The following commit has been merged into the perf/kprobes branch of tip:
Commit-ID: bcb53209be5cb32d485507452edda19b78f31d84
Gitweb:
https://git.kernel.org/tip/bcb53209be5cb32d485507452edda19b78f31d84
Author: Masami Hiramatsu <[email protected]>
AuthorDate: Tue, 01 Sep 2020 00:12:07 +09:00
Committer: Ingo Molnar <[email protected]>
CommitterDate: Mon, 14 Sep 2020 11:20:03 +02:00
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 <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Cc: [email protected]
Link:
https://lore.kernel.org/r/159888672694.1411785.5987998076694782591.stgit@devnote2
---
kernel/kprobes.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 732a701..3b61ae8 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);
}
