Merge tag 'probes-fixes-v7.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probes fixes from Masami Hiramatsu:

 - fprobe: Use guard(rcu_sched_notrace) and check rcu_is_watching()

   Exit handlers early if !rcu_is_watching() to prevent potential
   use-after-free during unregistration in idle/quiescent states. Switch
   to guard(rcu_sched_notrace) to avoid fast-path lockdep overhead and
   recursion while ensuring safe grace period synchronization.

 - kprobes: Skip disarmed probes when checking optkprobe overlap

   Continue past disarmed or unprepared probes in get_optimized_kprobe()
   to find active optimized probes. This avoids overwriting active jump
   displacements which can lead to panic.

* tag 'probes-fixes-v7.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  kprobes: Skip disarmed probes when checking optkprobe overlap
  fprobe: Use guard(rcu_sched_notrace) and check rcu_is_watching()

1 files changed, 5 insertions, 3 deletions

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 4edd8ca5c657..e787e4948c8b 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -496,14 +496,16 @@ static bool kprobe_queued(struct kprobe *p)
 static struct kprobe *get_optimized_kprobe(kprobe_opcode_t *addr)
 {
 	int i;
-	struct kprobe *p = NULL;
+	struct kprobe *p;
 	struct optimized_kprobe *op;
 
 	/* Don't check i == 0, since that is a breakpoint case. */
-	for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH / sizeof(kprobe_opcode_t); i++)
+	for (i = 1; i < MAX_OPTIMIZED_LENGTH / sizeof(kprobe_opcode_t); i++) {
 		p = get_kprobe(addr - i);
+		/* A disabled probe can have prepared, but inactive, optinsns. */
+		if (!p || !kprobe_optready(p) || kprobe_disarmed(p))
+			continue;
 
-	if (p && kprobe_optready(p)) {
 		op = container_of(p, struct optimized_kprobe, kp);
 		if (arch_within_optimized_kprobe(op, addr))
 			return p;