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| author | Peter Zijlstra <peterz@infradead.org> | 2020-01-24 22:08:45 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-06-11 15:14:53 +0200 |
| commit | ef882bfef933408360e4d9d0c2c83a1e2fc996f3 (patch) | |
| tree | d233031a2e6ab642f4d7a7c9ddf9d10f5388323d /arch/x86/kernel/alternative.c | |
| parent | x86/int3: Ensure that poke_int3_handler() is not traced (diff) | |
| download | linux-ef882bfef933408360e4d9d0c2c83a1e2fc996f3.tar.xz linux-ef882bfef933408360e4d9d0c2c83a1e2fc996f3.zip | |
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@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505135313.517429268@linutronix.de
Diffstat (limited to 'arch/x86/kernel/alternative.c')
| -rw-r--r-- | arch/x86/kernel/alternative.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index dd81ed5beeca..50a8d24a417e 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -1014,9 +1014,9 @@ 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; @@ -1025,7 +1025,7 @@ 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) |