Commit 5f843ed4 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Ingo Molnar
Browse files

kprobes: Fix error check when reusing optimized probes

The following commit introduced a bug in one of our error paths:

  819319fc ("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 thi...
parent 618d919c
Showing with 2 additions and 4 deletions
+2 -4
......@@ -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;
......
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