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* [PATCH v4 00/27] tracing vs world
@ 2020-02-21 13:34 Peter Zijlstra
  2020-02-21 13:34 ` [PATCH v4 01/27] lockdep: Teach lockdep about "USED" <- "IN-NMI" inversions Peter Zijlstra
                   ` (26 more replies)
  0 siblings, 27 replies; 85+ messages in thread
From: Peter Zijlstra @ 2020-02-21 13:34 UTC (permalink / raw)
  To: linux-kernel, linux-arch, rostedt
  Cc: peterz, mingo, joel, gregkh, gustavo, tglx, paulmck, josh,
	mathieu.desnoyers, jiangshanlai, luto, tony.luck, frederic,
	dan.carpenter, mhiramat

Hi all,


These here patches are the result of Mathieu and Steve trying to get commit
865e63b04e9b2 ("tracing: Add back in rcu_irq_enter/exit_irqson() for rcuidle
tracepoints") reverted again.

One of the things discovered is that tracing MUST NOT happen before nmi_enter()
or after nmi_exit(). Audit results of the previous version are still valid.

This then snowballed into auditing other exceptions, notably #MC, and #BP. Lots
of patches came out of that.

I would love for some tooling in this area. Dan, smatch has full callchains
right? Would it be possible to have an __assert_no_tracing__() marker of sorts
that validates that no possible callchain reaching that assertion has hit
tracing before that point?

It would mean you have to handle the various means of 'notrace' annotation
(both the function attribute as well as the Makefile rules), recognising
tracepoints and ideally handling NOKPROBE annotations.

NOTE:
  patches 19,20,21 already live in tip/locking/kcsan and are included
  here because 20,21 are needed for the patches following to make sense.
  If/when this gets merged, we need to figure out how to resolve this.

Changes since -v3:

 - Replaced the #DF patch with one from Boris
 - Moved trace_rcu_{enter,exit}() into rcupdate.h
 - Flipped TIF_SIGPENDING and TIF_NOTIFY_RESUME handling
 - Added comment to nmi_enter()
 - fixed various compile fails
 - inlined bsearch()
 - Added lockdep checking for USED <- IN-NMI recursion
 - Added rcu_nmi_enter vs kprobes comment

Changes since -v2:

 - #MC / ist_enter() audit -- first 4 patches. After this in_nmi() should
   always be set 'correctly'.
 - RCU IRQ enter/exit function simplification
 - #BP / poke_int3_handler() audit -- last many patches.
 - pulled in some locking/kcsan patches

Changes since -v1:

 - Added tags
 - Changed #4; changed nmi_enter() to use __preempt_count_add() vs
   marking preempt_count_add() notrace.
 - Changed #5; confusion on which functions are notrace due to Makefile
 - Added #9; remove limitation on the perf-function-trace coupling


^ permalink raw reply	[flat|nested] 85+ messages in thread

end of thread, other threads:[~2020-03-20 12:58 UTC | newest]

