user/sven/linux.git/kernel/tracepoint.c, branch v5.9.1

Merge tag 'trace-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2019-07-18T18:51:00Z

Pull tracing updates from Steven Rostedt: "The main changes in this release include: - Add user space specific memory reading for kprobes - Allow kprobes to be executed earlier in boot The rest are mostly just various clean ups and small fixes" * tag 'trace-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (33 commits) tracing: Make trace_get_fields() global tracing: Let filter_assign_type() detect FILTER_PTR_STRING tracing: Pass type into tracing_generic_entry_update() ftrace/selftest: Test if set_event/ftrace_pid exists before writing ftrace/selftests: Return the skip code when tracing directory not configured in kernel tracing/kprobe: Check registered state using kprobe tracing/probe: Add trace_event_call accesses APIs tracing/probe: Add probe event name and group name accesses APIs tracing/probe: Add trace flag access APIs for trace_probe tracing/probe: Add trace_event_file access APIs for trace_probe tracing/probe: Add trace_event_call register API for trace_probe tracing/probe: Add trace_probe init and free functions tracing/uprobe: Set print format when parsing command tracing/kprobe: Set print format right after parsed command kprobes: Fix to init kprobes in subsys_initcall tracepoint: Use struct_size() in kmalloc() ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS ftrace: Enable trampoline when rec count returns back to one tracing/kprobe: Do not run kprobe boot tests if kprobe_event is on cmdline tracing: Make a separate config for trace event self tests ...

tracepoint: Use struct_size() in kmalloc()

2019-06-18T01:13:32Z

One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct tp_probes { ... struct tracepoint_func probes[0]; }; instance = kmalloc(sizeof(sizeof(struct tp_probes) + sizeof(struct tracepoint_func) * count, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kmalloc(struct_size(instance, probes, count) GFP_KERNEL); This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva Signed-off-by: Steven Rostedt (VMware)

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

2019-05-30T18:26:35Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Richard Fontana Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman

tracing: Replace synchronize_sched() and call_rcu_sched()

2018-11-27T17:21:41Z

Now that synchronize_rcu() waits for preempt-disable regions of code as well as RCU read-side critical sections, synchronize_sched() can be replaced by synchronize_rcu(). Similarly, call_rcu_sched() can be replaced by call_rcu(). This commit therefore makes these changes. Signed-off-by: Paul E. McKenney Cc: Ingo Molnar Cc: Acked-by: Steven Rostedt (VMware)

tracepoint: Fix tracepoint array element size mismatch

2018-10-17T19:35:29Z

commit 46e0c9be206f ("kernel: tracepoints: add support for relative references") changes the layout of the __tracepoint_ptrs section on architectures supporting relative references. However, it does so without turning struct tracepoint * const into const int elsewhere in the tracepoint code, which has the following side-effect: Setting mod->num_tracepoints is done in by module.c: mod->tracepoints_ptrs = section_objs(info, "__tracepoints_ptrs", sizeof(*mod->tracepoints_ptrs), &mod->num_tracepoints); Basically, since sizeof(*mod->tracepoints_ptrs) is a pointer size (rather than sizeof(int)), num_tracepoints is erroneously set to half the size it should be on 64-bit arch. So a module with an odd number of tracepoints misses the last tracepoint due to effect of integer division. So in the module going notifier: for_each_tracepoint_range(mod->tracepoints_ptrs, mod->tracepoints_ptrs + mod->num_tracepoints, tp_module_going_check_quiescent, NULL); the expression (mod->tracepoints_ptrs + mod->num_tracepoints) actually evaluates to something within the bounds of the array, but miss the last tracepoint if the number of tracepoints is odd on 64-bit arch. Fix this by introducing a new typedef: tracepoint_ptr_t, which is either "const int" on architectures that have PREL32 relocations, or "struct tracepoint * const" on architectures that does not have this feature. Also provide a new tracepoint_ptr_defer() static inline to encapsulate deferencing this type rather than duplicate code and ugly idefs within the for_each_tracepoint_range() implementation. This issue appears in 4.19-rc kernels, and should ideally be fixed before the end of the rc cycle. Acked-by: Ard Biesheuvel Acked-by: Jessica Yu Link: http://lkml.kernel.org/r/20181013191050.22389-1-mathieu.desnoyers@efficios.com Link: http://lkml.kernel.org/r/20180704083651.24360-7-ard.biesheuvel@linaro.org Cc: Michael Ellerman Cc: Ingo Molnar Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Benjamin Herrenschmidt Cc: Bjorn Helgaas Cc: Catalin Marinas Cc: James Morris Cc: James Morris Cc: Josh Poimboeuf Cc: Kees Cook Cc: Nicolas Pitre Cc: Paul Mackerras Cc: Petr Mladek Cc: Russell King Cc: "Serge E. Hallyn" Cc: Sergey Senozhatsky Cc: Thomas Garnier Cc: Thomas Gleixner Cc: Will Deacon Cc: Andrew Morton Cc: Linus Torvalds Cc: Greg Kroah-Hartman Signed-off-by: Mathieu Desnoyers Signed-off-by: Steven Rostedt (VMware)

