From: Masami Hiramatsu <mhira...@kernel.org>
commit 5f843ed415581cfad4ef8fefe31c138a8346ca8a upstream.
The following commit introduced a bug in one of our error paths:
819319fc9346 ("kprobes: Return error if we fail to reuse kprobe instead of
BUG_ON()")
it missed to handle the return value of kprobe_optready() as
error-value. In reality, the kprobe_optready() returns a bool
result, so "true" case must be passed instead of 0.
This causes some errors on kprobe boot-time selftests on ARM:
[ ] Beginning kprobe tests...
[ ] Probe ARM code
[ ] kprobe
[ ] kretprobe
[ ] ARM instruction simulation
[ ] Check decoding tables
[ ] Run test cases
[ ] FAIL: test_case_handler not run
[ ] FAIL: Test andge r10, r11, r14, asr r7
[ ] FAIL: Scenario 11
...
[ ] FAIL: Scenario 7
[ ] Total instruction simulation tests=1631, pass=1433 fail=198
[ ] kprobe tests failed
This can happen if an optimized probe is unregistered and next
kprobe is registered on same address until the previous probe
is not reclaimed.
If this happens, a hidden aggregated probe may be kept in memory,
and no new kprobe can probe same address. Also, in that case
register_kprobe() will return "1" instead of minus error value,
which can mislead caller logic.
Signed-off-by: Masami Hiramatsu <mhira...@kernel.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamur...@intel.com>
Cc: David S . Miller <da...@davemloft.net>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Naveen N . Rao <naveen.n....@linux.vnet.ibm.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: sta...@vger.kernel.org # v5.0+
Fixes: 819319fc9346 ("kprobes: Return error if we fail to reuse kprobe instead
of BUG_ON()")
Link:
http://lkml.kernel.org/r/155530808559.32517.539898325433642204.stgit@devnote2
Signed-off-by: Ingo Molnar <mi...@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
kernel/kprobes.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -668,7 +668,6 @@ static void unoptimize_kprobe(struct kpr
static int reuse_unused_kprobe(struct kprobe *ap)
{
struct optimized_kprobe *op;
- int ret;
BUG_ON(!kprobe_unused(ap));
/*
@@ -682,9 +681,8 @@ static int reuse_unused_kprobe(struct kp
/* Enable the probe again */
ap->flags &= ~KPROBE_FLAG_DISABLED;
/* Optimize it again (remove from op->list) */
- ret = kprobe_optready(ap);
- if (ret)
- return ret;
+ if (!kprobe_optready(ap))
+ return -EINVAL;
optimize_kprobe(ap);
return 0;