Thread overview: 85+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-02-21 13:34 [PATCH v4 00/27] tracing vs world Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 01/27] lockdep: Teach lockdep about "USED" <- "IN-NMI" inversions Peter Zijlstra
2020-02-21 15:08   ` Steven Rostedt
2020-02-21 20:25     ` Peter Zijlstra
2020-02-21 20:28       ` Steven Rostedt
2020-02-21 22:01       ` Frederic Weisbecker
2020-02-22  3:08   ` Joel Fernandes
2020-02-24 10:10     ` Peter Zijlstra
2020-02-25  2:12       ` Joel Fernandes
2020-03-20 12:58   ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 02/27] hardirq/nmi: Allow nested nmi_enter() Peter Zijlstra
2020-02-21 22:21   ` Frederic Weisbecker
2020-02-24 12:13     ` Petr Mladek
2020-02-25  1:30       ` Frederic Weisbecker
2020-02-24 16:13     ` Peter Zijlstra
2020-02-25  3:09       ` Frederic Weisbecker
2020-02-25 15:41         ` Peter Zijlstra
2020-02-25 16:21           ` Frederic Weisbecker
2020-02-25 22:10           ` Frederic Weisbecker
2020-02-27  9:10             ` Peter Zijlstra
2020-02-27 13:34               ` Frederic Weisbecker
2020-02-21 13:34 ` [PATCH v4 03/27] x86/entry: Flip _TIF_SIGPENDING and _TIF_NOTIFY_RESUME handling Peter Zijlstra
2020-02-21 16:14   ` Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 04/27] x86/mce: Delete ist_begin_non_atomic() Peter Zijlstra
2020-02-21 19:07   ` Andy Lutomirski
2020-02-21 23:40   ` Frederic Weisbecker
2020-02-21 13:34 ` [PATCH v4 05/27] x86: Replace ist_enter() with nmi_enter() Peter Zijlstra
2020-02-21 19:05   ` Andy Lutomirski
2020-02-21 20:22     ` Peter Zijlstra
2020-02-24 10:43       ` Peter Zijlstra
2020-02-24 16:27         ` Steven Rostedt
2020-02-24 16:34           ` Peter Zijlstra
2020-02-24 16:47             ` Steven Rostedt
2020-02-24 21:31               ` Peter Zijlstra
2020-02-24 22:02                 ` Steven Rostedt
2020-02-26 10:25                   ` Peter Zijlstra
2020-02-26 13:16                     ` Peter Zijlstra
2020-02-26 10:27                   ` Peter Zijlstra
2020-02-26 15:20                     ` Steven Rostedt
2020-03-07  1:53                     ` Masami Hiramatsu
2020-02-21 13:34 ` [PATCH v4 06/27] x86/doublefault: Remove memmove() call Peter Zijlstra
2020-02-21 19:10   ` Andy Lutomirski
2020-02-21 13:34 ` [PATCH v4 07/27] rcu: Make RCU IRQ enter/exit functions rely on in_nmi() Peter Zijlstra
2020-02-26  0:23   ` Frederic Weisbecker
2020-02-21 13:34 ` [PATCH v4 08/27] rcu/kprobes: Comment why rcu_nmi_enter() is marked NOKPROBE Peter Zijlstra
2020-02-26  0:27   ` Frederic Weisbecker
2020-02-21 13:34 ` [PATCH v4 09/27] rcu: Rename rcu_irq_{enter,exit}_irqson() Peter Zijlstra
2020-02-21 20:21   ` Steven Rostedt
2020-02-24 10:24     ` Peter Zijlstra
2020-02-26  0:35   ` Frederic Weisbecker
2020-02-21 13:34 ` [PATCH v4 10/27] rcu: Mark rcu_dynticks_curr_cpu_in_eqs() inline Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 11/27] rcu,tracing: Create trace_rcu_{enter,exit}() Peter Zijlstra
2020-03-06 11:50   ` Peter Zijlstra
2020-03-06 12:40     ` Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 12/27] sched,rcu,tracing: Avoid tracing before in_nmi() is correct Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 13/27] x86,tracing: Add comments to do_nmi() Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 14/27] perf,tracing: Prepare the perf-trace interface for RCU changes Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 15/27] tracing: Employ trace_rcu_{enter,exit}() Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 16/27] tracing: Remove regular RCU context for _rcuidle tracepoints (again) Peter Zijlstra
2020-03-06 10:43   ` Peter Zijlstra
2020-03-06 11:31     ` Peter Zijlstra
2020-03-06 15:51       ` Alexei Starovoitov
2020-03-06 16:04         ` Mathieu Desnoyers
2020-03-06 17:55           ` Steven Rostedt
2020-03-06 18:45             ` Joel Fernandes
2020-03-06 18:59               ` Steven Rostedt
2020-03-06 19:14                 ` Joel Fernandes
2020-03-06 20:22             ` Mathieu Desnoyers
2020-03-06 20:45               ` Steven Rostedt
2020-03-06 20:55                 ` Mathieu Desnoyers
2020-03-06 21:06                   ` Steven Rostedt
2020-03-06 23:10                   ` Alexei Starovoitov
2020-03-06 17:21         ` Joel Fernandes
2020-02-21 13:34 ` [PATCH v4 17/27] perf,tracing: Allow function tracing when !RCU Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 18/27] x86/int3: Ensure that poke_int3_handler() is not traced Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 19/27] locking/atomics, kcsan: Add KCSAN instrumentation Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 20/27] asm-generic/atomic: Use __always_inline for pure wrappers Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 21/27] asm-generic/atomic: Use __always_inline for fallback wrappers Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 22/27] compiler: Simple READ/WRITE_ONCE() implementations Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 23/27] locking/atomics: Flip fallbacks and instrumentation Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 24/27] x86/int3: Avoid atomic instrumentation Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 25/27] lib/bsearch: Provide __always_inline variant Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 26/27] x86/int3: Inline bsearch() Peter Zijlstra
2020-02-21 13:34 ` [PATCH v4 27/27] x86/int3: Ensure that poke_int3_handler() is not sanitized Peter Zijlstra
2020-02-23 19:36   ` kbuild test robot

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