| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.8 104/118] kprobes: fix kill kprobe which has been marked as gone | Date | Mon, 21 Sep 2020 18:28:36 +0200 |
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From: Muchun Song <songmuchun@bytedance.com>
commit b0399092ccebd9feef68d4ceb8d6219a8c0caa05 upstream.
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") Co-developed-by: Chengming Zhou <zhouchengming@bytedance.com> Signed-off-by: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: "Naveen N . Rao" <naveen.n.rao@linux.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Song Liu <songliubraving@fb.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20200822030055.32383-1-songmuchun@bytedance.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- kernel/kprobes.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
--- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2108,6 +2108,9 @@ 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)) { /* @@ -2365,7 +2368,10 @@ static int kprobes_module_callback(struc 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))) { @@ -2382,6 +2388,7 @@ static int kprobes_module_callback(struc */ kill_kprobe(p); } + } } if (val == MODULE_STATE_GOING) remove_module_kprobe_blacklist(mod);
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