This is a note to let you know that I've just added the patch titled
tracepoint: static call: Compare data on transition from 2->1 callees
to the 5.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tracepoint-static-call-compare-data-on-transition-from-2-1-callees.patch
and it can be found in the queue-5.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From f7ec4121256393e1d03274acdca73eb18958f27e Mon Sep 17 00:00:00 2001
From: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Date: Thu, 5 Aug 2021 09:27:15 -0400
Subject: tracepoint: static call: Compare data on transition from 2->1 callees
From: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
commit f7ec4121256393e1d03274acdca73eb18958f27e upstream.
On transition from 2->1 callees, we should be comparing .data rather
than .func, because the same callback can be registered twice with
different data, and what we care about here is that the data of array
element 0 is unchanged to skip rcu sync.
Link: https://lkml.kernel.org/r/20210805132717.23813-2-mathieu.desnoyers@xxxxxxxxxxxx
Link: https://lore.kernel.org/io-uring/4ebea8f0-58c9-e571-fd30-0ce4f6f09c70@xxxxxxxxx/
Cc: stable@xxxxxxxxxxxxxxx
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
Cc: Stefan Metzmacher <metze@xxxxxxxxx>
Fixes: 547305a64632 ("tracepoint: Fix out of sync data passing by static caller")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/tracepoint.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -338,7 +338,7 @@ static int tracepoint_remove_func(struct
} else {
rcu_assign_pointer(tp->funcs, tp_funcs);
tracepoint_update_call(tp, tp_funcs,
- tp_funcs[0].func != old[0].func);
+ tp_funcs[0].data != old[0].data);
}
release_probes(old);
return 0;
Patches currently in stable-queue which might be from mathieu.desnoyers@xxxxxxxxxxxx are
queue-5.13/tracepoint-static-call-compare-data-on-transition-from-2-1-callees.patch
queue-5.13/tracepoint-use-rcu-get-state-and-cond-sync-for-static-call-updates.patch
queue-5.13/tracepoint-fix-static-call-function-vs-data-state-mismatch.patch
