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: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Link: https://lore.kernel.org/r/20210517132725.GA50495@hyeyoo
Cc: Hyeonggon Yoo <[email protected]>
Cc: <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Takashi Iwai <[email protected]>

0 files changed, 0 insertions, 0 deletions