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Commit 544adb41 authored by Jesper Juhl's avatar Jesper Juhl Committed by Linus Torvalds
Browse files

markers: don't risk NULL deref in marker 



get_marker() may return NULL, so test for it.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: default avatarJesper Juhl <jesper.juhl@gmail.com>
Acked-by: default avatarMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 70886554

kernel/marker.c

+5 −4
Original line number Diff line number Diff line
@@ -698,14 +698,12 @@ int marker_probe_unregister(const char *name, 
{

	struct marker_entry *entry;

	struct marker_probe_closure *old;

	int ret = 0;

	int ret = -ENOENT;



	mutex_lock(&markers_mutex);

	entry = get_marker(name);

	if (!entry) {

		ret = -ENOENT;

	if (!entry)

		goto end;

	}

	if (entry->rcu_pending)

		rcu_barrier();

	old = marker_entry_remove_probe(entry, probe, probe_private);
@@ -713,12 +711,15 @@ int marker_probe_unregister(const char *name, 
	marker_update_probes();		/* may update entry */

	mutex_lock(&markers_mutex);

	entry = get_marker(name);

	if (!entry)

		goto end;

	entry->oldptr = old;

	entry->rcu_pending = 1;

	/* write rcu_pending before calling the RCU callback */

	smp_wmb();

	call_rcu(&entry->rcu, free_old_closure);

	remove_marker(name);	/* Ignore busy error message */

	ret = 0;

end:

	mutex_unlock(&markers_mutex);

	return ret;