The following commit has been merged into the x86/entry branch of tip:
Commit-ID: a53a1d0435cdc2b66f41f75fa1cee31e8fe6d99e
Gitweb: https://git.kernel.org/tip/a53a1d0435cdc2b66f41f75fa1cee31e8fe6d99e
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Fri, 24 Jan 2020 22:08:45 +01:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Tue, 19 May 2020 16:04:05 +02:00
x86/int3: Avoid atomic instrumentation
Use arch_atomic_*() and __READ_ONCE() to ensure nothing untoward
creeps in and ruins things.
That is; this is the INT3 text poke handler, strictly limit the code
that runs in it, lest it inadvertenly hits yet another INT3.
Reported-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Reviewed-by: Alexandre Chartre <alexandre.chartre@xxxxxxxxxx>
Acked-by: Andy Lutomirski <luto@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20200505135313.517429268@xxxxxxxxxxxxx
---
arch/x86/kernel/alternative.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 1f4cb2c..686c8ac 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -960,9 +960,9 @@ static struct bp_patching_desc *bp_desc;
static __always_inline
struct bp_patching_desc *try_get_desc(struct bp_patching_desc **descp)
{
- struct bp_patching_desc *desc = READ_ONCE(*descp); /* rcu_dereference */
+ struct bp_patching_desc *desc = __READ_ONCE(*descp); /* rcu_dereference */
- if (!desc || !atomic_inc_not_zero(&desc->refs))
+ if (!desc || !arch_atomic_inc_not_zero(&desc->refs))
return NULL;
return desc;
@@ -971,7 +971,7 @@ struct bp_patching_desc *try_get_desc(struct bp_patching_desc **descp)
static __always_inline void put_desc(struct bp_patching_desc *desc)
{
smp_mb__before_atomic();
- atomic_dec(&desc->refs);
+ arch_atomic_dec(&desc->refs);
}
static __always_inline void *text_poke_addr(struct text_poke_loc *tp)
|