.buffer', then the 'record_disabled' became 0 (see update_max_tr()); 3. After `echo fff > tracing_cpumask`, the 'record_disabled' become -1; Then array_buffer and max_buffer are both unavailable due to value of 'record_disabled' is not 0. To fix it, enable or disable both array_buffer and max_buffer at the same time in tracing_set_cpumask(). Link: https://lkml.kernel.org/r/20230805033816.3284594-2-zhengyejian1@huawei.com Cc: <mhiramat@kernel.org> Cc: <vnagarnaik@google.com> Cc: <shuah@kernel.org> Fixes: 71babb2705e2 ("tracing: change CPU ring buffer state from tracing_cpumask") Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-23ring-buffer: Do not swap cpu_buffer during resize processChen Lin
[ Upstream commit 8a96c0288d0737ad77882024974c075345c72011 ] When ring_buffer_swap_cpu was called during resize process, the cpu buffer was swapped in the middle, resulting in incorrect state. Continuing to run in the wrong state will result in oops. This issue can be easily reproduced using the following two scripts: /tmp # cat test1.sh //#! /bin/sh for i in `seq 0 100000` do echo 2000 > /sys/kernel/debug/tracing/buffer_size_kb sleep 0.5 echo 5000 > /sys/kernel/debug/tracing/buffer_size_kb sleep 0.5 done /tmp # cat test2.sh //#! /bin/sh for i in `seq 0 100000` do echo irqsoff > /sys/kernel/debug/tracing/current_tracer sleep 1 echo nop > /sys/kernel/debug/tracing/current_tracer sleep 1 done /tmp # ./test1.sh & /tmp # ./test2.sh & A typical oops log is as follows, sometimes with other different oops logs. [ 231.711293] WARNING: CPU: 0 PID: 9 at kernel/trace/ring_buffer.c:2026 rb_update_pages+0x378/0x3f8 [ 231.713375] Modules linked in: [ 231.714735] CPU: 0 PID: 9 Comm: kworker/0:1 Tainted: G W 6.5.0-rc1-00276-g20edcec23f92 #15 [ 231.716750] Hardware name: linux,dummy-virt (DT) [ 231.718152] Workqueue: events update_pages_handler [ 231.719714] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 231.721171] pc : rb_update_pages+0x378/0x3f8 [ 231.722212] lr : rb_update_pages+0x25c/0x3f8 [ 231.723248] sp : ffff800082b9bd50 [ 231.724169] x29: ffff800082b9bd50 x28: ffff8000825f7000 x27: 0000000000000000 [ 231.726102] x26: 0000000000000001 x25: fffffffffffff010 x24: 0000000000000ff0 [ 231.728122] x23: ffff0000c3a0b600 x22: ffff0000c3a0b5c0 x21: fffffffffffffe0a [ 231.730203] x20: ffff0000c3a0b600 x19: ffff0000c0102400 x18: 0000000000000000 [ 231.732329] x17: 0000000000000000 x16: 0000000000000000 x15: 0000ffffe7aa8510 [ 231.734212] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000002 [ 231.736291] x11: ffff8000826998a8 x10: ffff800082b9baf0 x9 : ffff800081137558 [ 231.738195] x8 : fffffc00030e82c8 x7 : 0000000000000000 x6 : 0000000000000001 [ 231.740192] x5 : ffff0000ffbafe00 x4 : 0000000000000000 x3 : 0000000000000000 [ 231.742118] x2 : 00000000000006aa x1 : 0000000000000001 x0 : ffff0000c0007208 [ 231.744196] Call trace: [ 231.744892] rb_update_pages+0x378/0x3f8 [ 231.745893] update_pages_handler+0x1c/0x38 [ 231.746893] process_one_work+0x1f0/0x468 [ 231.747852] worker_thread+0x54/0x410 [ 231.748737] kthread+0x124/0x138 [ 231.749549] ret_from_fork+0x10/0x20 [ 231.750434] ---[ end trace 0000000000000000 ]--- [ 233.720486] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [ 233.721696] Mem abort info: [ 233.721935] ESR = 0x0000000096000004 [ 233.722283] EC = 0x25: DABT (current EL), IL = 32 bits [ 233.722596] SET = 0, FnV = 0 [ 233.722805] EA = 0, S1PTW = 0 [ 233.723026] FSC = 0x04: level 0 translation fault [ 233.723458] Data abort info: [ 233.723734] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 [ 233.724176] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 [ 233.724589] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 233.725075] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000104943000 [ 233.725592] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 [ 233.726231] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP [ 233.726720] Modules linked in: [ 233.727007] CPU: 0 PID: 9 Comm: kworker/0:1 Tainted: G W 6.5.0-rc1-00276-g20edcec23f92 #15 [ 233.727777] Hardware name: linux,dummy-virt (DT) [ 233.728225] Workqueue: events update_pages_handler [ 233.728655] pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 233.729054] pc : rb_update_pages+0x1a8/0x3f8 [ 233.729334] lr : rb_update_pages+0x154/0x3f8 [ 233.729592] sp : ffff800082b9bd50 [ 233.729792] x29: ffff800082b9bd50 x28: ffff8000825f7000 x27: 0000000000000000 [ 233.730220] x26: 0000000000000000 x25: ffff800082a8b840 x24: ffff0000c0102418 [ 233.730653] x23: 0000000000000000 x22: fffffc000304c880 x21: 0000000000000003 [ 233.731105] x20: 00000000000001f4 x19: ffff0000c0102400 x18: ffff800082fcbc58 [ 233.731727] x17: 0000000000000000 x16: 0000000000000001 x15: 0000000000000001 [ 233.732282] x14: ffff8000825fe0c8 x13: 0000000000000001 x12: 0000000000000000 [ 233.732709] x11: ffff8000826998a8 x10: 0000000000000ae0 x9 : ffff8000801b760c [ 233.733148] x8 : fefefefefefefeff x7 : 0000000000000018 x6 : ffff0000c03298c0 [ 233.733553] x5 : 0000000000000002 x4 : 0000000000000000 x3 : 0000000000000000 [ 233.733972] x2 : ffff0000c3a0b600 x1 : 0000000000000000 x0 : 0000000000000000 [ 233.734418] Call trace: [ 233.734593] rb_update_pages+0x1a8/0x3f8 [ 233.734853] update_pages_handler+0x1c/0x38 [ 233.735148] process_one_work+0x1f0/0x468 [ 233.735525] worker_thread+0x54/0x410 [ 233.735852] kthread+0x124/0x138 [ 233.736064] ret_from_fork+0x10/0x20 [ 233.736387] Code: 92400000 910006b5 aa000021 aa0303f7 (f9400060) [ 233.736959] ---[ end trace 0000000000000000 ]--- After analysis, the seq of the error is as follows [1-5]: int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, int cpu_id) { for_each_buffer_cpu(buffer, cpu) { cpu_buffer = buffer->buffers[cpu]; //1. get cpu_buffer, aka cpu_buffer(A) ... ... schedule_work_on(cpu, &cpu_buffer->update_pages_work); //2. 'update_pages_work' is queue on 'cpu', cpu_buffer(A) is passed to // update_pages_handler, do the update process, set 'update_done' in // complete(&cpu_buffer->update_done) and to wakeup resize process. //----> //3. Just at this moment, ring_buffer_swap_cpu is triggered, //cpu_buffer(A) be swaped to cpu_buffer(B), the max_buffer. //ring_buffer_swap_cpu is called as the 'Call trace' below. Call trace: dump_backtrace+0x0/0x2f8 show_stack+0x18/0x28 dump_stack+0x12c/0x188 ring_buffer_swap_cpu+0x2f8/0x328 update_max_tr_single+0x180/0x210 check_critical_timing+0x2b4/0x2c8 tracer_hardirqs_on+0x1c0/0x200 trace_hardirqs_on+0xec/0x378 el0_svc_common+0x64/0x260 do_el0_svc+0x90/0xf8 el0_svc+0x20/0x30 el0_sync_handler+0xb0/0xb8 el0_sync+0x180/0x1c0 //<---- /* wait for all the updates to complete */ for_each_buffer_cpu(buffer, cpu) { cpu_buffer = buffer->buffers[cpu]; //4. get cpu_buffer, cpu_buffer(B) is used in the following process, //the state of cpu_buffer(A) and cpu_buffer(B) is totally wrong. //for example, cpu_buffer(A)->update_done will leave be set 1, and will //not 'wait_for_completion' at the next resize round. if (!cpu_buffer->nr_pages_to_update) continue; if (cpu_online(cpu)) wait_for_completion(&cpu_buffer->update_done); cpu_buffer->nr_pages_to_update = 0; } ... } //5. the state of cpu_buffer(A) and cpu_buffer(B) is totally wrong, //Continuing to run in the wrong state, then oops occurs. Link: https://lore.kernel.org/linux-trace-kernel/202307191558478409990@zte.com.cn Signed-off-by: Chen Lin <chen.lin5@zte.com.cn> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-11bpf: Disable preemption in bpf_event_outputJiri Olsa
