summaryrefslogtreecommitdiff
path: root/kernel
AgeCommit message (Collapse)Author
2023-12-13perf: Fix perf_event_validate_size()Peter Zijlstra
[ Upstream commit 382c27f4ed28f803b1f1473ac2d8db0afc795a1b ] Budimir noted that perf_event_validate_size() only checks the size of the newly added event, even though the sizes of all existing events can also change due to not all events having the same read_format. When we attach the new event, perf_group_attach(), we do re-compute the size for all events. Fixes: a723968c0ed3 ("perf: Fix u16 overflows") Reported-by: Budimir Markovic <markovicbudimir@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-12-13perf/core: Add a new read format to get a number of lost samplesNamhyung Kim
[ Upstream commit 119a784c81270eb88e573174ed2209225d646656 ] Sometimes we want to know an accurate number of samples even if it's lost. Currenlty PERF_RECORD_LOST is generated for a ring-buffer which might be shared with other events. So it's hard to know per-event lost count. Add event->lost_samples field and PERF_FORMAT_LOST to retrieve it from userspace. Original-patch-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220616180623.1358843-1-namhyung@kernel.org Stable-dep-of: 382c27f4ed28 ("perf: Fix perf_event_validate_size()") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-12-13tracing: Stop current tracer when resizing bufferSteven Rostedt (Google)
[ Upstream commit d78ab792705c7be1b91243b2544d1a79406a2ad7 ] When the ring buffer is being resized, it can cause side effects to the running tracer. For instance, there's a race with irqsoff tracer that swaps individual per cpu buffers between the main buffer and the snapshot buffer. The resize operation modifies the main buffer and then the snapshot buffer. If a swap happens in between those two operations it will break the tracer. Simply stop the running tracer before resizing the buffers and enable it again when finished. Link: https://lkml.kernel.org/r/20231205220010.748996423@goodmis.org Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Fixes: 3928a8a2d9808 ("ftrace: make work with new ring buffer") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-12-13tracing: Set actual size after ring buffer resizeZheng Yejian
[ Upstream commit 6d98a0f2ac3c021d21be66fa34e992137cd25bcb ] Currently we can resize trace ringbuffer by writing a value into file 'buffer_size_kb', then by reading the file, we get the value that is usually what we wrote. However, this value may be not actual size of trace ring buffer because of the round up when doing resize in kernel, and the actual size would be more useful. Link: https://lore.kernel.org/linux-trace-kernel/20230705002705.576633-1-zhengyejian1@huawei.com Cc: <mhiramat@kernel.org> Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Stable-dep-of: d78ab792705c ("tracing: Stop current tracer when resizing buffer") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-12-13ring-buffer: Force absolute timestamp on discard of eventSteven Rostedt (Google)
[ Upstream commit b2dd797543cfa6580eac8408dd67fa02164d9e56 ] There's a race where if an event is discarded from the ring buffer and an interrupt were to happen at that time and insert an event, the time stamp is still used from the discarded event as an offset. This can screw up the timings. If the event is going to be discarded, set the "before_stamp" to zero. When a new event comes in, it compares the "before_stamp" with the "write_stamp" and if they are not equal, it will insert an absolute timestamp. This will prevent the timings from getting out of sync due to the discarded event. Link: https://lore.kernel.org/linux-trace-kernel/20231206100244.5130f9b3@gandalf.local.home Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Fixes: 6f6be606e763f ("ring-buffer: Force before_stamp and write_stamp to be different on discard") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-12-13tracing: Fix a possible race when disabling buffered eventsPetr Pavlu
commit c0591b1cccf708a47bc465c62436d669a4213323 upstream. Function trace_buffered_event_disable() is responsible for freeing pages backing buffered events and this process can run concurrently with trace_event_buffer_lock_reserve(). The following race is currently possible: * Function trace_buffered_event_disable() is called on CPU 0. It increments trace_buffered_event_cnt on each CPU and waits via synchronize_rcu() for each user of trace_buffered_event to complete. * After synchronize_rcu() is finished, function trace_buffered_event_disable() has the exclusive access to trace_buffered_event. All counters trace_buffered_event_cnt are at 1 and all pointers trace_buffered_event are still valid. * At this point, on a different CPU 1, the execution reaches trace_event_buffer_lock_reserve(). The function calls preempt_disable_notrace() and only now enters an RCU read-side critical section. The function proceeds and reads a still valid pointer from trace_buffered_event[CPU1] into the local variable "entry". However, it doesn't yet read trace_buffered_event_cnt[CPU1] which happens later. * Function trace_buffered_event_disable() continues. It frees trace_buffered_event[CPU1] and decrements trace_buffered_event_cnt[CPU1] back to 0. * Function trace_event_buffer_lock_reserve() continues. It reads and increments trace_buffered_event_cnt[CPU1] from 0 to 1. This makes it believe that it can use the "entry" that it already obtained but the pointer is now invalid and any access results in a use-after-free. Fix the problem by making a second synchronize_rcu() call after all trace_buffered_event values are set to NULL. This waits on all potential users in trace_event_buffer_lock_reserve() that still read a previous pointer from trace_buffered_event. Link: https://lore.kernel.org/all/20231127151248.7232-2-petr.pavlu@suse.com/ Link: https://lkml.kernel.org/r/20231205161736.19663-4-petr.pavlu@suse.com Cc: stable@vger.kernel.org Fixes: 0fc1b09ff1ff ("tracing: Use temp buffer when filtering events") Signed-off-by: Petr Pavlu <petr.pavlu@suse.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-13tracing: Fix incomplete locking when disabling buffered eventsPetr Pavlu
commit 7fed14f7ac9cf5e38c693836fe4a874720141845 upstream. The following warning appears when using buffered events: [ 203.556451] WARNING: CPU: 53 PID: 10220 at kernel/trace/ring_buffer.c:3912 ring_buffer_discard_commit+0x2eb/0x420 [...] [ 203.670690] CPU: 53 PID: 10220 Comm: stress-ng-sysin Tainted: G E 6.7.0-rc2-default #4 56e6d0fcf5581e6e51eaaecbdaec2a2338c80f3a [ 203.670704] Hardware name: Intel Corp. GROVEPORT/GROVEPORT, BIOS GVPRCRB1.86B.0016.D04.1705030402 05/03/2017 [ 203.670709] RIP: 0010:ring_buffer_discard_commit+0x2eb/0x420 [ 203.735721] Code: 4c 8b 4a 50 48 8b 42 48 49 39 c1 0f 84 b3 00 00 00 49 83 e8 01 75 b1 48 8b 42 10 f0 ff 40 08 0f 0b e9 fc fe ff ff f0 ff 47 08 <0f> 0b e9 77 fd ff ff 48 8b 42 10 f0 ff 40 08 0f 0b e9 f5 fe ff ff [ 203.735734] RSP: 0018:ffffb4ae4f7b7d80 EFLAGS: 00010202 [ 203.735745] RAX: 0000000000000000 RBX: ffffb4ae4f7b7de0 RCX: ffff8ac10662c000 [ 203.735754] RDX: ffff8ac0c750be00 RSI: ffff8ac10662c000 RDI: ffff8ac0c004d400 [ 203.781832] RBP: ffff8ac0c039cea0 R08: 0000000000000000 R09: 0000000000000000 [ 203.781839] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 203.781842] R13: ffff8ac10662c000 R14: ffff8ac0c004d400 R15: ffff8ac10662c008 [ 203.781846] FS: 00007f4cd8a67740(0000) GS:ffff8ad798880000(0000) knlGS:0000000000000000 [ 203.781851] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 203.781855] CR2: 0000559766a74028 CR3: 00000001804c4000 CR4: 00000000001506f0 [ 203.781862] Call Trace: [ 203.781870] <TASK> [ 203.851949] trace_event_buffer_commit+0x1ea/0x250 [ 203.851967] trace_event_raw_event_sys_enter+0x83/0xe0 [ 203.851983] syscall_trace_enter.isra.0+0x182/0x1a0 [ 203.851990] do_syscall_64+0x3a/0xe0 [ 203.852075] entry_SYSCALL_64_after_hwframe+0x6e/0x76 [ 203.852090] RIP: 0033:0x7f4cd870fa77 [ 203.982920] Code: 00 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 