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| author | Frederic Weisbecker <fweisbec@gmail.com> | 2008-10-22 19:14:55 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-10-27 16:45:46 +0100 |
| commit | f66af459a931f25807e1df7915b2b66bb5978d82 (patch) | |
| tree | bb88917429fe1ea4f6d6e088ead040b25d205a86 /kernel/tracepoint.c | |
| parent | 5209f08dc8e5f520ca81b87fa9a7142f58a109f4 (diff) | |
| download | lwn-f66af459a931f25807e1df7915b2b66bb5978d82.tar.gz lwn-f66af459a931f25807e1df7915b2b66bb5978d82.zip | |
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/tracepoint.c')
| -rw-r--r-- | kernel/tracepoint.c | 8 |
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); |