Hi Muchun, On Thu, 20 Aug 2020 11:19:33 +0800 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. > Good catch! Hmm, I think we also need an assertion in kill_kprobe() so that p is already gone. Anyway, this looks good to me. Acked-by: Masami Hiramatsu <[email protected]> Thanks! > Fixes: 0cb2f1372baa ("kprobes: Fix NULL pointer dereference at > kprobe_ftrace_handler") > Signed-off-by: Muchun Song <[email protected]> > Co-developed-by: Chengming Zhou <[email protected]> > Signed-off-by: Chengming Zhou <[email protected]> > --- > kernel/kprobes.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index d36e2b017588..7bac3ea44ff4 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -2422,7 +2422,10 @@ 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 +2442,7 @@ 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 > -- Masami Hiramatsu <[email protected]>
