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| author | Sahara <keun-o.park@windriver.com> | 2013-04-15 11:13:15 +0900 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2013-04-19 19:59:49 -0400 |
| commit | 4c69e6ea415a35eb7f0fc8ee9390c8f7436492a2 (patch) | |
| tree | 586b87d0779390d498ce45df375b97decacfb059 /kernel/tracepoint.c | |
| parent | d2802d0739dcc61af5e5ea00773ce7ddead4e9c2 (diff) | |
| download | lwn-4c69e6ea415a35eb7f0fc8ee9390c8f7436492a2.tar.gz lwn-4c69e6ea415a35eb7f0fc8ee9390c8f7436492a2.zip | |
tracepoints: Prevent null probe from being added
Somehow tracepoint_entry_add_probe() function allows a null probe function.
And, this may lead to unexpected results since the number of probe
functions in an entry can be counted by checking whether a probe is null
or not in the for-loop.
This patch prevents a null probe from being added.
In tracepoint_entry_remove_probe() function, checking probe parameter
within the for-loop is moved out for code efficiency, leaving the null probe
feature which removes all probe functions in the entry.
Link: http://lkml.kernel.org/r/1365991995-19445-1-git-send-email-kpark3469@gmail.com
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Sahara <keun-o.park@windriver.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/tracepoint.c')
| -rw-r--r-- | kernel/tracepoint.c | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index d96ba22dabfa..99e7e314e451 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -112,7 +112,8 @@ tracepoint_entry_add_probe(struct tracepoint_entry *entry, int nr_probes = 0; struct tracepoint_func *old, *new; - WARN_ON(!probe); + if (WARN_ON(!probe)) + return ERR_PTR(-EINVAL); debug_print_probes(entry); old = entry->funcs; @@ -152,13 +153,18 @@ tracepoint_entry_remove_probe(struct tracepoint_entry *entry, debug_print_probes(entry); /* (N -> M), (N > 1, M >= 0) probes */ - for (nr_probes = 0; old[nr_probes].func; nr_probes++) { - if (!probe || - (old[nr_probes].func == probe && - old[nr_probes].data == data)) - nr_del++; + if (probe) { + for (nr_probes = 0; old[nr_probes].func; nr_probes++) { + if (old[nr_probes].func == probe && + old[nr_probes].data == data) + nr_del++; + } } + /* + * If probe is NULL, then nr_probes = nr_del = 0, and then the + * entire entry will be removed. + */ if (nr_probes - nr_del == 0) { /* N -> 0, (N > 1) */ entry->funcs = NULL; @@ -173,8 +179,7 @@ tracepoint_entry_remove_probe(struct tracepoint_entry *entry, if (new == NULL) return ERR_PTR(-ENOMEM); for (i = 0; old[i].func; i++) - if (probe && - (old[i].func != probe || old[i].data != data)) + if (old[i].func != probe || old[i].data != data) new[j++] = old[i]; new[nr_probes - nr_del].func = NULL; entry->refcount = nr_probes - nr_del; |