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authorMasami Hiramatsu <mhiramat@kernel.org>2020-09-01 00:12:07 +0900
committerIngo Molnar <mingo@kernel.org>2020-09-14 11:20:03 +0200
commitbcb53209be5cb32d485507452edda19b78f31d84 (patch)
treecd0a53bcb9b0672442e3436bc6c14f3835e3503d
parent319f0ce284fff8e4f95167cb144acc905d0584c7 (diff)
downloadlinux-bcb53209be5cb32d485507452edda19b78f31d84.tar.bz2
kprobes: Fix to check probe enabled before disarm_kprobe_ftrace()
Commit: 0cb2f1372baa ("kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler") fixed one bug but the underlying bugs are not completely fixed yet. If we run a kprobe_module.tc of ftracetest, a warning triggers: # ./ftracetest test.d/kprobe/kprobe_module.tc === Ftrace unit tests === [1] Kprobe dynamic event - probing module ... ------------[ cut here ]------------ Failed to disarm kprobe-ftrace at trace_printk_irq_work+0x0/0x7e [trace_printk] (-2) WARNING: CPU: 7 PID: 200 at kernel/kprobes.c:1091 __disarm_kprobe_ftrace.isra.0+0x7e/0xa0 This is because the kill_kprobe() calls disarm_kprobe_ftrace() even if the given probe is not enabled. In that case, ftrace_set_filter_ip() fails because the given probe point is not registered to ftrace. Fix to check the given (going) probe is enabled before invoking disarm_kprobe_ftrace(). Fixes: 0cb2f1372baa ("kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler") Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/159888672694.1411785.5987998076694782591.stgit@devnote2
-rw-r--r--kernel/kprobes.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 732a70163584..3b61ae8ff5da 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2235,9 +2235,10 @@ static void kill_kprobe(struct kprobe *p)
/*
* The module is going away. We should disarm the kprobe which
- * is using ftrace.
+ * is using ftrace, because ftrace framework is still available at
+ * MODULE_STATE_GOING notification.
*/
- if (kprobe_ftrace(p))
+ if (kprobe_ftrace(p) && !kprobe_disabled(p) && !kprobes_all_disarmed)
disarm_kprobe_ftrace(p);
}