90 b8 89 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e9 43 0e 00 f7 d8 64 89 01 48 [ 203.982932] RSP: 002b:00007fff99717dd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000089 [ 203.982942] RAX: ffffffffffffffda RBX: 0000558ea1d7b6f0 RCX: 00007f4cd870fa77 [ 203.982948] RDX: 0000000000000000 RSI: 00007fff99717de0 RDI: 0000558ea1d7b6f0 [ 203.982957] RBP: 00007fff99717de0 R08: 00007fff997180e0 R09: 00007fff997180e0 [ 203.982962] R10: 00007fff997180e0 R11: 0000000000000246 R12: 00007fff99717f40 [ 204.049239] R13: 00007fff99718590 R14: 0000558e9f2127a8 R15: 00007fff997180b0 [ 204.049256] </TASK> For instance, it can be triggered by running these two commands in parallel: $ while true; do echo hist:key=id.syscall:val=hitcount > \ /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger; done $ stress-ng --sysinfo $(nproc) The warning indicates that the current ring_buffer_per_cpu is not in the committing state. It happens because the active ring_buffer_event doesn't actually come from the ring_buffer_per_cpu but is allocated from trace_buffered_event. The bug is in function trace_buffered_event_disable() where the following normally happens: * The code invokes disable_trace_buffered_event() via smp_call_function_many() and follows it by synchronize_rcu(). This increments the per-CPU variable trace_buffered_event_cnt on each target CPU and grants trace_buffered_event_disable() the exclusive access to the per-CPU variable trace_buffered_event. * Maintenance is performed on trace_buffered_event, all per-CPU event buffers get freed. * The code invokes enable_trace_buffered_event() via smp_call_function_many(). This decrements trace_buffered_event_cnt and releases the access to trace_buffered_event. A problem is that smp_call_function_many() runs a given function on all target CPUs except on the current one. The following can then occur: * Task X executing trace_buffered_event_disable() runs on CPU 0. * The control reaches synchronize_rcu() and the task gets rescheduled on another CPU 1. * The RCU synchronization finishes. At this point, trace_buffered_event_disable() has the exclusive access to all trace_buffered_event variables except trace_buffered_event[CPU0] because trace_buffered_event_cnt[CPU0] is never incremented and if the buffer is currently unused, remains set to 0. * A different task Y is scheduled on CPU 0 and hits a trace event. The code in trace_event_buffer_lock_reserve() sees that trace_buffered_event_cnt[CPU0] is set to 0 and decides the use the buffer provided by trace_buffered_event[CPU0]. * Task X continues its execution in trace_buffered_event_disable(). The code incorrectly frees the event buffer pointed by trace_buffered_event[CPU0] and resets the variable to NULL. * Task Y writes event data to the now freed buffer and later detects the created inconsistency. The issue is observable since commit dea499781a11 ("tracing: Fix warning in trace_buffered_event_disable()") which moved the call of trace_buffered_event_disable() in __ftrace_event_enable_disable() earlier, prior to invoking call->class->reg(.. TRACE_REG_UNREGISTER ..). The underlying problem in trace_buffered_event_disable() is however present since the original implementation in commit 0fc1b09ff1ff ("tracing: Use temp buffer when filtering events"). Fix the problem by replacing the two smp_call_function_many() calls with on_each_cpu_mask() which invokes a given callback on all CPUs. Link: https://lore.kernel.org/all/20231127151248.7232-2-petr.pavlu@suse.com/ Link: https://lkml.kernel.org/r/20231205161736.19663-2-petr.pavlu@suse.com Cc: stable@vger.kernel.org Fixes: 0fc1b09ff1ff ("tracing: Use temp buffer when filtering events") Fixes: dea499781a11 ("tracing: Fix warning in trace_buffered_event_disable()") Signed-off-by: Petr Pavlu <petr.pavlu@suse.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-13tracing: Disable snapshot buffer when stopping instance tracersSteven Rostedt (Google)
commit b538bf7d0ec11ca49f536dfda742a5f6db90a798 upstream. It use to be that only the top level instance had a snapshot buffer (for latency tracers like wakeup and irqsoff). When stopping a tracer in an instance would not disable the snapshot buffer. This could have some unintended consequences if the irqsoff tracer is enabled. Consolidate the tracing_start/stop() with tracing_start/stop_tr() so that all instances behave the same. The tracing_start/stop() functions will just call their respective tracing_start/stop_tr() with the global_array passed in. Link: https://lkml.kernel.org/r/20231205220011.041220035@goodmis.org Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Fixes: 6d9b3fa5e7f6 ("tracing: Move tracing_max_latency into trace_array") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-13tracing: Always update snapshot buffer sizeSteven Rostedt (Google)
commit 7be76461f302ec05cbd62b90b2a05c64299ca01f upstream. It use to be that only the top level instance had a snapshot buffer (for latency tracers like wakeup and irqsoff). The update of the ring buffer size would check if the instance was the top level and if so, it would also update the snapshot buffer as it needs to be the same as the main buffer. Now that lower level instances also has a snapshot buffer, they too need to update their snapshot buffer sizes when the main buffer is changed, otherwise the following can be triggered: # cd /sys/kernel/tracing # echo 1500 > buffer_size_kb # mkdir instances/foo # echo irqsoff > instances/foo/current_tracer # echo 1000 > instances/foo/buffer_size_kb Produces: WARNING: CPU: 2 PID: 856 at kernel/trace/trace.c:1938 update_max_tr_single.part.0+0x27d/0x320 Which is: ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->array_buffer.buffer, cpu); if (ret == -EBUSY) { [..] } WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY); <== here That's because ring_buffer_swap_cpu() has: int ret = -EINVAL; [..] /* At least make sure the two buffers are somewhat the same */ if (cpu_buffer_a->nr_pages != cpu_buffer_b->nr_pages) goto out; [..] out: return ret; } Instead, update all instances' snapshot buffer sizes when their main buffer size is updated. Link: https://lkml.kernel.org/r/20231205220010.454662151@goodmis.org Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Fixes: 6d9b3fa5e7f6 ("tracing: Move tracing_max_latency into trace_array") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-13tracing: Fix a warning when allocating buffered events failsPetr Pavlu
[ Upstream commit 34209fe83ef8404353f91ab4ea4035dbc9922d04 ] Function trace_buffered_event_disable() produces an unexpected warning when the previous call to trace_buffered_event_enable() fails to allocate pages for buffered events. The situation can occur as follows: * The counter trace_buffered_event_ref is at 0. * The soft mode gets enabled for some event and trace_buffered_event_enable() is called. The function increments trace_buffered_event_ref to 1 and starts allocating event pages. * The allocation fails for some page and trace_buffered_event_disable() is called for cleanup. * Function trace_buffered_event_disable() decrements trace_buffered_event_ref back to 0, recognizes that it was the last use of buffered events and frees all allocated pages. * The control goes back to trace_buffered_event_enable() which returns. The caller of trace_buffered_event_enable() has no information that the function actually failed. * Some time later, the soft mode is disabled for the same event. Function trace_buffered_event_disable() is called. It warns on "WARN_ON_ONCE(!trace_buffered_event_ref)" and returns. Buffered events are just an optimization and can handle failures. Make trace_buffered_event_enable() exit on the first failure and left any cleanup later to when trace_buffered_event_disable() is called. Link: https://lore.kernel.org/all/20231127151248.7232-2-petr.pavlu@suse.com/ Link: https://lkml.kernel.org/r/20231205161736.19663-3-petr.pavlu@suse.com Fixes: 0fc1b09ff1ff ("tracing: Use temp buffer when filtering events") Signed-off-by: Petr Pavlu <petr.pavlu@suse.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-12-13hrtimers: Push pending hrtimers away from outgoing CPU earlierThomas Gleixner