commit d62cc390c2e99ae267ffe4b8d7e2e08b6c758c32 upstream. We received report [1] of kernel crash, which is caused by using nesting protection without disabled preemption. The bpf_event_output can be called by programs executed by bpf_prog_run_array_cg function that disabled migration but keeps preemption enabled. This can cause task to be preempted by another one inside the nesting protection and lead eventually to two tasks using same perf_sample_data buffer and cause crashes like: BUG: kernel NULL pointer dereference, address: 0000000000000001 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0010) - not-present page ... ? perf_output_sample+0x12a/0x9a0 ? finish_task_switch.isra.0+0x81/0x280 ? perf_event_output+0x66/0xa0 ? bpf_event_output+0x13a/0x190 ? bpf_event_output_data+0x22/0x40 ? bpf_prog_dfc84bbde731b257_cil_sock4_connect+0x40a/0xacb ? xa_load+0x87/0xe0 ? __cgroup_bpf_run_filter_sock_addr+0xc1/0x1a0 ? release_sock+0x3e/0x90 ? sk_setsockopt+0x1a1/0x12f0 ? udp_pre_connect+0x36/0x50 ? inet_dgram_connect+0x93/0xa0 ? __sys_connect+0xb4/0xe0 ? udp_setsockopt+0x27/0x40 ? __pfx_udp_push_pending_frames+0x10/0x10 ? __sys_setsockopt+0xdf/0x1a0 ? __x64_sys_connect+0xf/0x20 ? do_syscall_64+0x3a/0x90 ? entry_SYSCALL_64_after_hwframe+0x72/0xdc Fixing this by disabling preemption in bpf_event_output. [1] https://github.com/cilium/cilium/issues/26756 Cc: stable@vger.kernel.org Reported-by: Oleg "livelace" Popov <o.popov@livelace.ru> Closes: https://github.com/cilium/cilium/issues/26756 Fixes: 2a916f2f546c ("bpf: Use migrate_disable/enable in array macros and cgroup/lirc code.") Acked-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20230725084206.580930-3-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-11bpf: Disable preemption in bpf_perf_event_outputJiri Olsa
commit f2c67a3e60d1071b65848efaa8c3b66c363dd025 upstream. The nesting protection in bpf_perf_event_output relies on disabled preemption, which is guaranteed for kprobes and tracepoints. However bpf_perf_event_output can be also called from uprobes context through bpf_prog_run_array_sleepable function which disables migration, but keeps preemption enabled. This can cause task to be preempted by another one inside the nesting protection and lead eventually to two tasks using same perf_sample_data buffer and cause crashes like: kernel tried to execute NX-protected page - exploit attempt? (uid: 0) BUG: unable to handle page fault for address: ffffffff82be3eea ... Call Trace: ? __die+0x1f/0x70 ? page_fault_oops+0x176/0x4d0 ? exc_page_fault+0x132/0x230 ? asm_exc_page_fault+0x22/0x30 ? perf_output_sample+0x12b/0x910 ? perf_event_output+0xd0/0x1d0 ? bpf_perf_event_output+0x162/0x1d0 ? bpf_prog_c6271286d9a4c938_krava1+0x76/0x87 ? __uprobe_perf_func+0x12b/0x540 ? uprobe_dispatcher+0x2c4/0x430 ? uprobe_notify_resume+0x2da/0xce0 ? atomic_notifier_call_chain+0x7b/0x110 ? exit_to_user_mode_prepare+0x13e/0x290 ? irqentry_exit_to_user_mode+0x5/0x30 ? asm_exc_int3+0x35/0x40 Fixing this by disabling preemption in bpf_perf_event_output. Cc: stable@vger.kernel.org Fixes: 8c7dcb84e3b7 ("bpf: implement sleepable uprobes by chaining gps") Acked-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20230725084206.580930-2-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-03tracing: Fix warning in trace_buffered_event_disable()Zheng Yejian
[ Upstream commit dea499781a1150d285c62b26659f62fb00824fce ] Warning happened in trace_buffered_event_disable() at WARN_ON_ONCE(!trace_buffered_event_ref) Call Trace: ? __warn+0xa5/0x1b0 ? trace_buffered_event_disable+0x189/0x1b0 __ftrace_event_enable_disable+0x19e/0x3e0 free_probe_data+0x3b/0xa0 unregister_ftrace_function_probe_func+0x6b8/0x800 event_enable_func+0x2f0/0x3d0 ftrace_process_regex.isra.0+0x12d/0x1b0 ftrace_filter_write+0xe6/0x140 vfs_write+0x1c9/0x6f0 [...] The cause of the warning is in __ftrace_event_enable_disable(), trace_buffered_event_enable() was called once while trace_buffered_event_disable() was called twice. Reproduction script show as below, for analysis, see the comments: ``` #!/bin/bash cd /sys/kernel/tracing/ # 1. Register a 'disable_event' command, then: # 1) SOFT_DISABLED_BIT was set; # 2) trace_buffered_event_enable() was called first time; echo 'cmdline_proc_show:disable_event:initcall:initcall_finish' > \ set_ftrace_filter # 2. Enable the event registered, then: # 1) SOFT_DISABLED_BIT was cleared; # 2) trace_buffered_event_disable() was called first time; echo 1 > events/initcall/initcall_finish/enable # 3. Try to call into cmdline_proc_show(), then SOFT_DISABLED_BIT was # set again!!! cat /proc/cmdline # 4. Unregister the 'disable_event' command, then: # 1) SOFT_DISABLED_BIT was cleared again; # 2) trace_buffered_event_disable() was called second time!!! echo '!cmdline_proc_show:disable_event:initcall:initcall_finish' > \ set_ftrace_filter ``` To fix it, IIUC, we can change to call trace_buffered_event_enable() at fist time soft-mode enabled, and call trace_buffered_event_disable() at last time soft-mode disabled. Link: https://lore.kernel.org/linux-trace-kernel/20230726095804.920457-1-zhengyejian1@huawei.com Cc: <mhiramat@kernel.org> Fixes: 0fc1b09ff1ff ("tracing: Use temp buffer when filtering events") Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-03ring-buffer: Fix wrong stat of cpu_buffer->readZheng Yejian
[ Upstream commit 2d093282b0d4357373497f65db6a05eb0c28b7c8 ] When pages are removed in rb_remove_pages(), 'cpu_buffer->read' is set to 0 in order to make sure any read iterators reset themselves. However, this will mess 'entries' stating, see following steps: # cd /sys/kernel/tracing/ # 1. Enlarge ring buffer prepare for later reducing: # echo 20 > per_cpu/cpu0/buffer_size_kb # 2. Write a log into ring buffer of cpu0: # taskset -c 0 echo "hello1" > trace_marker # 3. Read the log: # cat per_cpu/cpu0/trace_pipe <...>-332 [000] ..... 62.406844: tracing_mark_write: hello1 # 4. Stop reading and see the stats, now 0 entries, and 1 event readed: # cat per_cpu/cpu0/stats entries: 0 [...] read events: 1 # 5. Reduce the ring buffer # echo 7 > per_cpu/cpu0/buffer_size_kb # 6. Now entries became unexpected 1 because actually no entries!!! # cat per_cpu/cpu0/stats entries: 1 [...] read events: 0 To fix it, introduce 'page_removed' field to count total removed pages since last reset, then use it to let read iterators reset themselves instead of changing the 'read' pointer. Link: https://lore.kernel.org/linux-trace-kernel/20230724054040.3489499-1-zhengyejian1@huawei.com Cc: <mhiramat@kernel.org> Cc: <vnagarnaik@google.com> Fixes: 83f40318dab0 ("ring-buffer: Make removal of ring buffer pages atomic") Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-27tracing/histograms: Return an error if we fail to add histogram to hist_vars ↵Mohamed Khalfella
list commit 4b8b3905165ef98386a3c06f196c85d21292d029 upstream. Commit 6018b585e8c6 ("tracing/histograms: Add histograms to hist_vars if they have referenced variables") added a check to fail histogram creation if save_hist_vars() failed to add histogram to hist_vars list. But the commit failed to set ret to failed return code before jumping to unregister histogram, fix it. Link: https://lore.kernel.org/linux-trace-kernel/20230714203341.51396-1-mkhalfella@purestorage.com Cc: stable@vger.kernel.org Fixes: 6018b585e8c6 ("tracing/histograms: Add histograms to hist_vars if they have referenced variables") Signed-off-by: Mohamed Khalfella <mkhalfella@purestorage.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-23tracing/user_events: Fix struct arg size match checkBeau Belgrave
