Messages in this thread Patch in this message | | | Subject | [PATCH 2/6] tracepoint: Check if the probe has been registered | From | Frederic Weisbecker <> | Date | Fri, 10 Oct 2008 13:16:31 |
| |
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> --- kernel/tracepoint.c | 8 ++++++++ 1 files changed, 8 insertions(+), 0 deletions(-)
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index f2b7c28..af8c856 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);
| |