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FAILED: patch "[PATCH] kprobes: fix kill kprobe which has been marked as gone" failed to apply to 4.9-stable tree

PATCH [email protected] 1 participant 1 message Sep 21, 2020

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Stable branch kprobes
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The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b0399092ccebd9feef68d4ceb8d6219a8c0caa05 Mon Sep 17 00:00:00 2001
From: Muchun Song <[email protected]>
Date: Fri, 18 Sep 2020 21:20:21 -0700
Subject: [PATCH] kprobes: fix kill kprobe which has been marked as gone

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 <[email protected]>
Signed-off-by Muchun Song <[email protected]>
Signed-off-by Chengming Zhou <[email protected]>
Signed-off-by Andrew Morton <[email protected]>
Acked-by Masami Hiramatsu <[email protected]>
Cc "Naveen N . Rao" <[email protected]>
Cc Anil S Keshavamurthy <[email protected]>
Cc David S. Miller <[email protected]>
Cc Song Liu <[email protected]>
Cc Steven Rostedt <[email protected]>
Cc <[email protected]>
Link https://lkml.kernel.org/r/[email protected] open here
Signed-off-by Linus Torvalds <[email protected]>
kernel/kprobes.c +8 -1
index 287b263c9cb9..049da84e1952 100644
@@ -2140,6 +2140,9 @@ 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)) {
 		/*

@@ -2419,7 +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))) {

@@ -2436,6 +2442,7 @@ static int kprobes_module_callback(struct notifier_block *nb,
 				 */
 				kill_kprobe(p);
 			}
+		}
 	}
 	if (val == MODULE_STATE_GOING)
 		remove_module_kprobe_blacklist(mod);