| Message ID | 20250120235721.407068250@goodmis.org (mailing list archive) |
|---|---|
| State | Queued |
| Commit | 274c08f3b8b8d24bc1aba3be39fd0586231e84c9 |
| Headers | show |
| Series | lib/atomic64: ring-buffer: Fix infinite recursion on some 32bit archs | expand |
On Mon, 20 Jan 2025 18:56:56 -0500 Steven Rostedt <rostedt@goodmis.org> wrote: > From: Steven Rostedt <rostedt@goodmis.org> > > Some architectures can not safely do atomic64 operations in NMI context. > Since the ring buffer relies on atomic64 operations to do its time > keeping, if an event is requested in NMI context, reject it for these > architectures. > Looks good to me. Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> > Cc: stable@vger.kernel.org > Fixes: c84897c0ff592 ("ring-buffer: Remove 32bit timestamp logic") > Closes: https://lore.kernel.org/all/86fb4f86-a0e4-45a2-a2df-3154acc4f086@gaisler.com/ > Reported-by: Ludwig Rydberg <ludwig.rydberg@gaisler.com> > Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> > --- > kernel/trace/ring_buffer.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c > index 6d61ff78926b..b8e0ae15ca5b 100644 > --- a/kernel/trace/ring_buffer.c > +++ b/kernel/trace/ring_buffer.c > @@ -4398,8 +4398,13 @@ 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) && > + /* > + * ring buffer does cmpxchg as well as atomic64 operations > + * (which some archs use locking for atomic64), make sure this > + * is safe in NMI context > + */ > + if ((!IS_ENABLED(CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG) || > + IS_ENABLED(CONFIG_GENERIC_ATOMIC64)) && > (unlikely(in_nmi()))) { > return NULL; > } > -- > 2.45.2 > >
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 6d61ff78926b..b8e0ae15ca5b 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -4398,8 +4398,13 @@ 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) && + /* + * ring buffer does cmpxchg as well as atomic64 operations + * (which some archs use locking for atomic64), make sure this + * is safe in NMI context + */ + if ((!IS_ENABLED(CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG) || + IS_ENABLED(CONFIG_GENERIC_ATOMIC64)) && (unlikely(in_nmi()))) { return NULL; }