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authorFrederic Weisbecker <fweisbec@gmail.com>2008-10-22 19:14:55 +0200
committerIngo Molnar <mingo@elte.hu>2008-10-27 16:45:46 +0100
commitf66af459a931f25807e1df7915b2b66bb5978d82 (patch)
treebb88917429fe1ea4f6d6e088ead040b25d205a86 /kernel
parent5209f08dc8e5f520ca81b87fa9a7142f58a109f4 (diff)
tracepoint: check if the probe has been registered
Impact: fix kernel crash that can trigger during tracing If we try to remove a probe that has not been already registered, the tracepoint_entry_remove_probe() function will dereference a NULL pointer. Check the probe before removing it to avoid crashes. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/tracepoint.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index f2b7c28a4708..af8c85664882 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -131,6 +131,9 @@ tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void *probe)
old = entry->funcs;
+ if (!old)
+ return NULL;
+
debug_print_probes(entry);
/* (N -> M), (N > 1, M >= 0) probes */
for (nr_probes = 0; old[nr_probes]; nr_probes++) {
@@ -388,6 +391,11 @@ int tracepoint_probe_unregister(const char *name, void *probe)
if (entry->rcu_pending)
rcu_barrier_sched();
old = tracepoint_entry_remove_probe(entry, probe);
+ if (!old) {
+ printk(KERN_WARNING "Warning: Trying to unregister a probe"
+ "that doesn't exist\n");
+ goto end;
+ }
mutex_unlock(&tracepoints_mutex);
tracepoint_update_probes(); /* may update entry */
mutex_lock(&tracepoints_mutex);