[ Upstream commit 5c0930ccaad5a74d74e8b18b648c5eb21ed2fe94 ] 2b8272ff4a70 ("cpu/hotplug: Prevent self deadlock on CPU hot-unplug") solved the straight forward CPU hotplug deadlock vs. the scheduler bandwidth timer. Yu discovered a more involved variant where a task which has a bandwidth timer started on the outgoing CPU holds a lock and then gets throttled. If the lock required by one of the CPU hotplug callbacks the hotplug operation deadlocks because the unthrottling timer event is not handled on the dying CPU and can only be recovered once the control CPU reaches the hotplug state which pulls the pending hrtimers from the dead CPU. Solve this by pushing the hrtimers away from the dying CPU in the dying callbacks. Nothing can queue a hrtimer on the dying CPU at that point because all other CPUs spin in stop_machine() with interrupts disabled and once the operation is finished the CPU is marked offline. Reported-by: Yu Liao <liaoyu15@huawei.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Liu Tie <liutie4@huawei.com> Link: https://lore.kernel.org/r/87a5rphara.ffs@tglx Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-12-08Revert "workqueue: remove unused cancel_work()"Andrey Grodzovsky
[ Upstream commit 73b4b53276a1d6290cd4f47dbbc885b6e6e59ac6 ] This reverts commit 6417250d3f894e66a68ba1cd93676143f2376a6f. amdpgu need this function in order to prematurly stop pending reset works when another reset work already in progress. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com> Reviewed-by: Lai Jiangshan<jiangshanlai@gmail.com> Reviewed-by: Christian König <christian.koenig@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Stable-dep-of: 91d3d149978b ("r8169: prevent potential deadlock in rtl8169_close") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-12-08lockdep: Fix block chain corruptionPeter Zijlstra
[ Upstream commit bca4104b00fec60be330cd32818dd5c70db3d469 ] Kent reported an occasional KASAN splat in lockdep. Mark then noted: > I suspect the dodgy access is to chain_block_buckets[-1], which hits the last 4 > bytes of the redzone and gets (incorrectly/misleadingly) attributed to > nr_large_chain_blocks. That would mean @size == 0, at which point size_to_bucket() returns -1 and the above happens. alloc_chain_hlocks() has 'size - req', for the first with the precondition 'size >= rq', which allows the 0. This code is trying to split a block, del_chain_block() takes what we need, and add_chain_block() puts back the remainder, except in the above case the remainder is 0 sized and things go sideways. Fixes: 810507fe6fd5 ("locking/lockdep: Reuse freed chain_hlocks entries") Reported-by: Kent Overstreet <kent.overstreet@linux.dev> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Kent Overstreet <kent.overstreet@linux.dev> Link: https://lkml.kernel.org/r/20231121114126.GH8262@noisy.programming.kicks-ass.net Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-28tracing: Have trace_event_file have ref countersSteven Rostedt (Google)
commit bb32500fb9b78215e4ef6ee8b4345c5f5d7eafb4 upstream. The following can crash the kernel: # cd /sys/kernel/tracing # echo 'p:sched schedule' > kprobe_events # exec 5>>events/kprobes/sched/enable # > kprobe_events # exec 5>&- The above commands: 1. Change directory to the tracefs directory 2. Create a kprobe event (doesn't matter what one) 3. Open bash file descriptor 5 on the enable file of the kprobe event 4. Delete the kprobe event (removes the files too) 5. Close the bash file descriptor 5 The above causes a crash! BUG: kernel NULL pointer dereference, address: 0000000000000028 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 6 PID: 877 Comm: bash Not tainted 6.5.0-rc4-test-00008-g2c6b6b1029d4-dirty #186 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:tracing_release_file_tr+0xc/0x50 What happens here is that the kprobe event creates a trace_event_file "file" descriptor that represents the file in tracefs to the event. It maintains state of the event (is it enabled for the given instance?). Opening the "enable" file gets a reference to the event "file" descriptor via the open file descriptor. When the kprobe event is deleted, the file is also deleted from the tracefs system which also frees the event "file" descriptor. But as the tracefs file is still opened by user space, it will not be totally removed until the final dput() is called on it. But this is not true with the event "file" descriptor that is already freed. If the user does a write to or simply closes the file descriptor it will reference the event "file" descriptor that was just freed, causing a use-after-free bug. To solve this, add a ref count to the event "file" descriptor as well as a new flag called "FREED". The "file" will not be freed until the last reference is released. But the FREE flag will be set when the event is removed to prevent any more modifications to that event from happening, even if there's still a reference to the event "file" descriptor. Link: https://lore.kernel.org/linux-trace-kernel/20231031000031.1e705592@gandalf.local.home/ Link: https://lore.kernel.org/linux-trace-kernel/20231031122453.7a48b923@gandalf.local.home Cc: stable@vger.kernel.org Cc: Mark Rutland <mark.rutland@arm.com> Fixes: f5ca233e2e66d ("tracing: Increase trace array ref count on enable and filter files") Reported-by: Beau Belgrave <beaub@linux.microsoft.com> Tested-by: Beau Belgrave <beaub@linux.microsoft.com> Reviewed-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>
2023-11-28kernel/reboot: emergency_restart: Set correct system_stateBenjamin Bara
commit 60466c067927abbcaff299845abd4b7069963139 upstream. As the emergency restart does not call kernel_restart_prepare(), the system_state stays in SYSTEM_RUNNING. Since bae1d3a05a8b, this hinders i2c_in_atomic_xfer_mode() from becoming active, and therefore might lead to avoidable warnings in the restart handlers, e.g.: [ 12.667612] WARNING: CPU: 1 PID: 1 at kernel/rcu/tree_plugin.h:318 rcu_note_context_switch+0x33c/0x6b0 [ 12.676926] Voluntary context switch within RCU read-side critical section! ... [ 12.742376] schedule_timeout from wait_for_completion_timeout+0x90/0x114 [ 12.749179] wait_for_completion_timeout from tegra_i2c_wait_completion+0x40/0x70 ... [ 12.994527] atomic_notifier_call_chain from machine_restart+0x34/0x58 [ 13.001050] machine_restart from panic+0x2a8/0x32c Avoid these by setting the correct system_state. Fixes: bae1d3a05a8b ("i2c: core: remove use of in_atomic()") Cc: stable@vger.kernel.org # v5.2+ Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> Tested-by: Nishanth Menon <nm@ti.com> Signed-off-by: Benjamin Bara <benjamin.bara@skidata.com> Link: https://lore.kernel.org/r/20230327-tegra-pmic-reboot-v7-1-18699d5dcd76@skidata.com Signed-off-by: Lee Jones <lee@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-11-28genirq/generic_chip: Make irq_remove_generic_chip() irqdomain awareHerve Codina
commit 5e7afb2eb7b2a7c81e9f608cbdf74a07606fd1b5 upstream. irq_remove_generic_chip() calculates the Linux interrupt number for removing the handler and interrupt chip based on gc::irq_base as a linear function of the bit positions of set bits in the @msk argument. When the generic chip is present in an irq domain, i.e. created with a call to irq_alloc_domain_generic_chips(), gc::irq_base contains not the base Linux interrupt number. It contains the base hardware interrupt for this chip. It is set to 0 for the first chip in the domain, 0 + N for the next chip, where $N is the number of hardware interrupts per chip. That means the Linux interrupt number cannot be calculated based on gc::irq_base for irqdomain based chips without a domain map lookup, which is currently missing. Rework the code to take the irqdomain case into account and calculate the Linux interrupt number by a irqdomain lookup of the domain specific hardware interrupt number. [ tglx: Massage changelog. Reshuffle the logic and add a proper comment. ] Fixes: cfefd21e693d ("genirq: Add chip suspend and resume callbacks") Signed-off-by: Herve Codina <herve.codina@bootlin.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20231024150335.322282-1-herve.codina@bootlin.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-11-28rcu: kmemleak: Ignore kmemleak false positives when RCU-freeing objectsCatalin Marinas
