There are use-after-free bugs caused by tst_timer. The root cause
is that there are no functions to stop tst_timer in idt77252_exit().
One of the possible race conditions is shown below:
(thread 1) | (thread 2)
| idt77252_init_one
| init_card
| fill_tst
| mod_timer(&card->tst_timer, ...)
idt77252_exit | (wait a time)
| tst_timer
|
| ...
kfree(card) // FREE |
| card->soft_tst[e] // USE
The idt77252_dev is deallocated in idt77252_exit() and used in
timer handler.
This patch adds del_timer_sync() in idt77252_exit() in order that
the timer handler could be stopped before the idt77252_dev is
deallocated.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Link: https://lore.kernel.org/r/20220805070008.18007-1-duoming@zju.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
3f4093e2bf