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Commit 82b0f70f authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Greg Kroah-Hartman
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kprobes: Return error if we fail to reuse kprobe instead of BUG_ON() 



[ 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: default avatarMasami 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@devbox


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 313c940d

kernel/kprobes.c

+20 −7
Original line number Diff line number Diff line
@@ -700,9 +700,10 @@ static void unoptimize_kprobe(struct kprobe *p, bool force) 
}



/* 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));

	/*
@@ -714,8 +715,12 @@ static void reuse_unused_kprobe(struct kprobe *ap) 
	/* 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 */
@@ -940,11 +945,16 @@ static void __disarm_kprobe(struct kprobe *p, bool reopt) 
#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)
@@ -1318,9 +1328,12 @@ static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p) 
			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)) {

		/*