kernel: tracepoints: add support for relative references

2018-08-22T17:52:47Z

To avoid the need for relocating absolute references to tracepoint structures at boot time when running relocatable kernels (which may take a disproportionate amount of space), add the option to emit these tables as relative references instead. Link: http://lkml.kernel.org/r/20180704083651.24360-7-ard.biesheuvel@linaro.org Acked-by: Michael Ellerman Acked-by: Ingo Molnar Acked-by: Steven Rostedt (VMware) Signed-off-by: Ard Biesheuvel Cc: Arnd Bergmann Cc: Benjamin Herrenschmidt Cc: Bjorn Helgaas Cc: Catalin Marinas Cc: James Morris Cc: James Morris Cc: Jessica Yu Cc: Josh Poimboeuf Cc: Kees Cook Cc: Nicolas Pitre Cc: Paul Mackerras Cc: Petr Mladek Cc: Russell King Cc: "Serge E. Hallyn" Cc: Sergey Senozhatsky Cc: Thomas Garnier Cc: Thomas Gleixner Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

tracepoints: Free early tracepoints after RCU is initialized

2018-08-10T19:32:53Z

When enabling trace events via the kernel command line, I hit this warning: WARNING: CPU: 0 PID: 13 at kernel/rcu/srcutree.c:236 check_init_srcu_struct+0xe/0x61 Modules linked in: CPU: 0 PID: 13 Comm: watchdog/0 Not tainted 4.18.0-rc6-test+ #6 Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014 RIP: 0010:check_init_srcu_struct+0xe/0x61 Code: 48 c7 c6 ec 8a 65 b4 e8 ff 79 fe ff 48 89 df 31 f6 e8 f2 fa ff ff 5a 5b 41 5c 5d c3 0f 1f 44 00 00 83 3d 68 94 b8 01 01 75 02 <0f> 0b 48 8b 87 f0 0a 00 00 a8 03 74 45 55 48 89 e5 41 55 41 54 4c RSP: 0000:ffff96eb9ea03e68 EFLAGS: 00010246 RAX: ffff96eb962b5b01 RBX: ffffffffb4a87420 RCX: 0000000000000001 RDX: ffffffffb3107969 RSI: ffff96eb962b5b40 RDI: ffffffffb4a87420 RBP: ffff96eb9ea03eb0 R08: ffffabbd00cd7f48 R09: 0000000000000000 R10: ffff96eb9ea03e68 R11: ffffffffb4a6eec0 R12: ffff96eb962b5b40 R13: ffff96eb9ea03ef8 R14: ffffffffb3107969 R15: ffffffffb3107948 FS: 0000000000000000(0000) GS:ffff96eb9ea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff96eb13ab2000 CR3: 0000000192a1e001 CR4: 00000000001606f0 Call Trace: ? __call_srcu+0x2d/0x290 ? rcu_process_callbacks+0x26e/0x448 ? allocate_probes+0x2b/0x2b call_srcu+0x13/0x15 rcu_free_old_probes+0x1f/0x21 rcu_process_callbacks+0x2ed/0x448 __do_softirq+0x172/0x336 irq_exit+0x62/0xb2 smp_apic_timer_interrupt+0x161/0x19e apic_timer_interrupt+0xf/0x20 The problem is that the enabling of trace events before RCU is set up will cause SRCU to give this warning. To avoid this, add a list to store probes that need to be freed till after RCU is initialized, and then free them then. Link: http://lkml.kernel.org/r/20180810113554.1df28050@gandalf.local.home Link: http://lkml.kernel.org/r/20180810123517.5e9714ad@gandalf.local.home Acked-by: Paul E. McKenney Reviewed-by: Joel Fernandes (Google) Fixes: e6753f23d961d ("tracepoint: Make rcuidle tracepoint callers use SRCU") Signed-off-by: Steven Rostedt (VMware)