commit 5f98fd034ca6fd1ab8c91a3488968a0e9caaabf6 upstream. Since the actual slab freeing is deferred when calling kvfree_rcu(), so is the kmemleak_free() callback informing kmemleak of the object deletion. From the perspective of the kvfree_rcu() caller, the object is freed and it may remove any references to it. Since kmemleak does not scan RCU internal data storing the pointer, it will report such objects as leaks during the grace period. Tell kmemleak to ignore such objects on the kvfree_call_rcu() path. Note that the tiny RCU implementation does not have such issue since the objects can be tracked from the rcu_ctrlblk structure. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Reported-by: Christoph Paasch <cpaasch@apple.com> Closes: https://lore.kernel.org/all/F903A825-F05F-4B77-A2B5-7356282FBA2C@apple.com/ Cc: <stable@vger.kernel.org> Tested-by: Christoph Paasch <cpaasch@apple.com> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-11-28PM: hibernate: Clean up sync_read handling in snapshot_write_next()Brian Geffon
commit d08970df1980476f27936e24d452550f3e9e92e1 upstream. In snapshot_write_next(), sync_read is set and unset in three different spots unnecessiarly. As a result there is a subtle bug where the first page after the meta data has been loaded unconditionally sets sync_read to 0. If this first PFN was actually a highmem page, then the returned buffer will be the global "buffer," and the page needs to be loaded synchronously. That is, I'm not sure we can always assume the following to be safe: handle->buffer = get_buffer(&orig_bm, &ca); handle->sync_read = 0; Because get_buffer() can call get_highmem_page_buffer() which can return 'buffer'. The easiest way to address this is just set sync_read before snapshot_write_next() returns if handle->buffer == buffer. Signed-off-by: Brian Geffon <bgeffon@google.com> Fixes: 8357376d3df2 ("[PATCH] swsusp: Improve handling of highmem") Cc: All applicable <stable@vger.kernel.org> [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-11-28PM: hibernate: Use __get_safe_page() rather than touching the listBrian Geffon
commit f0c7183008b41e92fa676406d87f18773724b48b upstream. We found at least one situation where the safe pages list was empty and get_buffer() would gladly try to use a NULL pointer. Signed-off-by: Brian Geffon <bgeffon@google.com> Fixes: 8357376d3df2 ("[PATCH] swsusp: Improve handling of highmem") Cc: All applicable <stable@vger.kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-11-28watchdog: move softlockup_panic back to early_paramKrister Johansen
commit 8b793bcda61f6c3ed4f5b2ded7530ef6749580cb upstream. Setting softlockup_panic from do_sysctl_args() causes it to take effect later in boot. The lockup detector is enabled before SMP is brought online, but do_sysctl_args runs afterwards. If a user wants to set softlockup_panic on boot and have it trigger should a softlockup occur during onlining of the non-boot processors, they could do this prior to commit f117955a2255 ("kernel/watchdog.c: convert {soft/hard}lockup boot parameters to sysctl aliases"). However, after this commit the value of softlockup_panic is set too late to be of help for this type of problem. Restore the prior behavior. Signed-off-by: Krister Johansen <kjlx@templeofstupid.com> Cc: stable@vger.kernel.org Fixes: f117955a2255 ("kernel/watchdog.c: convert {soft/hard}lockup boot parameters to sysctl aliases") Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-11-28audit: don't WARN_ON_ONCE(!current->mm) in audit_exe_compare()Paul Moore
commit 969d90ec212bae4b45bf9d21d7daa30aa6cf055e upstream. eBPF can end up calling into the audit code from some odd places, and some of these places don't have @current set properly so we end up tripping the `WARN_ON_ONCE(!current->mm)` near the top of `audit_exe_compare()`. While the basic `!current->mm` check is good, the `WARN_ON_ONCE()` results in some scary console messages so let's drop that and just do the regular `!current->mm` check to avoid problems. Cc: <stable@vger.kernel.org> Fixes: 47846d51348d ("audit: don't take task_lock() in audit_exe_compare() code path") Reported-by: Artem Savkov <asavkov@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-11-28audit: don't take task_lock() in audit_exe_compare() code pathPaul Moore
commit 47846d51348dd62e5231a83be040981b17c955fa upstream. The get_task_exe_file() function locks the given task with task_lock() which when used inside audit_exe_compare() can cause deadlocks on systems that generate audit records when the task_lock() is held. We resolve this problem with two changes: ignoring those cases where the task being audited is not the current task, and changing our approach to obtaining the executable file struct to not require task_lock(). With the intent of the audit exe filter being to filter on audit events generated by processes started by the specified executable, it makes sense that we would only want to use the exe filter on audit records associated with the currently executing process, e.g. @current. If we are asked to filter records using a non-@current task_struct we can safely ignore the exe filter without negatively impacting the admin's expectations for the exe filter. Knowing that we only have to worry about filtering the currently executing task in audit_exe_compare() we can do away with the task_lock() and call get_mm_exe_file() with @current->mm directly. Cc: <stable@vger.kernel.org> Fixes: 5efc244346f9 ("audit: fix exe_file access in audit_exe_compare") Reported-by: Andreas Steinmetz <anstein99@googlemail.com> Reviewed-by: John Johansen <john.johanse@canonical.com> Reviewed-by: Mateusz Guzik <mjguzik@gmail.com> Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-11-28bpf: Fix precision tracking for BPF_ALU | BPF_TO_BE | BPF_ENDShung-Hsi Yu
commit 291d044fd51f8484066300ee42afecf8c8db7b3a upstream. BPF_END and BPF_NEG has a different specification for the source bit in the opcode compared to other ALU/ALU64 instructions, and is either reserved or use to specify the byte swap endianness. In both cases the source bit does not encode source operand location, and src_reg is a reserved field. backtrack_insn() currently does not differentiate BPF_END and BPF_NEG from other ALU/ALU64 instructions, which leads to r0 being incorrectly marked as precise when processing BPF_ALU | BPF_TO_BE | BPF_END instructions. This commit teaches backtrack_insn() to correctly mark precision for such case. While precise tracking of BPF_NEG and other BPF_END instructions are correct and does not need fixing, this commit opt to process all BPF_NEG and BPF_END instructions within the same if-clause to better align with current convention used in the verifier (e.g. check_alu_op). Fixes: b5dc0163d8fd ("bpf: precise scalar_value tracking") Cc: stable@vger.kernel.org Reported-by: Mohamed Mahmoud <mmahmoud@redhat.com> Closes: https://lore.kernel.org/r/87jzrrwptf.fsf@toke.dk Tested-by: Toke Høiland-Jørgensen <toke@redhat.com> Tested-by: Tao Lyu <tao.lyu@epfl.ch> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com> Link: https://lore.kernel.org/r/20231102053913.12004-2-shung-hsi.yu@suse.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-11-28bpf: Fix check_stack_write_fixed_off() to correctly spill immHao Sun
