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| author | Takashi Iwai <tiwai@suse.de> | 2021-05-18 10:39:39 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2021-05-19 16:25:57 +0200 |
| commit | 05ca447630334c323c9e2b788b61133ab75d60d3 (patch) | |
| tree | 94335e1abb5155c3e8f96c4919c8595c4e520177 /sound/usb/line6/driver.c | |
| parent | 4c6fe8c547e3c9e8c15dabdd23c569ee0df3adb1 (diff) | |
| download | lwn-05ca447630334c323c9e2b788b61133ab75d60d3.tar.gz lwn-05ca447630334c323c9e2b788b61133ab75d60d3.zip | |
ALSA: line6: Fix racy initialization of LINE6 MIDI
The initialization of MIDI devices that are found on some LINE6
drivers are currently done in a racy way; namely, the MIDI buffer
instance is allocated and initialized in each private_init callback
while the communication with the interface is already started via
line6_init_cap_control() call before that point. This may lead to
Oops in line6_data_received() when a spurious event is received, as
reported by syzkaller.
This patch moves the MIDI initialization to line6_init_cap_control()
as well instead of the too-lately-called private_init for avoiding the
race. Also this reduces slightly more lines, so it's a win-win
change.
Reported-by: syzbot+0d2b3feb0a2887862e06@syzkallerlkml..appspotmail.com
Link: https://lore.kernel.org/r/000000000000a4be9405c28520de@google.com
Link: https://lore.kernel.org/r/20210517132725.GA50495@hyeyoo
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210518083939.1927-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb/line6/driver.c')
| -rw-r--r-- | sound/usb/line6/driver.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c index a030dd65eb28..9602929b7de9 100644 --- a/sound/usb/line6/driver.c +++ b/sound/usb/line6/driver.c @@ -699,6 +699,10 @@ static int line6_init_cap_control(struct usb_line6 *line6) line6->buffer_message = kmalloc(LINE6_MIDI_MESSAGE_MAXLEN, GFP_KERNEL); if (!line6->buffer_message) return -ENOMEM; + + ret = line6_init_midi(line6); + if (ret < 0) + return ret; } else { ret = line6_hwdep_init(line6); if (ret < 0) |