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authorThomas Zimmermann <tzimmermann@suse.de>2021-12-17 11:33:33 +0100
committerThomas Zimmermann <tzimmermann@suse.de>2021-12-17 11:33:33 +0100
commit1758047057dbe329be712a31b79db7151b5871f8 (patch)
tree00203eb55328f2feda70b3d37c964287b364796f /kernel/livepatch/patch.c
parentdrm/locking: fix __stack_depot_* name conflict (diff)
parentMerge tag 'mediatek-drm-next-5.17' of https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux into drm-next (diff)
downloadlinux-rng-1758047057dbe329be712a31b79db7151b5871f8.tar.xz
linux-rng-1758047057dbe329be712a31b79db7151b5871f8.zip
Merge drm/drm-next into drm-misc-next-fixes
Backmerging to bring drm-misc-next-fixes up to the latest state for the current release cycle. Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Diffstat (limited to 'kernel/livepatch/patch.c')
-rw-r--r--kernel/livepatch/patch.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c
index e8029aea67f1..fe316c021d73 100644
--- a/kernel/livepatch/patch.c
+++ b/kernel/livepatch/patch.c
@@ -49,14 +49,15 @@ static void notrace klp_ftrace_handler(unsigned long ip,
ops = container_of(fops, struct klp_ops, fops);
+ /*
+ * The ftrace_test_recursion_trylock() will disable preemption,
+ * which is required for the variant of synchronize_rcu() that is
+ * used to allow patching functions where RCU is not watching.
+ * See klp_synchronize_transition() for more details.
+ */
bit = ftrace_test_recursion_trylock(ip, parent_ip);
if (WARN_ON_ONCE(bit < 0))
return;
- /*
- * A variant of synchronize_rcu() is used to allow patching functions
- * where RCU is not watching, see klp_synchronize_transition().
- */
- preempt_disable_notrace();
func = list_first_or_null_rcu(&ops->func_stack, struct klp_func,
stack_node);
@@ -120,7 +121,6 @@ static void notrace klp_ftrace_handler(unsigned long ip,
klp_arch_set_pc(fregs, (unsigned long)func->new_func);
unlock:
- preempt_enable_notrace();
ftrace_test_recursion_unlock(bit);
}