commit 811c363645b33e6e22658634329e95f383dfc705 upstream. In check_stack_write_fixed_off(), imm value is cast to u32 before being spilled to the stack. Therefore, the sign information is lost, and the range information is incorrect when load from the stack again. For the following prog: 0: r2 = r10 1: *(u64*)(r2 -40) = -44 2: r0 = *(u64*)(r2 - 40) 3: if r0 s<= 0xa goto +2 4: r0 = 1 5: exit 6: r0 = 0 7: exit The verifier gives: func#0 @0 0: R1=ctx(off=0,imm=0) R10=fp0 0: (bf) r2 = r10 ; R2_w=fp0 R10=fp0 1: (7a) *(u64 *)(r2 -40) = -44 ; R2_w=fp0 fp-40_w=4294967252 2: (79) r0 = *(u64 *)(r2 -40) ; R0_w=4294967252 R2_w=fp0 fp-40_w=4294967252 3: (c5) if r0 s< 0xa goto pc+2 mark_precise: frame0: last_idx 3 first_idx 0 subseq_idx -1 mark_precise: frame0: regs=r0 stack= before 2: (79) r0 = *(u64 *)(r2 -40) 3: R0_w=4294967252 4: (b7) r0 = 1 ; R0_w=1 5: (95) exit verification time 7971 usec stack depth 40 processed 6 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0 So remove the incorrect cast, since imm field is declared as s32, and __mark_reg_known() takes u64, so imm would be correctly sign extended by compiler. Fixes: ecdf985d7615 ("bpf: track immediate values written to stack by BPF_ST instruction") Cc: stable@vger.kernel.org Signed-off-by: Hao Sun <sunhao.th@gmail.com> Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/r/20231101-fix-check-stack-write-v3-1-f05c2b1473d5@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-11-28kgdb: Flush console before entering kgdb on panicDouglas Anderson
[ Upstream commit dd712d3d45807db9fcae28a522deee85c1f2fde6 ] When entering kdb/kgdb on a kernel panic, it was be observed that the console isn't flushed before the `kdb` prompt came up. Specifically, when using the buddy lockup detector on arm64 and running: echo HARDLOCKUP > /sys/kernel/debug/provoke-crash/DIRECT I could see: [ 26.161099] lkdtm: Performing direct entry HARDLOCKUP [ 32.499881] watchdog: Watchdog detected hard LOCKUP on cpu 6 [ 32.552865] Sending NMI from CPU 5 to CPUs 6: [ 32.557359] NMI backtrace for cpu 6 ... [backtrace for cpu 6] ... [ 32.558353] NMI backtrace for cpu 5 ... [backtrace for cpu 5] ... [ 32.867471] Sending NMI from CPU 5 to CPUs 0-4,7: [ 32.872321] NMI backtrace forP cpuANC: Hard LOCKUP Entering kdb (current=..., pid 0) on processor 5 due to Keyboard Entry [5]kdb> As you can see, backtraces for the other CPUs start printing and get interleaved with the kdb PANIC print. Let's replicate the commands to flush the console in the kdb panic entry point to avoid this. Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20230822131945.1.I5b460ae8f954e4c4f628a373d6e74713c06dd26f@changeid Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-28crypto: pcrypt - Fix hungtask for PADATA_RESETLu Jialin
[ Upstream commit 8f4f68e788c3a7a696546291258bfa5fdb215523 ] We found a hungtask bug in test_aead_vec_cfg as follows: INFO: task cryptomgr_test:391009 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Call trace: __switch_to+0x98/0xe0 __schedule+0x6c4/0xf40 schedule+0xd8/0x1b4 schedule_timeout+0x474/0x560 wait_for_common+0x368/0x4e0 wait_for_completion+0x20/0x30 wait_for_completion+0x20/0x30 test_aead_vec_cfg+0xab4/0xd50 test_aead+0x144/0x1f0 alg_test_aead+0xd8/0x1e0 alg_test+0x634/0x890 cryptomgr_test+0x40/0x70 kthread+0x1e0/0x220 ret_from_fork+0x10/0x18 Kernel panic - not syncing: hung_task: blocked tasks For padata_do_parallel, when the return err is 0 or -EBUSY, it will call wait_for_completion(&wait->completion) in test_aead_vec_cfg. In normal case, aead_request_complete() will be called in pcrypt_aead_serial and the return err is 0 for padata_do_parallel. But, when pinst->flags is PADATA_RESET, the return err is -EBUSY for padata_do_parallel, and it won't call aead_request_complete(). Therefore, test_aead_vec_cfg will hung at wait_for_completion(&wait->completion), which will cause hungtask. The problem comes as following: (padata_do_parallel) | rcu_read_lock_bh(); | err = -EINVAL; | (padata_replace) | pinst->flags |= PADATA_RESET; err = -EBUSY | if (pinst->flags & PADATA_RESET) | rcu_read_unlock_bh() | return err In order to resolve the problem, we replace the return err -EBUSY with -EAGAIN, which means parallel_data is changing, and the caller should call it again. v3: remove retry and just change the return err. v2: introduce padata_try_do_parallel() in pcrypt_aead_encrypt and pcrypt_aead_decrypt to solve the hungtask. Signed-off-by: Lu Jialin <lujialin4@huawei.com> Signed-off-by: Guo Zihua <guozihua@huawei.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-28bpf: Detect IP == ksym.end as part of BPF programKumar Kartikeya Dwivedi
[ Upstream commit 66d9111f3517f85ef2af0337ece02683ce0faf21 ] Now that bpf_throw kfunc is the first such call instruction that has noreturn semantics within the verifier, this also kicks in dead code elimination in unprecedented ways. For one, any instruction following a bpf_throw call will never be marked as seen. Moreover, if a callchain ends up throwing, any instructions after the call instruction to the eventually throwing subprog in callers will also never be marked as seen. The tempting way to fix this would be to emit extra 'int3' instructions which bump the jited_len of a program, and ensure that during runtime when a program throws, we can discover its boundaries even if the call instruction to bpf_throw (or to subprogs that always throw) is emitted as the final instruction in the program. An example of such a program would be this: do_something(): ... r0 = 0 exit foo(): r1 = 0 call bpf_throw r0 = 0 exit bar(cond): if r1 != 0 goto pc+2 call do_something exit call foo r0 = 0 // Never seen by verifier exit // main(ctx): r1 = ... call bar r0 = 0 exit Here, if we do end up throwing, the stacktrace would be the following: bpf_throw foo bar main In bar, the final instruction emitted will be the call to foo, as such, the return address will be the subsequent instruction (which the JIT emits as int3 on x86). This will end up lying outside the jited_len of the program, thus, when unwinding, we will fail to discover the return address as belonging to any program and end up in a panic due to the unreliable stack unwinding of BPF programs that we never expect. To remedy this case, make bpf_prog_ksym_find treat IP == ksym.end as part of the BPF program, so that is_bpf_text_address returns true when such a case occurs, and we are able to unwind reliably when the final instruction ends up being a call instruction. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20230912233214.1518551-12-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-28perf/core: Bail out early if the request AUX area is out of boundShuai Xue
[ Upstream commit 54aee5f15b83437f23b2b2469bcf21bdd9823916 ] When perf-record with a large AUX area, e.g 4GB, it fails with: #perf record -C 0 -m ,4G -e arm_spe_0// -- sleep 1 failed to mmap with 12 (Cannot allocate memory) and it reveals a WARNING with __alloc_pages(): ------------[ cut here ]------------ WARNING: CPU: 44 PID: 17573 at mm/page_alloc.c:5568 __alloc_pages+0x1ec/0x248 Call trace: __alloc_pages+0x1ec/0x248 __kmalloc_large_node+0xc0/0x1f8 __kmalloc_node+0x134/0x1e8 rb_alloc_aux+0xe0/0x298 perf_mmap+0x440/0x660 mmap_region+0x308/0x8a8 do_mmap+0x3c0/0x528 vm_mmap_pgoff+0xf4/0x1b8 ksys_mmap_pgoff+0x18c/0x218 __arm64_sys_mmap+0x38/0x58 invoke_syscall+0x50/0x128 el0_svc_common.constprop.0+0x58/0x188 do_el0_svc+0x34/0x50 el0_svc+0x34/0x108 el0t_64_sync_handler+0xb8/0xc0 el0t_64_sync+0x1a4/0x1a8 'rb->aux_pages' allocated by kcalloc() is a pointer array which is used to maintains AUX trace pages. The allocated page for this array is physically contiguous (and virtually contiguous) with an order of 0..MAX_ORDER. If the size of pointer array crosses the limitation set by MAX_ORDER, it reveals a WARNING. So bail out early with -ENOMEM if the request AUX area is out of bound, e.g.: #perf record -C 0 -m ,4G -e arm_spe_0// -- sleep 1 failed to mmap with 12 (Cannot allocate memory) Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-28locking/ww_mutex/test: Fix potential workqueue corruptionJohn Stultz
