On Tue, Feb 27, 2018 at 10:59 PM, Yisheng Xie <xieyisheng1@xxxxxxxxxx> wrote: > ashmem_mutex may create a chain of dependencies like: > > CPU0 CPU1 > mmap syscall ioctl syscall > -> mmap_sem (acquired) -> ashmem_ioctl > -> ashmem_mmap -> ashmem_mutex (acquired) > -> ashmem_mutex (try to acquire) -> copy_from_user > -> mmap_sem (try to acquire) > > There is a lock odering problem between mmap_sem and ashmem_mutex causing > a lockdep splat[1] during a syzcaller test. This patch fixes the problem > by move copy_from_user out of ashmem_mutex. > > [1] https://www.spinics.net/lists/kernel/msg2733200.html > > Fixes: ce8a3a9e76d0 (staging: android: ashmem: Fix a race condition in pin ioctls) > Reported-by: syzbot+d7a918a7a8e1c952bc36@xxxxxxxxxxxxxxxxxxxxxxxxx > Signed-off-by: Yisheng Xie <xieyisheng1@xxxxxxxxxx> Greg, Could you take this patch for the stable trees? I do see it in staging already. I couldn't find it in stable so wanted to bring it to your attention. If you already aware of it, please ignore my note. Thanks, - Joel _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