commit d0a3022f30629a208e5944022caeca3568add9e7 upstream. When users register an event the name of the event and it's argument are checked to ensure they match if the event already exists. Normally all arguments are in the form of "type name", except for when the type starts with "struct ". In those cases, the size of the struct is passed in addition to the name, IE: "struct my_struct a 20" for an argument that is of type "struct my_struct" with a field name of "a" and has the size of 20 bytes. The current code does not honor the above case properly when comparing a match. This causes the event register to fail even when the same string was used for events that contain a struct argument within them. The example above "struct my_struct a 20" generates a match string of "struct my_struct a" omitting the size field. Add the struct size of the existing field when generating a comparison string for a struct field to ensure proper match checking. Link: https://lkml.kernel.org/r/20230629235049.581-2-beaub@linux.microsoft.com Cc: stable@vger.kernel.org Fixes: e6f89a149872 ("tracing/user_events: Ensure user provided strings are safely formatted") Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-23tracing/probes: Fix to record 0-length data_loc in fetch_store_string*() if ↵Masami Hiramatsu (Google)
fails commit 797311bce5c2ac90b8d65e357603cfd410d36ebb upstream. Fix to record 0-length data to data_loc in fetch_store_string*() if it fails to get the string data. Currently those expect that the data_loc is updated by store_trace_args() if it returns the error code. However, that does not work correctly if the argument is an array of strings. In that case, store_trace_args() only clears the first entry of the array (which may have no error) and leaves other entries. So it should be cleared by fetch_store_string*() itself. Also, 'dyndata' and 'maxlen' in store_trace_args() should be updated only if it is used (ret > 0 and argument is a dynamic data.) Link: https://lore.kernel.org/all/168908496683.123124.4761206188794205601.stgit@devnote2/ Fixes: 40b53b771806 ("tracing: probeevent: Add array type support") Cc: stable@vger.kernel.org Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-23Revert "tracing: Add "(fault)" name injection to kernel probes"Masami Hiramatsu (Google)
commit 4ed8f337dee32df71435689c19d22e4ee846e15a upstream. This reverts commit 2e9906f84fc7c99388bb7123ade167250d50f1c0. It was turned out that commit 2e9906f84fc7 ("tracing: Add "(fault)" name injection to kernel probes") did not work correctly and probe events still show just '(fault)' (instead of '"(fault)"'). Also, current '(fault)' is more explicit that it faulted. This also moves FAULT_STRING macro to trace.h so that synthetic event can keep using it, and uses it in trace_probe.c too. Link: https://lore.kernel.org/all/168908495772.123124.1250788051922100079.stgit@devnote2/ Link: https://lore.kernel.org/all/20230706230642.3793a593@rorschach.local.home/ Cc: stable@vger.kernel.org Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-23tracing/probes: Fix to update dynamic data counter if fetcharg uses itMasami Hiramatsu (Google)
commit e38e2c6a9efc435f9de344b7c91f7697e01b47d5 upstream. Fix to update dynamic data counter ('dyndata') and max length ('maxlen') only if the fetcharg uses the dynamic data. Also get out arg->dynamic from unlikely(). This makes dynamic data address wrong if process_fetch_insn() returns error on !arg->dynamic case. Link: https://lore.kernel.org/all/168908494781.123124.8160245359962103684.stgit@devnote2/ Suggested-by: Steven Rostedt <rostedt@goodmis.org> Link: https://lore.kernel.org/all/20230710233400.5aaf024e@gandalf.local.home/ Fixes: 9178412ddf5a ("tracing: probeevent: Return consumed bytes of dynamic area") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-23tracing/probes: Fix not to count error code to total lengthMasami Hiramatsu (Google)
commit b41326b5e0f82e93592c4366359917b5d67b529f upstream. Fix not to count the error code (which is minus value) to the total used length of array, because it can mess up the return code of process_fetch_insn_bottom(). Also clear the 'ret' value because it will be used for calculating next data_loc entry. Link: https://lore.kernel.org/all/168908493827.123124.2175257289106364229.stgit@devnote2/ Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Closes: https://lore.kernel.org/all/8819b154-2ba1-43c3-98a2-cbde20892023@moroto.mountain/ Fixes: 9b960a38835f ("tracing: probeevent: Unify fetch_insn processing common part") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-23tracing/probes: Fix to avoid double count of the string length on the arrayMasami Hiramatsu (Google)
commit 66bcf65d6cf0ca6540e2341e88ee7ef02dbdda08 upstream. If an array is specified with the ustring or symstr, the length of the strings are accumlated on both of 'ret' and 'total', which means the length is double counted. Just set the length to the 'ret' value for avoiding double counting. Link: https://lore.kernel.org/all/168908492917.123124.15076463491122036025.stgit@devnote2/ Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Closes: https://lore.kernel.org/all/8819b154-2ba1-43c3-98a2-cbde20892023@moroto.mountain/ Fixes: 88903c464321 ("tracing/probe: Add ustring type for user-space string") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-23tracing: Fix null pointer dereference in tracing_err_log_open()Mateusz Stachyra
commit 02b0095e2fbbc060560c1065f86a211d91e27b26 upstream. Fix an issue in function 'tracing_err_log_open'. The function doesn't call 'seq_open' if the file is opened only with write permissions, which results in 'file->private_data' being left as null. If we then use 'lseek' on that opened file, 'seq_lseek' dereferences 'file->private_data' in 'mutex_lock(&m->lock)', resulting in a kernel panic. Writing to this node requires root privileges, therefore this bug has very little security impact. Tracefs node: /sys/kernel/tracing/error_log Example Kernel panic: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000038 Call trace: mutex_lock+0x30/0x110 seq_lseek+0x34/0xb8 __arm64_sys_lseek+0x6c/0xb8 invoke_syscall+0x58/0x13c el0_svc_common+0xc4/0x10c do_el0_svc+0x24/0x98 el0_svc+0x24/0x88 el0t_64_sync_handler+0x84/0xe4 el0t_64_sync+0x1b4/0x1b8 Code: d503201f aa0803e0 aa1f03e1 aa0103e9 (c8e97d02) ---[ end trace 561d1b49c12cf8a5 ]--- Kernel panic - not syncing: Oops: Fatal exception Link: https://lore.kernel.org/linux-trace-kernel/20230703155237eucms1p4dfb6a19caa14c79eb6c823d127b39024@eucms1p4 Link: https://lore.kernel.org/linux-trace-kernel/20230704102706eucms1p30d7ecdcc287f46ad67679fc8491b2e0f@eucms1p3 Cc: stable@vger.kernel.org Fixes: 8a062902be725 ("tracing: Add tracing error log") Signed-off-by: Mateusz Stachyra <m.stachyra@samsung.com> Suggested-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-23fprobe: Ensure running fprobe_exit_handler() finished before calling ↵Masami Hiramatsu (Google)