[ Upstream commit bccdd808902f8c677317cec47c306e42b93b849e ] In some cases running with the test-ww_mutex code, I was seeing odd behavior where sometimes it seemed flush_workqueue was returning before all the work threads were finished. Often this would cause strange crashes as the mutexes would be freed while they were being used. Looking at the code, there is a lifetime problem as the controlling thread that spawns the work allocates the "struct stress" structures that are passed to the workqueue threads. Then when the workqueue threads are finished, they free the stress struct that was passed to them. Unfortunately the workqueue work_struct node is in the stress struct. Which means the work_struct is freed before the work thread returns and while flush_workqueue is waiting. It seems like a better idea to have the controlling thread both allocate and free the stress structures, so that we can be sure we don't corrupt the workqueue by freeing the structure prematurely. So this patch reworks the test to do so, and with this change I no longer see the early flush_workqueue returns. Signed-off-by: John Stultz <jstultz@google.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20230922043616.19282-3-jstultz@google.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-20tracing/kprobes: Fix the order of argument descriptionsYujie Liu
[ Upstream commit f032c53bea6d2057c14553832d846be2f151cfb2 ] The order of descriptions should be consistent with the argument list of the function, so "kretprobe" should be the second one. int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe, const char *name, const char *loc, ...) Link: https://lore.kernel.org/all/20231031041305.3363712-1-yujie.liu@intel.com/ Fixes: 2a588dd1d5d6 ("tracing: Add kprobe event command generation functions") Suggested-by: Mukesh Ojha <quic_mojha@quicinc.com> Signed-off-by: Yujie Liu <yujie.liu@intel.com> Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-20livepatch: Fix missing newline character in klp_resolve_symbols()Zheng Yejian
[ Upstream commit 67e18e132f0fd738f8c8cac3aa1420312073f795 ] Without the newline character, the log may not be printed immediately after the error occurs. Fixes: ca376a937486 ("livepatch: Prevent module-specific KLP rela sections from referencing vmlinux symbols") Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20230914072644.4098857-1-zhengyejian1@huawei.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-20padata: Fix refcnt handling in padata_free_shell()WangJinchao
[ Upstream commit 7ddc21e317b360c3444de3023bcc83b85fabae2f ] In a high-load arm64 environment, the pcrypt_aead01 test in LTP can lead to system UAF (Use-After-Free) issues. Due to the lengthy analysis of the pcrypt_aead01 function call, I'll describe the problem scenario using a simplified model: Suppose there's a user of padata named `user_function` that adheres to the padata requirement of calling `padata_free_shell` after `serial()` has been invoked, as demonstrated in the following code: ```c struct request { struct padata_priv padata; struct completion *done; }; void parallel(struct padata_priv *padata) { do_something(); } void serial(struct padata_priv *padata) { struct request *request = container_of(padata, struct request, padata); complete(request->done); } void user_function() { DECLARE_COMPLETION(done) padata->parallel = parallel; padata->serial = serial; padata_do_parallel(); wait_for_completion(&done); padata_free_shell(); } ``` In the corresponding padata.c file, there's the following code: ```c static void padata_serial_worker(struct work_struct *serial_work) { ... cnt = 0; while (!list_empty(&local_list)) { ... padata->serial(padata); cnt++; } local_bh_enable(); if (refcount_sub_and_test(cnt, &pd->refcnt)) padata_free_pd(pd); } ``` Because of the high system load and the accumulation of unexecuted softirq at this moment, `local_bh_enable()` in padata takes longer to execute than usual. Subsequently, when accessing `pd->refcnt`, `pd` has already been released by `padata_free_shell()`, resulting in a UAF issue with `pd->refcnt`. The fix is straightforward: add `refcount_dec_and_test` before calling `padata_free_pd` in `padata_free_shell`. Fixes: 07928d9bfc81 ("padata: Remove broken queue flushing") Signed-off-by: WangJinchao <wangjinchao@xfusion.com> Acked-by: Daniel Jordan <daniel.m.jordan@oracle.com> Acked-by: Daniel Jordan <daniel.m.jordan@oracle.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-20padata: Convert from atomic_t to refcount_t on parallel_data->refcntXiyu Yang
[ Upstream commit d5ee8e750c9449e9849a09ce6fb6b8adeaa66adc ] refcount_t type and corresponding API can protect refcounters from accidental underflow and overflow and further use-after-free situations. Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com> Acked-by: Daniel Jordan <daniel.m.jordan@oracle.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Stable-dep-of: 7ddc21e317b3 ("padata: Fix refcnt handling in padata_free_shell()") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-20genirq/matrix: Exclude managed interrupts in irq_matrix_allocated()Chen Yu
[ Upstream commit a0b0bad10587ae2948a7c36ca4ffc206007fbcf3 ] When a CPU is about to be offlined, x86 validates that all active interrupts which are targeted to this CPU can be migrated to the remaining online CPUs. If not, the offline operation is aborted. The validation uses irq_matrix_allocated() to retrieve the number of vectors which are allocated on the outgoing CPU. The returned number of allocated vectors includes also vectors which are associated to managed interrupts. That's overaccounting because managed interrupts are: - not migrated when the affinity mask of the interrupt targets only the outgoing CPU - migrated to another CPU, but in that case the vector is already pre-allocated on the potential target CPUs and must not be taken into account. As a consequence the check whether the remaining online CPUs have enough capacity for migrating the allocated vectors from the outgoing CPU might fail incorrectly. Let irq_matrix_allocated() return only the number of allocated non-managed interrupts to make this validation check correct. [ tglx: Amend changelog and fixup kernel-doc comment ] Fixes: 2f75d9e1c905 ("genirq: Implement bitmap matrix allocator") Reported-by: Wendy Wang <wendy.wang@intel.com> Signed-off-by: Chen Yu <yu.c.chen@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20231020072522.557846-1-yu.c.chen@intel.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-20futex: Don't include process MM in futex key on no-MMUBen Wolsieffer
[ Upstream commit c73801ae4f22b390228ebf471d55668e824198b6 ] On no-MMU, all futexes are treated as private because there is no need to map a virtual address to physical to match the futex across processes. This doesn't quite work though, because private futexes include the current process's mm_struct as part of their key. This makes it impossible for one process to wake up a shared futex being waited on in another process. Fix this bug by excluding the mm_struct from the key. With a single address space, the futex address is already a unique key. Fixes: 784bdf3bb694 ("futex: Assume all mappings are private on !MMU systems") Signed-off-by: Ben Wolsieffer <ben.wolsieffer@hefring.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Darren Hart <dvhart@infradead.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: André Almeida <andrealmeid@igalia.com> Link: https://lore.kernel.org/r/20231019204548.1236437-2-ben.wolsieffer@hefring.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-20sched/uclamp: Ignore (util == 0) optimization in feec() when p_util_max = 0Qais Yousef
[ Upstream commit 23c9519def98ee0fa97ea5871535e9b136f522fc ] find_energy_efficient_cpu() bails out early if effective util of the task is 0 as the delta at this point will be zero and there's nothing for EAS to do. When uclamp is being used, this could lead to wrong decisions when uclamp_max is set to 0. In this case the task is capped to performance point 0, but it is actually running and consuming energy and we can benefit from EAS energy calculations. Rework the condition so that it bails out when both util and uclamp_min are 0. We can do that without needing to use uclamp_task_util(); remove it. Fixes: d81304bc6193 ("sched/uclamp: Cater for uclamp in find_energy_efficient_cpu()'s early exit condition") Signed-off-by: Qais Yousef (Google) <qyousef@layalina.io> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20230916232955.2099394-3-qyousef@layalina.io Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-08perf/core: Fix potential NULL derefPeter Zijlstra
