diff options
| author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-09-19 09:12:41 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-09-19 09:12:41 +0200 |
| commit | c51f2ff0075b77f272da93b7155aa666a77c8fe7 (patch) | |
| tree | f229265a8d4b0407f2eaaa4fb6d1afb86ac380c5 /kernel/events/ring_buffer.c | |
| parent | eddde288957957d45c42fcf51af9a059de7e0887 (diff) | |
| parent | 3be7988674ab33565700a37b210f502563d932e6 (diff) | |
Merge 4.8-rc7 into usb-next
We want/need the USB fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/events/ring_buffer.c')
| -rw-r--r-- | kernel/events/ring_buffer.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c index ae9b90dc9a5a..257fa460b846 100644 --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -330,15 +330,22 @@ void *perf_aux_output_begin(struct perf_output_handle *handle, if (!rb) return NULL; - if (!rb_has_aux(rb) || !atomic_inc_not_zero(&rb->aux_refcount)) + if (!rb_has_aux(rb)) goto err; /* - * If rb::aux_mmap_count is zero (and rb_has_aux() above went through), - * the aux buffer is in perf_mmap_close(), about to get freed. + * If aux_mmap_count is zero, the aux buffer is in perf_mmap_close(), + * about to get freed, so we leave immediately. + * + * Checking rb::aux_mmap_count and rb::refcount has to be done in + * the same order, see perf_mmap_close. Otherwise we end up freeing + * aux pages in this path, which is a bug, because in_atomic(). */ if (!atomic_read(&rb->aux_mmap_count)) - goto err_put; + goto err; + + if (!atomic_inc_not_zero(&rb->aux_refcount)) + goto err; /* * Nesting is not supported for AUX area, make sure nested |