tracepoint: Make rcuidle tracepoint callers use SRCU

2018-07-30T23:13:03Z

In recent tests with IRQ on/off tracepoints, a large performance overhead ~10% is noticed when running hackbench. This is root caused to calls to rcu_irq_enter_irqson and rcu_irq_exit_irqson from the tracepoint code. Following a long discussion on the list [1] about this, we concluded that srcu is a better alternative for use during rcu idle. Although it does involve extra barriers, its lighter than the sched-rcu version which has to do additional RCU calls to notify RCU idle about entry into RCU sections. In this patch, we change the underlying implementation of the trace_*_rcuidle API to use SRCU. This has shown to improve performance alot for the high frequency irq enable/disable tracepoints. Test: Tested idle and preempt/irq tracepoints. Here are some performance numbers: With a run of the following 30 times on a single core x86 Qemu instance with 1GB memory: hackbench -g 4 -f 2 -l 3000 Completion times in seconds. CONFIG_PROVE_LOCKING=y. No patches (without this series) Mean: 3.048 Median: 3.025 Std Dev: 0.064 With Lockdep using irq tracepoints with RCU implementation: Mean: 3.451 (-11.66 %) Median: 3.447 (-12.22%) Std Dev: 0.049 With Lockdep using irq tracepoints with SRCU implementation (this series): Mean: 3.020 (I would consider the improvement against the "without this series" case as just noise). Median: 3.013 Std Dev: 0.033 [1] https://patchwork.kernel.org/patch/10344297/ [remove rcu_read_lock_sched_notrace as its the equivalent of preempt_disable_notrace and is unnecessary to call in tracepoint code] Link: http://lkml.kernel.org/r/20180730222423.196630-3-joel@joelfernandes.org Cleaned-up-by: Peter Zijlstra Acked-by: Peter Zijlstra Reviewed-by: Mathieu Desnoyers Signed-off-by: Joel Fernandes (Google) [ Simplified WARN_ON_ONCE() ] Signed-off-by: Steven Rostedt (VMware)

tracepoints: Fix the descriptions of tracepoint_probe_register{_prio}

2018-05-28T16:49:51Z

The description of tracepoint_probe_register duplicates with tracepoint_probe_register_prio. This patch cleans up the descriptions. Link: http://lkml.kernel.org/r/20170616082643.7311-1-jlee@suse.com Signed-off-by: "Lee, Chun-Yi" Signed-off-by: Steven Rostedt (VMware)

tracepoint: Do not warn on ENOMEM

2018-04-30T16:09:56Z

Tracepoint should only warn when a kernel API user does not respect the required preconditions (e.g. same tracepoint enabled twice, or called to remove a tracepoint that does not exist). Silence warning in out-of-memory conditions, given that the error is returned to the caller. This ensures that out-of-memory error-injection testing does not trigger warnings in tracepoint.c, which were seen by syzbot. Link: https://lkml.kernel.org/r/001a114465e241a8720567419a72@google.com Link: https://lkml.kernel.org/r/001a1140e0de15fc910567464190@google.com Link: http://lkml.kernel.org/r/20180315124424.32319-1-mathieu.desnoyers@efficios.com CC: Peter Zijlstra CC: Jiri Olsa CC: Arnaldo Carvalho de Melo CC: Alexander Shishkin CC: Namhyung Kim CC: stable@vger.kernel.org Fixes: de7b2973903c6 ("tracepoint: Use struct pointer instead of name hash for reg/unreg tracepoints") Reported-by: syzbot+9c0d616860575a73166a@syzkaller.appspotmail.com Reported-by: syzbot+4e9ae7fa46233396f64d@syzkaller.appspotmail.com Signed-off-by: Mathieu Desnoyers Signed-off-by: Steven Rostedt (VMware)