rethook_free() commit 195b9cb5b288fec1c871ef89f78cc9a7461aad3a upstream. Ensure running fprobe_exit_handler() has finished before calling rethook_free() in the unregister_fprobe() so that caller can free the fprobe right after unregister_fprobe(). unregister_fprobe() ensured that all running fprobe_entry/exit_handler() have finished by calling unregister_ftrace_function() which synchronizes RCU. But commit 5f81018753df ("fprobe: Release rethook after the ftrace_ops is unregistered") changed to call rethook_free() after unregister_ftrace_function(). So call rethook_stop() to make rethook disabled before unregister_ftrace_function() and ensure it again. Here is the possible code flow that can call the exit handler after unregister_fprobe(). ------ CPU1 CPU2 call unregister_fprobe(fp) ... __fprobe_handler() rethook_hook() on probed function unregister_ftrace_function() return from probed function rethook hooks find rh->handler == fprobe_exit_handler call fprobe_exit_handler() rethook_free(): set rh->handler = NULL; return from unreigster_fprobe; call fp->exit_handler() <- (*) ------ (*) At this point, the exit handler is called after returning from unregister_fprobe(). This fixes it as following; ------ CPU1 CPU2 call unregister_fprobe() ... rethook_stop(): set rh->handler = NULL; __fprobe_handler() rethook_hook() on probed function unregister_ftrace_function() return from probed function rethook hooks find rh->handler == NULL return from rethook rethook_free() return from unreigster_fprobe; ------ Link: https://lore.kernel.org/all/168873859949.156157.13039240432299335849.stgit@devnote2/ Fixes: 5f81018753df ("fprobe: Release rethook after the ftrace_ops is unregistered") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-23fprobe: Release rethook after the ftrace_ops is unregisteredJiri Olsa
commit 5f81018753dfd4989e33ece1f0cb6b8aae498b82 upstream. While running bpf selftests it's possible to get following fault: general protection fault, probably for non-canonical address \ 0x6b6b6b6b6b6b6b6b: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC NOPTI ... Call Trace: <TASK> fprobe_handler+0xc1/0x270 ? __pfx_bpf_testmod_init+0x10/0x10 ? __pfx_bpf_testmod_init+0x10/0x10 ? bpf_fentry_test1+0x5/0x10 ? bpf_fentry_test1+0x5/0x10 ? bpf_testmod_init+0x22/0x80 ? do_one_initcall+0x63/0x2e0 ? rcu_is_watching+0xd/0x40 ? kmalloc_trace+0xaf/0xc0 ? do_init_module+0x60/0x250 ? __do_sys_finit_module+0xac/0x120 ? do_syscall_64+0x37/0x90 ? entry_SYSCALL_64_after_hwframe+0x72/0xdc </TASK> In unregister_fprobe function we can't release fp->rethook while it's possible there are some of its users still running on another cpu. Moving rethook_free call after fp->ops is unregistered with unregister_ftrace_function call. Link: https://lore.kernel.org/all/20230615115236.3476617-1-jolsa@kernel.org/ Fixes: 5b0ab78998e3 ("fprobe: Add exit_handler support") Cc: stable@vger.kernel.org Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-23ftrace: Fix possible warning on checking all pages used in ftrace_process_locs()Zheng Yejian
commit 26efd79c4624294e553aeaa3439c646729bad084 upstream. As comments in ftrace_process_locs(), there may be NULL pointers in mcount_loc section: > Some architecture linkers will pad between > the different mcount_loc sections of different > object files to satisfy alignments. > Skip any NULL pointers. After commit 20e5227e9f55 ("ftrace: allow NULL pointers in mcount_loc"), NULL pointers will be accounted when allocating ftrace pages but skipped before adding into ftrace pages, this may result in some pages not being used. Then after commit 706c81f87f84 ("ftrace: Remove extra helper functions"), warning may occur at: WARN_ON(pg->next); To fix it, only warn for case that no pointers skipped but pages not used up, then free those unused pages after releasing ftrace_lock. Link: https://lore.kernel.org/linux-trace-kernel/20230712060452.3175675-1-zhengyejian1@huawei.com Cc: stable@vger.kernel.org Fixes: 706c81f87f84 ("ftrace: Remove extra helper functions") Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-23ring-buffer: Fix deadloop issue on reading trace_pipeZheng Yejian
commit 7e42907f3a7b4ce3a2d1757f6d78336984daf8f5 upstream. Soft lockup occurs when reading file 'trace_pipe': watchdog: BUG: soft lockup - CPU#6 stuck for 22s! [cat:4488] [...] RIP: 0010:ring_buffer_empty_cpu+0xed/0x170 RSP: 0018:ffff88810dd6fc48 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000246 RCX: ffffffff93d1aaeb RDX: ffff88810a280040 RSI: 0000000000000008 RDI: ffff88811164b218 RBP: ffff88811164b218 R08: 0000000000000000 R09: ffff88815156600f R10: ffffed102a2acc01 R11: 0000000000000001 R12: 0000000051651901 R13: 0000000000000000 R14: ffff888115e49500 R15: 0000000000000000 [...] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8d853c2000 CR3: 000000010dcd8000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __find_next_entry+0x1a8/0x4b0 ? peek_next_entry+0x250/0x250 ? down_write+0xa5/0x120 ? down_write_killable+0x130/0x130 trace_find_next_entry_inc+0x3b/0x1d0 tracing_read_pipe+0x423/0xae0 ? tracing_splice_read_pipe+0xcb0/0xcb0 vfs_read+0x16b/0x490 ksys_read+0x105/0x210 ? __ia32_sys_pwrite64+0x200/0x200 ? switch_fpu_return+0x108/0x220 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x61/0xc6 Through the vmcore, I found it's because in tracing_read_pipe(), ring_buffer_empty_cpu() found some buffer is not empty but then it cannot read anything due to "rb_num_of_entries() == 0" always true, Then it infinitely loop the procedure due to user buffer not been filled, see following code path: tracing_read_pipe() { ... ... waitagain: tracing_wait_pipe() // 1. find non-empty buffer here trace_find_next_entry_inc() // 2. loop here try to find an entry __find_next_entry() ring_buffer_empty_cpu(); // 3. find non-empty buffer peek_next_entry() // 4. but peek always return NULL ring_buffer_peek() rb_buffer_peek() rb_get_reader_page() // 5. because rb_num_of_entries() == 0 always true here // then return NULL // 6. user buffer not been filled so goto 'waitgain' // and eventually leads to an deadloop in kernel!!! } By some analyzing, I found that when resetting ringbuffer, the 'entries' of its pages are not all cleared (see rb_reset_cpu()). Then when reducing the ringbuffer, and if some reduced pages exist dirty 'entries' data, they will be added into 'cpu_buffer->overrun' (see rb_remove_pages()), which cause wrong 'overrun' count and eventually cause the deadloop issue. To fix it, we need to clear every pages in rb_reset_cpu(). Link: https://lore.kernel.org/linux-trace-kernel/20230708225144.3785600-1-zhengyejian1@huawei.com Cc: stable@vger.kernel.org Fixes: a5fb833172eca ("ring-buffer: Fix uninitialized read_stamp") Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-23tracing: Fix memory leak of iter->temp when reading trace_pipeZheng Yejian
commit d5a821896360cc8b93a15bd888fabc858c038dc0 upstream. kmemleak reports: unreferenced object 0xffff88814d14e200 (size 256): comm "cat", pid 336, jiffies 4294871818 (age 779.490s) hex dump (first 32 bytes): 04 00 01 03 00 00 00 00 08 00 00 00 00 00 00 00 ................ 0c d8 c8 9b ff ff ff ff 04 5a ca 9b ff ff ff ff .........Z...... backtrace: [<ffffffff9bdff18f>] __kmalloc+0x4f/0x140 [<ffffffff9bc9238b>] trace_find_next_entry+0xbb/0x1d0 [<ffffffff9bc9caef>] trace_print_lat_context+0xaf/0x4e0 [<ffffffff9bc94490>] print_trace_line+0x3e0/0x950 [<ffffffff9bc95499>] tracing_read_pipe+0x2d9/0x5a0 [<ffffffff9bf03a43>] vfs_read+0x143/0x520 [<ffffffff9bf04c2d>] ksys_read+0xbd/0x160 [<ffffffff9d0f0edf>] do_syscall_64+0x3f/0x90 [<ffffffff9d2000aa>] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 when reading file 'trace_pipe', 'iter->temp' is allocated or relocated in trace_find_next_entry() but not freed before 'trace_pipe' is closed. To fix it, free 'iter->temp' in tracing_release_pipe(). Link: https://lore.kernel.org/linux-trace-kernel/20230713141435.1133021-1-zhengyejian1@huawei.com Cc: stable@vger.kernel.org Fixes: ff895103a84ab ("tracing: Save off entry when peeking at next entry") Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-23tracing/histograms: Add histograms to hist_vars if they have referenced ↵Mohamed Khalfella
