FAILED: patch "[PATCH] tracing/osnoise: Call synchronize_rcu() when unregistering" failed to apply to 6.1-stable tree

FAILED: patch "[PATCH] tracing/osnoise: Call synchronize_rcu() when unregistering" failed to apply to 6.1-stable tree

[gregkh]

The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x fe58f457ad8d0a2bef4e053cfecca4b5cd266b1a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026072147-clang-iguana-51e4@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From fe58f457ad8d0a2bef4e053cfecca4b5cd266b1a Mon Sep 17 00:00:00 2001
From: Crystal Wood <crwood@redhat.com>
Date: Mon, 8 Jun 2026 23:54:30 -0500
Subject: [PATCH] tracing/osnoise: Call synchronize_rcu() when unregistering

This ensures that any RCU readers traversing the instance list
have finished, before releasing the reference on the tracer that
the instance points to.

Cc: stable@vger.kernel.org
Fixes: a6ed2aee54644 ("tracing: Switch to kvfree_rcu() API")
Link: https://patch.msgid.link/20260609045430.1589786-1-crwood@redhat.com
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Crystal Wood <crwood@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index 5e83c4f6f2b4..0e1265acd1cc 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -179,7 +179,9 @@ static void osnoise_unregister_instance(struct trace_array *tr)
 	if (!found)
 		return;
 
-	kvfree_rcu_mightsleep(inst);
+	/* Do a full sync to ensure that tr remains valid, not just inst */
+	synchronize_rcu();
+	kvfree(inst);
 }
 
 /*

[PATCH 6.1.y 1/2] tracing: Rename kvfree_rcu() to kvfree_rcu_mightsleep()

[Sasha Levin]

From: "Uladzislau Rezki (Sony)" <urezki@gmail.com>

[ Upstream commit cae16f2c2e11c60c888715f4d98c12740683d6a2 ]

The kvfree_rcu() macro's single-argument form is deprecated.  Therefore
switch to the new kvfree_rcu_mightsleep() variant. The goal is to
avoid accidental use of the single-argument forms, which can introduce
functionality bugs in atomic contexts and latency bugs in non-atomic
contexts.

Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Stable-dep-of: fe58f457ad8d ("tracing/osnoise: Call synchronize_rcu() when unregistering")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/trace/trace_osnoise.c | 2 +-
 kernel/trace/trace_probe.c   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index 676d9a3e65cde6..417b62f7550978 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -137,7 +137,7 @@ static void osnoise_unregister_instance(struct trace_array *tr)
 	if (!found)
 		return;
 
-	kvfree_rcu(inst);
+	kvfree_rcu_mightsleep(inst);
 }
 
 /*
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 125111d310d1ba..241b7ba9a3a777 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -1179,7 +1179,7 @@ int trace_probe_remove_file(struct trace_probe *tp,
 		return -ENOENT;
 
 	list_del_rcu(&link->list);
-	kvfree_rcu(link);
+	kvfree_rcu_mightsleep(link);
 
 	if (list_empty(&tp->event->files))
 		trace_probe_clear_flag(tp, TP_FLAG_TRACE);
-- 
2.53.0

[PATCH 6.1.y 2/2] tracing/osnoise: Call synchronize_rcu() when unregistering

[Sasha Levin]

From: Crystal Wood <crwood@redhat.com>

[ Upstream commit fe58f457ad8d0a2bef4e053cfecca4b5cd266b1a ]

This ensures that any RCU readers traversing the instance list
have finished, before releasing the reference on the tracer that
the instance points to.

Cc: stable@vger.kernel.org
Fixes: a6ed2aee54644 ("tracing: Switch to kvfree_rcu() API")
Link: https://patch.msgid.link/20260609045430.1589786-1-crwood@redhat.com
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Crystal Wood <crwood@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/trace/trace_osnoise.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index 417b62f7550978..3b3f31ca45831b 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -137,7 +137,9 @@ static void osnoise_unregister_instance(struct trace_array *tr)
 	if (!found)
 		return;
 
-	kvfree_rcu_mightsleep(inst);
+	/* Do a full sync to ensure that tr remains valid, not just inst */
+	synchronize_rcu();
+	kvfree(inst);
 }
 
 /*
-- 
2.53.0