commit a71ef31485bb51b846e8db8b3a35e432cc15afb5 upstream. Smatch is awesome. Fixes: 32671e3799ca ("perf: Disallow mis-matched inherited group reads") Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-11-08tracing/kprobes: Fix the description of variable length argumentsYujie Liu
commit e0f831836cead677fb07d54bd6bf499df35640c2 upstream. Fix the following kernel-doc warnings: kernel/trace/trace_kprobe.c:1029: warning: Excess function parameter 'args' description in '__kprobe_event_gen_cmd_start' kernel/trace/trace_kprobe.c:1097: warning: Excess function parameter 'args' description in '__kprobe_event_add_fields' Refer to the usage of variable length arguments elsewhere in the kernel code, "@..." is the proper way to express it in the description. Link: https://lore.kernel.org/all/20231027041315.2613166-1-yujie.liu@intel.com/ Fixes: 2a588dd1d5d6 ("tracing: Add kprobe event command generation functions") Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202310190437.paI6LYJF-lkp@intel.com/ Signed-off-by: Yujie Liu <yujie.liu@intel.com> Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com> 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>
2023-10-25perf: Disallow mis-matched inherited group readsPeter Zijlstra
commit 32671e3799ca2e4590773fd0e63aaa4229e50c06 upstream. Because group consistency is non-atomic between parent (filedesc) and children (inherited) events, it is possible for PERF_FORMAT_GROUP read() to try and sum non-matching counter groups -- with non-sensical results. Add group_generation to distinguish the case where a parent group removes and adds an event and thus has the same number, but a different configuration of events as inherited groups. This became a problem when commit fa8c269353d5 ("perf/core: Invert perf_read_group() loops") flipped the order of child_list and sibling_list. Previously it would iterate the group (sibling_list) first, and for each sibling traverse the child_list. In this order, only the group composition of the parent is relevant. By flipping the order the group composition of the child (inherited) events becomes an issue and the mis-match in group composition becomes evident. That said; even prior to this commit, while reading of a group that is not equally inherited was not broken, it still made no sense. (Ab)use ECHILD as error return to indicate issues with child process group composition. Fixes: fa8c269353d5 ("perf/core: Invert perf_read_group() loops") Reported-by: Budimir Markovic <markovicbudimir@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20231018115654.GK33217@noisy.programming.kicks-ass.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-10-25tracing: relax trace_event_eval_update() execution with cond_resched()Clément Léger
[ Upstream commit 23cce5f25491968b23fb9c399bbfb25f13870cd9 ] When kernel is compiled without preemption, the eval_map_work_func() (which calls trace_event_eval_update()) will not be preempted up to its complete execution. This can actually cause a problem since if another CPU call stop_machine(), the call will have to wait for the eval_map_work_func() function to finish executing in the workqueue before being able to be scheduled. This problem was observe on a SMP system at boot time, when the CPU calling the initcalls executed clocksource_done_booting() which in the end calls stop_machine(). We observed a 1 second delay because one CPU was executing eval_map_work_func() and was not preempted by the stop_machine() task. Adding a call to cond_resched() in trace_event_eval_update() allows other tasks to be executed and thus continue working asynchronously like before without blocking any pending task at boot time. Link: https://lore.kernel.org/linux-trace-kernel/20230929191637.416931-1-cleger@rivosinc.com Cc: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Clément Léger <cleger@rivosinc.com> Tested-by: Atish Patra <atishp@rivosinc.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-10-25cgroup: Remove duplicates in cgroup v1 tasks fileMichal Koutný
commit 1ca0b605150501b7dc59f3016271da4eb3e96fce upstream. One PID may appear multiple times in a preloaded pidlist. (Possibly due to PID recycling but we have reports of the same task_struct appearing with different PIDs, thus possibly involving transfer of PID via de_thread().) Because v1 seq_file iterator uses PIDs as position, it leads to a message: > seq_file: buggy .next function kernfs_seq_next did not update position index Conservative and quick fix consists of removing duplicates from `tasks` file (as opposed to removing pidlists altogether). It doesn't affect correctness (it's sufficient to show a PID once), performance impact would be hidden by unconditional sorting of the pidlist already in place (asymptotically). Link: https://lore.kernel.org/r/20230823174804.23632-1-mkoutny@suse.com/ Suggested-by: Firo Yang <firo.yang@suse.com> Signed-off-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-10-25workqueue: Override implicit ordered attribute in ↵Waiman Long
workqueue_apply_unbound_cpumask() [ Upstream commit ca10d851b9ad0338c19e8e3089e24d565ebfffd7 ] Commit 5c0338c68706 ("workqueue: restore WQ_UNBOUND/max_active==1 to be ordered") enabled implicit ordered attribute to be added to WQ_UNBOUND workqueues with max_active of 1. This prevented the changing of attributes to these workqueues leading to fix commit 0a94efb5acbb ("workqueue: implicit ordered attribute should be overridable"). However, workqueue_apply_unbound_cpumask() was not updated at that time. So sysfs changes to wq_unbound_cpumask has no effect on WQ_UNBOUND workqueues with implicit ordered attribute. Since not all WQ_UNBOUND workqueues are visible on sysfs, we are not able to make all the necessary cpumask changes even if we iterates all the workqueue cpumasks in sysfs and changing them one by one. Fix this problem by applying the corresponding change made to apply_workqueue_attrs_locked() in the fix commit to workqueue_apply_unbound_cpumask(). Fixes: 5c0338c68706 ("workqueue: restore WQ_UNBOUND/max_active==1 to be ordered") Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-10-10ring-buffer: Fix bytes info in per_cpu buffer statsZheng Yejian
[ Upstream commit 45d99ea451d0c30bfd4864f0fe485d7dac014902 ] The 'bytes' info in file 'per_cpu/cpu<X>/stats' means the number of bytes in cpu buffer that have not been consumed. However, currently after consuming data by reading file 'trace_pipe', the 'bytes' info was not changed as expected. # cat per_cpu/cpu0/stats entries: 0 overrun: 0 commit overrun: 0 bytes: 568 <--- 'bytes' is problematical !!! oldest event ts: 8651.371479 now ts: 8653.912224 dropped events: 0 read events: 8 The root cause is incorrect stat on cpu_buffer->read_bytes. To fix it: 1. When stat 'read_bytes', account consumed event in rb_advance_reader(); 2. When stat 'entries_bytes', exclude the discarded padding event which is smaller than minimum size because it is invisible to reader. Then use rb_page_commit() instead of BUF_PAGE_SIZE at where accounting for page-based read/remove/overrun. Also correct the comments of ring_buffer_bytes_cpu() in this patch. Link: https://lore.kernel.org/linux-trace-kernel/20230921125425.1708423-1-zhengyejian1@huawei.com Cc: stable@vger.kernel.org Fixes: c64e148a3be3 ("trace: Add ring buffer stats to measure rate of 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>
2023-10-10ring-buffer: remove obsolete comment for free_buffer_page()Vlastimil Babka