variables commit 6018b585e8c6fa7d85d4b38d9ce49a5b67be7078 upstream. Hist triggers can have referenced variables without having direct variables fields. This can be the case if referenced variables are added for trigger actions. In this case the newly added references will not have field variables. Not taking such referenced variables into consideration can result in a bug where it would be possible to remove hist trigger with variables being refenced. This will result in a bug that is easily reproducable like so $ cd /sys/kernel/tracing $ echo 'synthetic_sys_enter char[] comm; long id' >> synthetic_events $ echo 'hist:keys=common_pid.execname,id.syscall:vals=hitcount:comm=common_pid.execname' >> events/raw_syscalls/sys_enter/trigger $ echo 'hist:keys=common_pid.execname,id.syscall:onmatch(raw_syscalls.sys_enter).synthetic_sys_enter($comm, id)' >> events/raw_syscalls/sys_enter/trigger $ echo '!hist:keys=common_pid.execname,id.syscall:vals=hitcount:comm=common_pid.execname' >> events/raw_syscalls/sys_enter/trigger [ 100.263533] ================================================================== [ 100.264634] BUG: KASAN: slab-use-after-free in resolve_var_refs+0xc7/0x180 [ 100.265520] Read of size 8 at addr ffff88810375d0f0 by task bash/439 [ 100.266320] [ 100.266533] CPU: 2 PID: 439 Comm: bash Not tainted 6.5.0-rc1 #4 [ 100.267277] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-20220807_005459-localhost 04/01/2014 [ 100.268561] Call Trace: [ 100.268902] <TASK> [ 100.269189] dump_stack_lvl+0x4c/0x70 [ 100.269680] print_report+0xc5/0x600 [ 100.270165] ? resolve_var_refs+0xc7/0x180 [ 100.270697] ? kasan_complete_mode_report_info+0x80/0x1f0 [ 100.271389] ? resolve_var_refs+0xc7/0x180 [ 100.271913] kasan_report+0xbd/0x100 [ 100.272380] ? resolve_var_refs+0xc7/0x180 [ 100.272920] __asan_load8+0x71/0xa0 [ 100.273377] resolve_var_refs+0xc7/0x180 [ 100.273888] event_hist_trigger+0x749/0x860 [ 100.274505] ? kasan_save_stack+0x2a/0x50 [ 100.275024] ? kasan_set_track+0x29/0x40 [ 100.275536] ? __pfx_event_hist_trigger+0x10/0x10 [ 100.276138] ? ksys_write+0xd1/0x170 [ 100.276607] ? do_syscall_64+0x3c/0x90 [ 100.277099] ? entry_SYSCALL_64_after_hwframe+0x6e/0xd8 [ 100.277771] ? destroy_hist_data+0x446/0x470 [ 100.278324] ? event_hist_trigger_parse+0xa6c/0x3860 [ 100.278962] ? __pfx_event_hist_trigger_parse+0x10/0x10 [ 100.279627] ? __kasan_check_write+0x18/0x20 [ 100.280177] ? mutex_unlock+0x85/0xd0 [ 100.280660] ? __pfx_mutex_unlock+0x10/0x10 [ 100.281200] ? kfree+0x7b/0x120 [ 100.281619] ? ____kasan_slab_free+0x15d/0x1d0 [ 100.282197] ? event_trigger_write+0xac/0x100 [ 100.282764] ? __kasan_slab_free+0x16/0x20 [ 100.283293] ? __kmem_cache_free+0x153/0x2f0 [ 100.283844] ? sched_mm_cid_remote_clear+0xb1/0x250 [ 100.284550] ? __pfx_sched_mm_cid_remote_clear+0x10/0x10 [ 100.285221] ? event_trigger_write+0xbc/0x100 [ 100.285781] ? __kasan_check_read+0x15/0x20 [ 100.286321] ? __bitmap_weight+0x66/0xa0 [ 100.286833] ? _find_next_bit+0x46/0xe0 [ 100.287334] ? task_mm_cid_work+0x37f/0x450 [ 100.287872] event_triggers_call+0x84/0x150 [ 100.288408] trace_event_buffer_commit+0x339/0x430 [ 100.289073] ? ring_buffer_event_data+0x3f/0x60 [ 100.292189] trace_event_raw_event_sys_enter+0x8b/0xe0 [ 100.295434] syscall_trace_enter.constprop.0+0x18f/0x1b0 [ 100.298653] syscall_enter_from_user_mode+0x32/0x40 [ 100.301808] do_syscall_64+0x1a/0x90 [ 100.304748] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 [ 100.307775] RIP: 0033:0x7f686c75c1cb [ 100.310617] Code: 73 01 c3 48 8b 0d 65 3c 10 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 21 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 35 3c 10 00 f7 d8 64 89 01 48 [ 100.317847] RSP: 002b:00007ffc60137a38 EFLAGS: 00000246 ORIG_RAX: 0000000000000021 [ 100.321200] RAX: ffffffffffffffda RBX: 000055f566469ea0 RCX: 00007f686c75c1cb [ 100.324631] RDX: 0000000000000001 RSI: 0000000000000001 RDI: 000000000000000a [ 100.328104] RBP: 00007ffc60137ac0 R08: 00007f686c818460 R09: 000000000000000a [ 100.331509] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000009 [ 100.334992] R13: 0000000000000007 R14: 000000000000000a R15: 0000000000000007 [ 100.338381] </TASK> We hit the bug because when second hist trigger has was created has_hist_vars() returned false because hist trigger did not have variables. As a result of that save_hist_vars() was not called to add the trigger to trace_array->hist_vars. Later on when we attempted to remove the first histogram find_any_var_ref() failed to detect it is being used because it did not find the second trigger in hist_vars list. With this change we wait until trigger actions are created so we can take into consideration if hist trigger has variable references. Also, now we check the return value of save_hist_vars() and fail trigger creation if save_hist_vars() fails. Link: https://lore.kernel.org/linux-trace-kernel/20230712223021.636335-1-mkhalfella@purestorage.com Cc: stable@vger.kernel.org Fixes: 067fe038e70f6 ("tracing: Add variable reference handling to hist triggers") Signed-off-by: Mohamed Khalfella <mkhalfella@purestorage.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-23tracing/user_events: Fix incorrect return value for writing operation when ↵sunliming
events are disabled commit f6d026eea390d59787a6cdc2ef5c983d02e029d0 upstream. The writing operation return the count of writes regardless of whether events are enabled or disabled. Switch it to return -EBADF to indicates that the event is disabled. Link: https://lkml.kernel.org/r/20230626111344.19136-2-sunliming@kylinos.cn Cc: stable@vger.kernel.org 7f5a08c79df35 ("user_events: Add minimal support for trace_event into ftrace") Acked-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: sunliming <sunliming@kylinos.cn> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-23fprobe: add unlock to match a succeeded ftrace_test_recursion_trylockZe Gao
[ Upstream commit 5f0c584daf7464f04114c65dd07269ee2bfedc13 ] Unlock ftrace recursion lock when fprobe_kprobe_handler() is failed because of some running kprobe. Link: https://lore.kernel.org/all/20230703092336.268371-1-zegao@tencent.com/ Fixes: 3cc4e2c5fbae ("fprobe: make fprobe_kprobe_handler recursion free") Reported-by: Yafang <laoar.shao@gmail.com> Closes: https://lore.kernel.org/linux-trace-kernel/CALOAHbC6UpfFOOibdDiC7xFc5YFUgZnk3MZ=3Ny6we=AcrNbew@mail.gmail.com/ Signed-off-by: Ze Gao <zegao@tencent.com> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Acked-by: Yafang Shao <laoar.shao@gmail.com> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-23kernel/trace: Fix cleanup logic of enable_trace_eprobeTzvetomir Stoyanov (VMware)
