On Wed, 03 Nov 2021 16:52:31 +0100, Takashi Iwai wrote: > > On Wed, 03 Nov 2021 04:35:17 +0100, > Wang Wensheng wrote: > > > > When the timer instance was add into ack_list but was not currently in > > process, the user could stop it via snd_timer_stop1() without delete it > > from the ack_list. Then the user could free the timer instance and when > > it was actually processed UAF occurred. > > > > This issue could be reproduced via testcase snd_timer01 in ltp - running > > several instances of that testcase at the same time. > > > > What I actually met was that the ack_list of the timer broken and the > > kernel went into deadloop with irqoff. That could be detected by > > hardlockup detector on board or when we run it on qemu, we could use gdb > > to dump the ack_list when the console has no response. > > > > To fix this issue, we delete the timer instance from ack_list and > > active_list unconditionally in snd_timer_stop1(). > > > > Signed-off-by: Wang Wensheng <wangwensheng4@xxxxxxxxxx> > > Suggested-by: Takashi Iwai <tiwai@xxxxxxx> > > Thanks, applied now. BTW, while reviewing the patch, I noticed that we have also the similar code path for a slave timer instance that has the same kind of linked list entries. I'll submit the corresponding fix patch. Takashi