[ Upstream commit a98151ad53b53f010ee364ec2fd06445b328578b ] The comment refers to mm/slob.c which is being removed. It comes from commit ed56829cb319 ("ring_buffer: reset buffer page when freeing") and according to Steven the borrowed code was a page mapcount and mapping reset, which was later removed by commit e4c2ce82ca27 ("ring_buffer: allocate buffer page pointer"). Thus the comment is not accurate anyway, remove it. Link: https://lore.kernel.org/linux-trace-kernel/20230315142446.27040-1-vbabka@suse.cz Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Reported-by: Mike Rapoport <mike.rapoport@gmail.com> Suggested-by: Steven Rostedt (Google) <rostedt@goodmis.org> Fixes: e4c2ce82ca27 ("ring_buffer: allocate buffer page pointer") Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Stable-dep-of: 45d99ea451d0 ("ring-buffer: Fix bytes info in per_cpu buffer stats") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-10-10ring-buffer: Update "shortest_full" in pollingSteven Rostedt (Google)
commit 1e0cb399c7653462d9dadf8ab9425337c355d358 upstream. It was discovered that the ring buffer polling was incorrectly stating that read would not block, but that's because polling did not take into account that reads will block if the "buffer-percent" was set. Instead, the ring buffer polling would say reads would not block if there was any data in the ring buffer. This was incorrect behavior from a user space point of view. This was fixed by commit 42fb0a1e84ff by having the polling code check if the ring buffer had more data than what the user specified "buffer percent" had. The problem now is that the polling code did not register itself to the writer that it wanted to wait for a specific "full" value of the ring buffer. The result was that the writer would wake the polling waiter whenever there was a new event. The polling waiter would then wake up, see that there's not enough data in the ring buffer to notify user space and then go back to sleep. The next event would wake it up again. Before the polling fix was added, the code would wake up around 100 times for a hackbench 30 benchmark. After the "fix", due to the constant waking of the writer, it would wake up over 11,0000 times! It would never leave the kernel, so the user space behavior was still "correct", but this definitely is not the desired effect. To fix this, have the polling code add what it's waiting for to the "shortest_full" variable, to tell the writer not to wake it up if the buffer is not as full as it expects to be. Note, after this fix, it appears that the waiter is now woken up around 2x the times it was before (~200). This is a tremendous improvement from the 11,000 times, but I will need to spend some time to see why polling is more aggressive in its wakeups than the read blocking code. Link: https://lore.kernel.org/linux-trace-kernel/20230929180113.01c2cae3@rorschach.local.home Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Fixes: 42fb0a1e84ff ("tracing/ring-buffer: Have polling block on watermark") Reported-by: Julia Lawall <julia.lawall@inria.fr> Tested-by: Julia Lawall <julia.lawall@inria.fr> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-10-10sched/cpuacct: Optimize away RCU read lockChengming Zhou
commit dc6e0818bc9a0336d9accf3ea35d146d72aa7a18 upstream. Since cpuacct_charge() is called from the scheduler update_curr(), we must already have rq lock held, then the RCU read lock can be optimized away. And do the same thing in it's wrapper cgroup_account_cputime(), but we can't use lockdep_assert_rq_held() there, which defined in kernel/sched/sched.h. Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20220220051426.5274-2-zhouchengming@bytedance.com [OP: adjusted lockdep_assert_rq_held() -> lockdep_assert_held()] Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-10-10sched/cpuacct: Fix charge percpu cpuusageChengming Zhou
commit 248cc9993d1cc12b8e9ed716cc3fc09f6c3517dd upstream. The cpuacct_account_field() is always called by the current task itself, so it's ok to use __this_cpu_add() to charge the tick time. But cpuacct_charge() maybe called by update_curr() in load_balance() on a random CPU, different from the CPU on which the task is running. So __this_cpu_add() will charge that cputime to a random incorrect CPU. Fixes: 73e6aafd9ea8 ("sched/cpuacct: Simplify the cpuacct code") Reported-by: Minye Zhu <zhuminye@bytedance.com> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20220220051426.5274-1-zhouchengming@bytedance.com Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-10-10sched/cpuacct: Fix user/system in shown cpuacct.usage*Andrey Ryabinin
commit dd02d4234c9a2214a81c57a16484304a1a51872a upstream. cpuacct has 2 different ways of accounting and showing user and system times. The first one uses cpuacct_account_field() to account times and cpuacct.stat file to expose them. And this one seems to work ok. The second one is uses cpuacct_charge() function for accounting and set of cpuacct.usage* files to show times. Despite some attempts to fix it in the past it still doesn't work. Sometimes while running KVM guest the cpuacct_charge() accounts most of the guest time as system time. This doesn't match with user&system times shown in cpuacct.stat or proc/<pid>/stat. Demonstration: # git clone https://github.com/aryabinin/kvmsample # make # mkdir /sys/fs/cgroup/cpuacct/test # echo $$ > /sys/fs/cgroup/cpuacct/test/tasks # ./kvmsample & # for i in {1..5}; do cat /sys/fs/cgroup/cpuacct/test/cpuacct.usage_sys; sleep 1; done 1976535645 2979839428 3979832704 4983603153 5983604157 Use cpustats accounted in cpuacct_account_field() as the source of user/sys times for cpuacct.usage* files. Make cpuacct_charge() to account only summary execution time. Fixes: d740037fac70 ("sched/cpuacct: Split usage accounting into user_usage and sys_usage") Signed-off-by: Andrey Ryabinin <arbn@yandex-team.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20211115164607.23784-3-arbn@yandex-team.com [OP: adjusted context for v5.10] Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-10-10ring-buffer: Do not attempt to read past "commit"Steven Rostedt (Google)
[ Upstream commit 95a404bd60af6c4d9d8db01ad14fe8957ece31ca ] When iterating over the ring buffer while the ring buffer is active, the writer can corrupt the reader. There's barriers to help detect this and handle it, but that code missed the case where the last event was at the very end of the page and has only 4 bytes left. The checks to detect the corruption by the writer to reads needs to see the length of the event. If the length in the first 4 bytes is zero then the length is stored in the second 4 bytes. But if the writer is in the process of updating that code, there's a small window where the length in the first 4 bytes could be zero even though the length is only 4 bytes. That will cause rb_event_length() to read the next 4 bytes which could happen to be off the allocated page. To protect against this, fail immediately if the next event pointer is less than 8 bytes from the end of the commit (last byte of data), as all events must be a minimum of 8 bytes anyway. Link: https://lore.kernel.org/all/20230905141245.26470-1-Tze-nan.Wu@mediatek.com/ Link: https://lore.kernel.org/linux-trace-kernel/20230907122820.0899019c@gandalf.local.home Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Reported-by: Tze-nan Wu <Tze-nan.Wu@mediatek.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-10-10ring-buffer: Avoid softlockup in ring_buffer_resize()Zheng Yejian
[ Upstream commit f6bd2c92488c30ef53b5bd80c52f0a7eee9d545a ] When user resize all trace ring buffer through file 'buffer_size_kb', then in ring_buffer_resize(), kernel allocates buffer pages for each cpu in a loop. If the kernel preemption model is PREEMPT_NONE and there are many cpus and there are many buffer pages to be allocated, it may not give up cpu for a long time and finally cause a softlockup. To avoid it, call cond_resched() after each cpu buffer allocation. Link: https://lore.kernel.org/linux-trace-kernel/20230906081930.3939106-1-zhengyejian1@huawei.com Cc: <mhiramat@kernel.org> 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>