[PATCH] ring-buffer: Do not record in NMI if the arch does not support cmpxchg in NMI
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LANDED
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2023-12-13 22:53:23
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lkml
Subsystem:
the rest, tracing · Maintainers:
Linus Torvalds, Steven Rostedt, Masami Hiramatsu
Landed in mainline as 712292308af2 on 2023-12-15.
From: "Steven Rostedt (Google)" <rostedt@goodmis.org> As the ring buffer recording requires cmpxchg() to work, if the architecture does not support cmpxchg in NMI, then do not do any recording within an NMI. Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> --- kernel/trace/ring_buffer.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 8f8887f025c9..caaffcdc6350 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c@@ -3719,6 +3719,12 @@ rb_reserve_next_event(struct trace_buffer *buffer, int nr_loops = 0; int add_ts_default; + /* ring buffer does cmpxchg, make sure it is safe in NMI context */ + if (!IS_ENABLED(CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG) && + (unlikely(in_nmi()))) { + return NULL; + } + rb_start_commit(cpu_buffer); /* The commit page can not change after this */
--
2.42.0