On 1/27/19 1:05 AM, Dmitry Vyukov wrote: > On Sun, Jan 27, 2019 at 9:01 AM syzbot > <syzbot+4df6ca820108fd248943@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: >> >> Hello, >> >> syzbot found the following crash on: >> >> HEAD commit: 7930851ef10c Merge tag 'scsi-fixes' of git://git.kernel.or.. >> git tree: upstream >> console output: https://syzkaller.appspot.com/x/log.txt?x=1002c77f400000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=505743eba4e4f68 >> dashboard link: https://syzkaller.appspot.com/bug?extid=4df6ca820108fd248943 >> compiler: gcc (GCC) 9.0.0 20181231 (experimental) >> >> Unfortunately, I don't have any reproducer for this crash yet. >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+4df6ca820108fd248943@xxxxxxxxxxxxxxxxxxxxxxxxx > > > Mainline tree crashes on boot. > +generic_make_request maintainers > > [ 7.485069] ================================================================== > [ 7.486411] BUG: KASAN: use-after-free in generic_make_request+0x14dd/0x1810 > [ 7.487539] Read of size 2 at addr ffff8880a39618d4 by task swapper/0/1 > [ 7.488689] Ah duh, not sure how I missed that: + bio_set_flag(bio, BIO_QUEUE_ENTERED); ret = q->make_request_fn(q, bio); + bio_clear_flag(bio, BIO_QUEUE_ENTERED); Ming, we can't touch bio after ->make_request_fn(), it could very well be completed already. -- Jens Axboe
