Hi Ingo,
Could you merge this fix to -tip?
I can resend it with other kprobes fixes.
Hi Muchun,
We also need;
Cc: sta...@vger.kernel.org
for bugfix so that the patch can be backported correctly after merged to
upstream.
Thank you,
On Mon, 31 Aug 2020 10:59:19 +0800
Muchun Song <songmuc...@bytedance.com> wrote:
> Cc Andrew and Steven.
>
> Any other comments or someone can add this to the queue for the
> merge window? It's worth fixing it.
>
> On Sat, Aug 22, 2020 at 11:01 AM Muchun Song <songmuc...@bytedance.com> wrote:
> >
> > If a kprobe is marked as gone, we should not kill it again. Otherwise,
> > we can disarm the kprobe more than once. In that case, the statistics
> > of kprobe_ftrace_enabled can unbalance which can lead to that kprobe
> > do not work.
> >
> > Fixes: e8386a0cb22f ("kprobes: support probing module __exit function")
> > Signed-off-by: Muchun Song <songmuc...@bytedance.com>
> > Co-developed-by: Chengming Zhou <zhouchengm...@bytedance.com>
> > Signed-off-by: Chengming Zhou <zhouchengm...@bytedance.com>
> > Acked-by: Masami Hiramatsu <mhira...@kernel.org>
> > ---
> > changelogs in v2:
> > 1. Add a WARN_ON_ONCE in the kill_kprobe() to catch incorrect use of it.
> > 2. Update 'Fixes' tag in the commmit log.
> >
> > kernel/kprobes.c | 9 ++++++++-
> > 1 file changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> > index d36e2b017588..9348b0c36ae0 100644
> > --- a/kernel/kprobes.c
> > +++ b/kernel/kprobes.c
> > @@ -2143,6 +2143,9 @@ static void kill_kprobe(struct kprobe *p)
> >
> > lockdep_assert_held(&kprobe_mutex);
> >
> > + if (WARN_ON_ONCE(kprobe_gone(p)))
> > + return;
> > +
> > p->flags |= KPROBE_FLAG_GONE;
> > if (kprobe_aggrprobe(p)) {
> > /*
> > @@ -2422,7 +2425,10 @@ static int kprobes_module_callback(struct
> > notifier_block *nb,
> > mutex_lock(&kprobe_mutex);
> > for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
> > head = &kprobe_table[i];
> > - hlist_for_each_entry(p, head, hlist)
> > + hlist_for_each_entry(p, head, hlist) {
> > + if (kprobe_gone(p))
> > + continue;
> > +
> > if (within_module_init((unsigned long)p->addr, mod)
> > ||
> > (checkcore &&
> > within_module_core((unsigned long)p->addr,
> > mod))) {
> > @@ -2439,6 +2445,7 @@ static int kprobes_module_callback(struct
> > notifier_block *nb,
> > */
> > kill_kprobe(p);
> > }
> > + }
> > }
> > if (val == MODULE_STATE_GOING)
> > remove_module_kprobe_blacklist(mod);
> > --
> > 2.11.0
> >
>
>
> --
> Yours,
> Muchun
--
Masami Hiramatsu <mhira...@kernel.org>