[ Upstream commit cf0a624dc706c306294c14e6b3e7694702f25191 ] The enable_trace_eprobe() function enables all event probes, attached to given trace probe. If an error occurs in enabling one of the event probes, all others should be roll backed. There is a bug in that roll back logic - instead of all event probes, only the failed one is disabled. Link: https://lore.kernel.org/all/20230703042853.1427493-1-tz.stoyanov@gmail.com/ Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Fixes: 7491e2c44278 ("tracing: Add a probe that attaches to trace events") Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-06-20Merge tag 'trace-v6.4-rc6' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix MAINTAINERS file to point to proper mailing list for rtla and rv The mailing list pointed to linux-trace-devel instead of linux-trace-kernel. The former is for the tracing libraries and the latter is for anything in the Linux kernel tree. The wrong mailing list was used because linux-trace-kernel did not exist when rtla and rv were created. - User events: - Fix matching of dynamic events to their user events When user writes to dynamic_events file, a lookup of the registered dynamic events is made, but there were some cases that a match could be incorrectly made. - Add auto cleanup of user events Have the user events automatically get removed when the last reference (file descriptor) is closed. This was asked for to prevent leaks of user events hanging around needing admins to clean them up. - Add persistent logic (but not let user space use it yet) In some cases, having a persistent user event (one that does not get cleaned up automatically) is useful. But there's still debates about how to expose this to user space. The infrastructure is added, but the API is not. - Update the selftests Update the user event selftests to reflect the above changes" * tag 'trace-v6.4-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing/user_events: Document auto-cleanup and remove dyn_event refs selftests/user_events: Adapt dyn_test to non-persist events selftests/user_events: Ensure auto cleanup works as expected tracing/user_events: Add auto cleanup and future persist flag tracing/user_events: Track refcount consistently via put/get tracing/user_events: Store register flags on events tracing/user_events: Remove user_ns walk for groups selftests/user_events: Add perf self-test for empty arguments events selftests/user_events: Clear the events after perf self-test selftests/user_events: Add ftrace self-test for empty arguments events tracing/user_events: Fix the incorrect trace record for empty arguments events tracing: Modify print_fields() for fields output order tracing/user_events: Handle matching arguments that is null from dyn_events tracing/user_events: Prevent same name but different args event tracing/rv/rtla: Update MAINTAINERS file to point to proper mailing list
2023-06-14tracing/user_events: Add auto cleanup and future persist flagBeau Belgrave
Currently user events need to be manually deleted via the delete IOCTL call or via the dynamic_events file. Most operators and processes wish to have these events auto cleanup when they are no longer used by anything to prevent them piling without manual maintenance. However, some operators may not want this, such as pre-registering events via the dynamic_events tracefs file. Update user_event_put() to attempt an auto delete of the event if it's the last reference. The auto delete must run in a work queue to ensure proper behavior of class->reg() invocations that don't expect the call to go away from underneath them during the unregister. Add work_struct to user_event struct to ensure we can do this reliably. Add a persist flag, that is not yet exposed, to ensure we can toggle between auto-cleanup and leaving the events existing in the future. When a non-zero flag is seen during register, return -EINVAL to ensure ABI is clear for the user processes while we work out the best approach for persistent events. Link: https://lkml.kernel.org/r/20230614163336.5797-4-beaub@linux.microsoft.com Link: https://lore.kernel.org/linux-trace-kernel/20230518093600.3f119d68@rorschach.local.home/ Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-14tracing/user_events: Track refcount consistently via put/getBeau Belgrave
Various parts of the code today track user_event's refcnt field directly via a refcount_add/dec. This makes it hard to modify the behavior of the last reference decrement in all code paths consistently. For example, in the future we will auto-delete events upon the last reference going away. This last reference could happen in many places, but we want it to be consistently handled. Add user_event_get() and user_event_put() for the add/dec. Update all places where direct refcounts are being used to utilize these new functions. In each location pass if event_mutex is locked or not. This allows us to drop events automatically in future patches clearly. Ensure when caller states the lock is held, it really is (or is not) held. Link: https://lkml.kernel.org/r/20230614163336.5797-3-beaub@linux.microsoft.com Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-14tracing/user_events: Store register flags on eventsBeau Belgrave
Currently we don't have any available flags for user processes to use to indicate options for user_events. We will soon have a flag to indicate the event should or should not auto-delete once it's not being used by anyone. Add a reg_flags field to user_events and parameters to existing functions to allow for this in future patches. Link: https://lkml.kernel.org/r/20230614163336.5797-2-beaub@linux.microsoft.com Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-14tracing/user_events: Remove user_ns walk for groupsBeau Belgrave
During discussions it was suggested that user_ns is not a good place to try to attach a tracing namespace. The current code has stubs to enable that work that are very likely to change and incur a performance cost. Remove the user_ns walk when creating a group and determining the system name to use, since it's unlikely user_ns will be used in the future. Link: https://lore.kernel.org/all/20230601-urenkel-holzofen-cd9403b9cadd@brauner/ Link: https://lore.kernel.org/linux-trace-kernel/20230601224928.301-1-beaub@linux.microsoft.com Suggested-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-14tracing/user_events: Fix the incorrect trace record for empty arguments eventssunliming
The user_events support events that has empty arguments. But the trace event is discarded and not really committed when the arguments is empty. Fix this by not attempting to copy in zero-length data. Link: https://lkml.kernel.org/r/20230606062027.1008398-2-sunliming@kylinos.cn Acked-by: Beau Belgrave <beaub@linux.microsoft.com> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: sunliming <sunliming@kylinos.cn> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-14tracing: Modify print_fields() for fields output ordersunliming
Now the print_fields() print trace event fields in reverse order. Modify it to the positive sequence. Example outputs for a user event: test0 u32 count1; u32 count2 Output before: example-2547 [000] ..... 325.666387: test0: count2=0x2 (2) count1=0x1 (1) Output after: example-2742 [002] ..... 429.769370: test0: count1=0x1 (1) count2=0x2 (2) Link: https://lore.kernel.org/linux-trace-kernel/20230525085232.5096-1-sunliming@kylinos.cn Fixes: 80a76994b2d88 ("tracing: Add "fields" option to show raw trace event fields") Signed-off-by: sunliming <sunliming@kylinos.cn> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-14tracing/user_events: Handle matching arguments that is null from dyn_eventssunliming
When A registering user event from dyn_events has no argments, it will pass the matching check, regardless of whether there is a user event with the same name and arguments. Add the matching check when the arguments of registering user event is null. Link: https://lore.kernel.org/linux-trace-kernel/20230529065110.303440-1-sunliming@kylinos.cn Signed-off-by: sunliming <sunliming@kylinos.cn> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-14tracing/user_events: Prevent same name but different args eventsunliming
