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tracing: Disable interrupt or preemption before acquiring arch_spinlock_t

Waiman Long requested to merge llong1/centos-stream-9:bz2128231_trace into main

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2128231

commit c0a581d7126c0bbc96163276f585fd7b4e4d8d0e
Author: Waiman Long longman@redhat.com
Date: Thu, 22 Sep 2022 10:56:22 -0400

tracing: Disable interrupt or preemption before acquiring arch_spinlock_t

It was found that some tracing functions in kernel/trace/trace.c acquire
an arch_spinlock_t with preemption and irqs enabled. An example is the
tracing_saved_cmdlines_size_read() function which intermittently causes
a "BUG: using smp_processor_id() in preemptible" warning when the LTP
read_all_proc test is run.

That can be problematic in case preemption happens after acquiring the
lock. Add the necessary preemption or interrupt disabling code in the
appropriate places before acquiring an arch_spinlock_t.

The convention here is to disable preemption for trace_cmdline_lock and
interupt for max_lock.

Link: https://lkml.kernel.org/r/20220922145622.1744826-1-longman@redhat.com

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: stable@vger.kernel.org
Fixes: a35873a0993b ("tracing: Add conditional snapshot")
Fixes: 939c7a4f04fc ("tracing: Introduce saved_cmdlines_size file")
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Signed-off-by: Waiman Long longman@redhat.com

Edited by Waiman Long

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