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 <[email protected]> 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 <[email protected]> > Co-developed-by: Chengming Zhou <[email protected]> > Signed-off-by: Chengming Zhou <[email protected]> > Acked-by: Masami Hiramatsu <[email protected]> > --- > 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
