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authorMasami Hiramatsu <mhiramat@kernel.org>2019-04-15 15:01:25 +0900
committerIngo Molnar <mingo@kernel.org>2019-04-16 09:38:16 +0200
commit5f843ed415581cfad4ef8fefe31c138a8346ca8a (patch)
tree88c8269be0deb7d9c01ae1cb7d52694075ddf383 /kernel
parent618d919cae2fcaadc752f27ddac8b939da8b441a (diff)
downloadlinux-5f843ed415581cfad4ef8fefe31c138a8346ca8a.tar.bz2
kprobes: Fix error check when reusing optimized probes
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 <mhiramat@kernel.org> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S . Miller <davem@davemloft.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Naveen N . Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@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 <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kprobes.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index c83e54727131..b1ea30a5540e 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -709,7 +709,6 @@ static void unoptimize_kprobe(struct kprobe *p, bool force)
static int reuse_unused_kprobe(struct kprobe *ap)
{
struct optimized_kprobe *op;
- int ret;
/*
* Unused kprobe MUST be on the way of delayed unoptimizing (means
@@ -720,9 +719,8 @@ static int reuse_unused_kprobe(struct kprobe *ap)
/* 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;