User processes register name_args for events. If the same name but different args event are registered. The trace outputs of second event are printed as the first event. This is incorrect. Return EADDRINUSE back to the user process if the same name but different args event has being registered. Link: https://lore.kernel.org/linux-trace-kernel/20230529032100.286534-1-sunliming@kylinos.cn Signed-off-by: sunliming <sunliming@kylinos.cn> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Acked-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-08Merge tag 'net-6.4-rc6' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net Pull networking fixes from Paolo Abeni: "Including fixes from can, wifi, netfilter, bluetooth and ebpf. Current release - regressions: - bpf: sockmap: avoid potential NULL dereference in sk_psock_verdict_data_ready() - wifi: iwlwifi: fix -Warray-bounds bug in iwl_mvm_wait_d3_notif() - phylink: actually fix ksettings_set() ethtool call - eth: dwmac-qcom-ethqos: fix a regression on EMAC < 3 Current release - new code bugs: - wifi: mt76: fix possible NULL pointer dereference in mt7996_mac_write_txwi() Previous releases - regressions: - netfilter: fix NULL pointer dereference in nf_confirm_cthelper - wifi: rtw88/rtw89: correct PS calculation for SUPPORTS_DYNAMIC_PS - openvswitch: fix upcall counter access before allocation - bluetooth: - fix use-after-free in hci_remove_ltk/hci_remove_irk - fix l2cap_disconnect_req deadlock - nic: bnxt_en: prevent kernel panic when receiving unexpected PHC_UPDATE event Previous releases - always broken: - core: annotate rfs lockless accesses - sched: fq_pie: ensure reasonable TCA_FQ_PIE_QUANTUM values - netfilter: add null check for nla_nest_start_noflag() in nft_dump_basechain_hook() - bpf: fix UAF in task local storage - ipv4: ping_group_range: allow GID from 2147483648 to 4294967294 - ipv6: rpl: fix route of death. - tcp: gso: really support BIG TCP - mptcp: fixes for user-space PM address advertisement - smc: avoid to access invalid RMBs' MRs in SMCRv1 ADD LINK CONT - can: avoid possible use-after-free when j1939_can_rx_register fails - batman-adv: fix UaF while rescheduling delayed work - eth: qede: fix scheduling while atomic - eth: ice: make writes to /dev/gnssX synchronous" * tag 'net-6.4-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (83 commits) bnxt_en: Implement .set_port / .unset_port UDP tunnel callbacks bnxt_en: Prevent kernel panic when receiving unexpected PHC_UPDATE event bnxt_en: Skip firmware fatal error recovery if chip is not accessible bnxt_en: Query default VLAN before VNIC setup on a VF bnxt_en: Don't issue AP reset during ethtool's reset operation bnxt_en: Fix bnxt_hwrm_update_rss_hash_cfg() net: bcmgenet: Fix EEE implementation eth: ixgbe: fix the wake condition eth: bnxt: fix the wake condition lib: cpu_rmap: Fix potential use-after-free in irq_cpu_rmap_release() bpf: Add extra path pointer check to d_path helper net: sched: fix possible refcount leak in tc_chain_tmplt_add() net: sched: act_police: fix sparse errors in tcf_police_dump() net: openvswitch: fix upcall counter access before allocation net: sched: move rtm_tca_policy declaration to include file ice: make writes to /dev/gnssX synchronous net: sched: add rcu annotations around qdisc->qdisc_sleeping rfs: annotate lockless accesses to RFS sock flow table rfs: annotate lockless accesses to sk->sk_rxhash virtio_net: use control_buf for coalesce params ...
2023-06-07Merge tag 'for-netdev' of ↵Jakub Kicinski
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf Daniel Borkmann says: ==================== pull-request: bpf 2023-06-07 We've added 7 non-merge commits during the last 7 day(s) which contain a total of 12 files changed, 112 insertions(+), 7 deletions(-). The main changes are: 1) Fix a use-after-free in BPF's task local storage, from KP Singh. 2) Make struct path handling more robust in bpf_d_path, from Jiri Olsa. 3) Fix a syzbot NULL-pointer dereference in sockmap, from Eric Dumazet. 4) UAPI fix for BPF_NETFILTER before final kernel ships, from Florian Westphal. 5) Fix map-in-map array_map_gen_lookup code generation where elem_size was not being set for inner maps, from Rhys Rustad-Elliott. 6) Fix sockopt_sk selftest's NETLINK_LIST_MEMBERSHIPS assertion, from Yonghong Song. * tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: bpf: Add extra path pointer check to d_path helper selftests/bpf: Fix sockopt_sk selftest bpf: netfilter: Add BPF_NETFILTER bpf_attach_type selftests/bpf: Add access_inner_map selftest bpf: Fix elem_size not being set for inner maps bpf: Fix UAF in task local storage bpf, sockmap: Avoid potential NULL dereference in sk_psock_verdict_data_ready() ==================== Link: https://lore.kernel.org/r/20230607220514.29698-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-06-07bpf: Add extra path pointer check to d_path helperJiri Olsa
Anastasios reported crash on stable 5.15 kernel with following BPF attached to lsm hook: SEC("lsm.s/bprm_creds_for_exec") int BPF_PROG(bprm_creds_for_exec, struct linux_binprm *bprm) { struct path *path = &bprm->executable->f_path; char p[128] = { 0 }; bpf_d_path(path, p, 128); return 0; } But bprm->executable can be NULL, so bpf_d_path call will crash: BUG: kernel NULL pointer dereference, address: 0000000000000018 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC NOPTI ... RIP: 0010:d_path+0x22/0x280 ... Call Trace: <TASK> bpf_d_path+0x21/0x60 bpf_prog_db9cf176e84498d9_bprm_creds_for_exec+0x94/0x99 bpf_trampoline_6442506293_0+0x55/0x1000 bpf_lsm_bprm_creds_for_exec+0x5/0x10 security_bprm_creds_for_exec+0x29/0x40 bprm_execve+0x1c1/0x900 do_execveat_common.isra.0+0x1af/0x260 __x64_sys_execve+0x32/0x40 It's problem for all stable trees with bpf_d_path helper, which was added in 5.9. This issue is fixed in current bpf code, where we identify and mark trusted pointers, so the above code would fail even to load. For the sake of the stable trees and to workaround potentially broken verifier in the future, adding the code that reads the path object from the passed pointer and verifies it's valid in kernel space. Fixes: 6e22ab9da793 ("bpf: Add d_path helper") Reported-by: Anastasios Papagiannis <tasos.papagiannnis@gmail.com> Suggested-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Stanislav Fomichev <sdf@google.com> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20230606181714.532998-1-jolsa@kernel.org
2023-06-03Merge tag 'probes-fixes-6.4-rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull probes fixes from Masami Hiramatsu: - Return NULL if the trace_probe list on trace_probe_event is empty - selftests/ftrace: Choose testing symbol name for filtering feature from sample data instead of fixed symbol * tag 'probes-fixes-6.4-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: selftests/ftrace: Choose target function for filter test from samples tracing/probe: trace_probe_primary_from_call(): checked list_first_entry
2023-05-31tracing/probe: trace_probe_primary_from_call(): checked list_first_entryPietro Borrello
All callers of trace_probe_primary_from_call() check the return value to be non NULL. However, the function returns list_first_entry(&tpe->probes, ...) which can never be NULL. Additionally, it does not check for the list being possibly empty, possibly causing a type confusion on empty lists. Use list_first_entry_or_null() which solves both problems. Link: https://lore.kernel.org/linux-trace-kernel/20230128-list-entry-null-check-v1-1-8bde6a3da2ef@diag.uniroma1.it/ Fixes: 60d53e2c3b75 ("tracing/probe: Split trace_event related data from trace_probe") Signed-off-by: Pietro Borrello <borrello@diag.uniroma1.it> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Acked-by: Mukesh Ojha <quic_mojha@quicinc.com> Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2023-05-28tracing: Have function_graph selftest call cond_resched()Steven Rostedt (Google)
