On Mon, May 3, 2021 at 3:42 AM Pavel Begunkov <asml.silence@xxxxxxxxx> wrote: > > On 4/30/21 3:21 PM, Palash Oswal wrote: > > On Thursday, March 18, 2021 at 9:40:21 PM UTC+5:30 syzbot wrote: > >> > >> Hello, > >> > >> syzbot found the following issue on: > >> > >> HEAD commit: 0d7588ab riscv: process: Fix no prototype for arch_dup_tas.. > >> git tree: git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git fixes > >> console output: https://syzkaller.appspot.com/x/log.txt?x=12dde5aed00000 > >> kernel config: https://syzkaller.appspot.com/x/.config?x=81c0b708b31626cc > >> dashboard link: https://syzkaller.appspot.com/bug?extid=11bf59db879676f59e52 > >> userspace arch: riscv64 > >> CC: [asml.s...@xxxxxxxxx ax...@xxxxxxxxx io-u...@xxxxxxxxxxxxxxx linux-...@xxxxxxxxxxxxxxx] > >> > >> Unfortunately, I don't have any reproducer for this issue yet. > >> > >> IMPORTANT: if you fix the issue, please add the following tag to the commit: > >> Reported-by: syzbot+11bf59...@xxxxxxxxxxxxxxxxxxxxxxxxx > >> > >> INFO: task iou-sqp-4867:4871 blocked for more than 430 seconds. > >> Not tainted 5.12.0-rc2-syzkaller-00467-g0d7588ab9ef9 #0 > >> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > >> task:iou-sqp-4867 state:D stack: 0 pid: 4871 ppid: 4259 flags:0x00000004 > >> Call Trace: > >> [<ffffffe003bc3252>] context_switch kernel/sched/core.c:4324 [inline] > >> [<ffffffe003bc3252>] __schedule+0x478/0xdec kernel/sched/core.c:5075 > >> [<ffffffe003bc3c2a>] schedule+0x64/0x166 kernel/sched/core.c:5154 > >> [<ffffffe0004b80ee>] io_uring_cancel_sqpoll+0x1de/0x294 fs/io_uring.c:8858 > >> [<ffffffe0004c19cc>] io_sq_thread+0x548/0xe58 fs/io_uring.c:6750 > >> [<ffffffe000005570>] ret_from_exception+0x0/0x14 > > The test might be very useful. Would you send a patch to > liburing? Or mind the repro being taken as a test? > > Pavel, I'm working on a PR for liburing with this test. Do you know how I can address this behavior? root@syzkaller:~/liburing/test# ./runtests.sh sqpoll-cancel-hang Running test sqp[ 15.310997] Running test sqpoll-cancel-hang: oll-cancel-hang: [ 15.333348] sqpoll-cancel-h[305]: segfault at 0 ip 000055ad00e265e3 sp] [ 15.334940] Code: 89 d8 8d 34 90 8b 45 04 ba 03 00 00 00 c1 e0 04 03 46 All tests passed root@syzkaller:~/liburing/test# ./sqpoll-cancel-hang [ 13.572639] sqpoll-cancel-h[298]: segfault at 0 ip 00005634c4a455e3 sp] [ 13.576506] Code: 89 d8 8d 34 90 8b 45 04 ba 03 00 00 00 c1 e0 04 03 46 [ 23.350459] random: crng init done [ 23.352837] random: 7 urandom warning(s) missed due to ratelimiting [ 243.090865] INFO: task iou-sqp-298:299 blocked for more than 120 secon. [ 243.095187] Not tainted 5.12.0 #142 [ 243.099800] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disable. [ 243.105928] task:iou-sqp-298 state:D stack: 0 pid: 299 ppid: 4 [ 243.111044] Call Trace: [ 243.112855] __schedule+0xb1d/0x1130 [ 243.115549] ? __sched_text_start+0x8/0x8 [ 243.118328] ? io_wq_worker_sleeping+0x145/0x500 [ 243.121790] schedule+0x131/0x1c0 [ 243.123698] io_uring_cancel_sqpoll+0x288/0x350 [ 243.125977] ? io_sq_thread_unpark+0xd0/0xd0 [ 243.128966] ? mutex_lock+0xbb/0x130 [ 243.132572] ? init_wait_entry+0xe0/0xe0 [ 243.135429] ? wait_for_completion_killable_timeout+0x20/0x20 [ 243.138303] io_sq_thread+0x174c/0x18c0 [ 243.140162] ? io_rsrc_put_work+0x380/0x380 [ 243.141613] ? init_wait_entry+0xe0/0xe0 [ 243.143686] ? _raw_spin_lock_irq+0xa5/0x180 [ 243.145619] ? _raw_spin_lock_irqsave+0x190/0x190 [ 243.147671] ? calculate_sigpending+0x6b/0xa0 [ 243.149036] ? io_rsrc_put_work+0x380/0x380 [ 243.150694] ret_from_fork+0x22/0x30 Palash
