4.4-stable review patch. If anyone has any objections, please let me know.
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From: Masami Hiramatsu mhiramat@kernel.org
[ Upstream commit 819319fc93461c07b9cdb3064f154bd8cfd48172 ]
Make reuse_unused_kprobe() to return error code if it fails to reuse unused kprobe for optprobe instead of calling BUG_ON().
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 Link: http://lkml.kernel.org/r/153666124040.21306.14150398706331307654.stgit@devbo... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/kprobes.c | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-)
--- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -665,9 +665,10 @@ static void unoptimize_kprobe(struct kpr }
/* Cancel unoptimizing for reusing */ -static void reuse_unused_kprobe(struct kprobe *ap) +static int reuse_unused_kprobe(struct kprobe *ap) { struct optimized_kprobe *op; + int ret;
BUG_ON(!kprobe_unused(ap)); /* @@ -681,8 +682,12 @@ static void reuse_unused_kprobe(struct k /* Enable the probe again */ ap->flags &= ~KPROBE_FLAG_DISABLED; /* Optimize it again (remove from op->list) */ - BUG_ON(!kprobe_optready(ap)); + ret = kprobe_optready(ap); + if (ret) + return ret; + optimize_kprobe(ap); + return 0; }
/* Remove optimized instructions */ @@ -894,11 +899,16 @@ static void __disarm_kprobe(struct kprob #define kprobe_disarmed(p) kprobe_disabled(p) #define wait_for_kprobe_optimizer() do {} while (0)
-/* There should be no unused kprobes can be reused without optimization */ -static void reuse_unused_kprobe(struct kprobe *ap) +static int reuse_unused_kprobe(struct kprobe *ap) { + /* + * If the optimized kprobe is NOT supported, the aggr kprobe is + * released at the same time that the last aggregated kprobe is + * unregistered. + * Thus there should be no chance to reuse unused kprobe. + */ printk(KERN_ERR "Error: There should be no unused kprobe here.\n"); - BUG_ON(kprobe_unused(ap)); + return -EINVAL; }
static void free_aggr_kprobe(struct kprobe *p) @@ -1276,9 +1286,12 @@ static int register_aggr_kprobe(struct k goto out; } init_aggr_kprobe(ap, orig_p); - } else if (kprobe_unused(ap)) + } else if (kprobe_unused(ap)) { /* This probe is going to die. Rescue it */ - reuse_unused_kprobe(ap); + ret = reuse_unused_kprobe(ap); + if (ret) + goto out; + }
if (kprobe_gone(ap)) { /*