On Tue, 05 May 2020 15:49:28 +0200 Thomas Gleixner <[email protected]> wrote:
> From: Peter Zijlstra <[email protected]> > > Use arch_atomic_*() and READ_ONCE_NOCHECK() 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 <[email protected]> > Signed-off-by: Peter Zijlstra (Intel) <[email protected]> > Signed-off-by: Thomas Gleixner <[email protected]> Looks good to me. Reviewed-by: Masami Hiramatsu <[email protected]> > --- > arch/x86/kernel/alternative.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > --- 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_NOCHECK(*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(st > 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) > -- Masami Hiramatsu <[email protected]>