When all kernel debugging is enabled (lockdep, KSAN, etc), the function graph enabling and disabling can take several seconds to complete. The function_graph selftest enables and disables function graph tracing several times. With full debugging enabled, the soft lockup watchdog was triggering because the selftest was running without ever scheduling. Add cond_resched() throughout the test to make sure it does not trigger the soft lockup detector. Link: https://lkml.kernel.org/r/20230528051742.1325503-6-rostedt@goodmis.org Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-05-28tracing: Only make selftest conditionals affect the global_traceSteven Rostedt (Google)
The tracing_selftest_running and tracing_selftest_disabled variables were to keep trace_printk() and other writes from affecting the tracing selftests, as the tracing selftests would examine the ring buffer to see if it contained what it expected or not. trace_printk() and friends could add to the ring buffer and cause the selftests to fail (and then disable the tracer that was being tested). To keep that from happening, these variables were added and would keep trace_printk() and friends from writing to the ring buffer while the tests were going on. But this was only the top level ring buffer (owned by the global_trace instance). There is no reason to prevent writing into ring buffers of other instances via the trace_array_printk() and friends. For the functions that could be used by other instances, check if the global_trace is the tracer instance that is being written to before deciding to not allow the write. Link: https://lkml.kernel.org/r/20230528051742.1325503-5-rostedt@goodmis.org Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-05-28tracing: Make tracing_selftest_running/delete nops when not usedSteven Rostedt (Google)
There's no reason to test the condition variables tracing_selftest_running or tracing_selftest_delete when tracing selftests are not enabled. Make them define 0s when not the selftests are not configured in. Link: https://lkml.kernel.org/r/20230528051742.1325503-4-rostedt@goodmis.org Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-05-28tracing: Have tracer selftests call cond_resched() before runningSteven Rostedt (Google)
As there are more and more internal selftests being added to the Linux kernel (KSAN, lockdep, etc) the selftests are taking longer to run when these are enabled. Add a cond_resched() to the calling of do_run_tracer_selftest() to force a schedule if NEED_RESCHED is set, otherwise the soft lockup watchdog may trigger on boot up. Link: https://lkml.kernel.org/r/20230528051742.1325503-3-rostedt@goodmis.org Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-05-28tracing: Move setting of tracing_selftest_running out of register_tracer()Steven Rostedt (Google)
The variables tracing_selftest_running and tracing_selftest_disabled are only used for when CONFIG_FTRACE_STARTUP_TEST is enabled. Make them only visible within the selftest code. The setting of those variables are in the register_tracer() call, and set in a location where they do not need to be. Create a wrapper around run_tracer_selftest() called do_run_tracer_selftest() which sets those variables, and have register_tracer() call that instead. Having those variables only set within the CONFIG_FTRACE_STARTUP_TEST scope gets rid of them (and also the ability to remove testing against them) when the startup tests are not enabled (most cases). Link: https://lkml.kernel.org/r/20230528051742.1325503-2-rostedt@goodmis.org Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-05-23tracing: Rename stacktrace field to common_stacktraceSteven Rostedt (Google)
The histogram and synthetic events can use a pseudo event called "stacktrace" that will create a stacktrace at the time of the event and use it just like it was a normal field. We have other pseudo events such as "common_cpu" and "common_timestamp". To stay consistent with that, convert "stacktrace" to "common_stacktrace". As this was used in older kernels, to keep backward compatibility, this will act just like "common_cpu" did with "cpu". That is, "cpu" will be the same as "common_cpu" unless the event has a "cpu" field. In which case, the event's field is used. The same is true with "stacktrace". Also update the documentation to reflect this change. Link: https://lore.kernel.org/linux-trace-kernel/20230523230913.6860e28d@rorschach.local.home Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-05-23tracing/histograms: Allow variables to have some modifiersSteven Rostedt (Google)
Modifiers are used to change the behavior of keys. For instance, they can grouped into buckets, converted to syscall names (from the syscall identifier), show task->comm of the current pid, be an array of longs that represent a stacktrace, and more. It was found that nothing stopped a value from taking a modifier. As values are simple counters. If this happened, it would call code that was not expecting a modifier and crash the kernel. This was fixed by having the ___create_val_field() function test if a modifier was present and fail if one was. This fixed the crash. Now there's a problem with variables. Variables are used to pass fields from one event to another. Variables are allowed to have some modifiers, as the processing may need to happen at the time of the event (like stacktraces and comm names of the current pid). The issue is that it too uses __create_val_field(). Now that fails on modifiers, variables can no longer use them (this is a regression). As not all modifiers are for variables, have them use a separate check. Link: https://lore.kernel.org/linux-trace-kernel/20230523221108.064a5d82@rorschach.local.home Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Fixes: e0213434fe3e4 ("tracing: Do not let histogram values have some modifiers") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-05-23tracing/user_events: Document user_event_mm one-shot list usageBeau Belgrave
During 6.4 development it became clear that the one-shot list used by the user_event_mm's next field was confusing to others. It is not clear how this list is protected or what the next field usage is for unless you are familiar with the code. Add comments into the user_event_mm struct indicating lock requirement and usage. Also document how and why this approach was used via comments in both user_event_enabler_update() and user_event_mm_get_all() and the rules to properly use it. Link: https://lkml.kernel.org/r/20230519230741.669-5-beaub@linux.microsoft.com Link: https://lore.kernel.org/linux-trace-kernel/CAHk-=wicngggxVpbnrYHjRTwGE0WYscPRM+L2HO2BF8ia1EXgQ@mail.gmail.com/ Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-05-23tracing/user_events: Rename link fields for clarityBeau Belgrave
Currently most list_head fields of various structs within user_events are simply named link. This causes folks to keep additional context in their head when working with the code, which can be confusing. Instead of using link, describe what the actual link is, for example: list_del_rcu(&mm->link); Changes into: list_del_rcu(&mm->mms_link); The reader now is given a hint the link is to the mms global list instead of having to remember or spot check within the code. Link: https://lkml.kernel.org/r/20230519230741.669-4-beaub@linux.microsoft.com Link: https://lore.kernel.org/linux-trace-kernel/CAHk-=wicngggxVpbnrYHjRTwGE0WYscPRM+L2HO2BF8ia1EXgQ@mail.gmail.com/ Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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