On 2/25/21 9:48 AM, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 7f206cf3 Add linux-next specific files for 20210225 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=16d9516cd00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=a1746d2802a82a05 > dashboard link: https://syzkaller.appspot.com/bug?extid=c927c937cba8ef66dd4a > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13b9c5a8d00000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+c927c937cba8ef66dd4a@xxxxxxxxxxxxxxxxxxxxxxxxx > > INFO: task syz-executor.0:12538 can't die for more than 143 seconds. > task:syz-executor.0 state:D stack:28352 pid:12538 ppid: 8423 flags:0x00004004 > Call Trace: > context_switch kernel/sched/core.c:4324 [inline] > __schedule+0x90c/0x21a0 kernel/sched/core.c:5075 > schedule+0xcf/0x270 kernel/sched/core.c:5154 > schedule_timeout+0x1db/0x250 kernel/time/timer.c:1868 > do_wait_for_common kernel/sched/completion.c:85 [inline] > __wait_for_common kernel/sched/completion.c:106 [inline] > wait_for_common kernel/sched/completion.c:117 [inline] > wait_for_completion+0x168/0x270 kernel/sched/completion.c:138 > io_sq_thread_finish+0x96/0x580 fs/io_uring.c:7152 > io_sq_offload_create fs/io_uring.c:7929 [inline] > io_uring_create fs/io_uring.c:9465 [inline] > io_uring_setup+0x1fb2/0x2c20 fs/io_uring.c:9550 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xae > RIP: 0033:0x465ef9 > RSP: 002b:00007fe26f744108 EFLAGS: 00000202 ORIG_RAX: 00000000000001a9 > RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465ef9 > RDX: 0000000020ffd000 RSI: 0000000020000040 RDI: 000000000000563c > RBP: 0000000020000040 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 > R13: 0000000020ffd000 R14: 0000000000000000 R15: 0000000020ffc000 > INFO: task syz-executor.0:12538 blocked for more than 143 seconds. > Not tainted 5.11.0-next-20210225-syzkaller #0 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > task:syz-executor.0 state:D stack:28352 pid:12538 ppid: 8423 flags:0x00004004 > Call Trace: > context_switch kernel/sched/core.c:4324 [inline] > __schedule+0x90c/0x21a0 kernel/sched/core.c:5075 > schedule+0xcf/0x270 kernel/sched/core.c:5154 > schedule_timeout+0x1db/0x250 kernel/time/timer.c:1868 > do_wait_for_common kernel/sched/completion.c:85 [inline] > __wait_for_common kernel/sched/completion.c:106 [inline] > wait_for_common kernel/sched/completion.c:117 [inline] > wait_for_completion+0x168/0x270 kernel/sched/completion.c:138 > io_sq_thread_finish+0x96/0x580 fs/io_uring.c:7152 > io_sq_offload_create fs/io_uring.c:7929 [inline] > io_uring_create fs/io_uring.c:9465 [inline] > io_uring_setup+0x1fb2/0x2c20 fs/io_uring.c:9550 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xae > RIP: 0033:0x465ef9 > RSP: 002b:00007fe26f744108 EFLAGS: 00000202 ORIG_RAX: 00000000000001a9 > RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465ef9 > RDX: 0000000020ffd000 RSI: 0000000020000040 RDI: 000000000000563c > RBP: 0000000020000040 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 > R13: 0000000020ffd000 R14: 0000000000000000 R15: 0000000020ffc000 > INFO: task iou-sqp-12538:12557 can't die for more than 143 seconds. > task:iou-sqp-12538 state:D stack:30296 pid:12557 ppid: 8423 flags:0x00004004 > Call Trace: > context_switch kernel/sched/core.c:4324 [inline] > __schedule+0x90c/0x21a0 kernel/sched/core.c:5075 > schedule+0xcf/0x270 kernel/sched/core.c:5154 > schedule_timeout+0x1db/0x250 kernel/time/timer.c:1868 > do_wait_for_common kernel/sched/completion.c:85 [inline] > __wait_for_common kernel/sched/completion.c:106 [inline] > wait_for_common kernel/sched/completion.c:117 [inline] > wait_for_completion+0x168/0x270 kernel/sched/completion.c:138 > io_sq_thread+0x27d/0x19a0 fs/io_uring.c:6731 > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 > INFO: task iou-sqp-12538:12557 blocked for more than 143 seconds. > Not tainted 5.11.0-next-20210225-syzkaller #0 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > task:iou-sqp-12538 state:D stack:30296 pid:12557 ppid: 8423 flags:0x00004004 > Call Trace: > context_switch kernel/sched/core.c:4324 [inline] > __schedule+0x90c/0x21a0 kernel/sched/core.c:5075 > schedule+0xcf/0x270 kernel/sched/core.c:5154 > schedule_timeout+0x1db/0x250 kernel/time/timer.c:1868 > do_wait_for_common kernel/sched/completion.c:85 [inline] > __wait_for_common kernel/sched/completion.c:106 [inline] > wait_for_common kernel/sched/completion.c:117 [inline] > wait_for_completion+0x168/0x270 kernel/sched/completion.c:138 > io_sq_thread+0x27d/0x19a0 fs/io_uring.c:6731 > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 > > Showing all locks held in the system: > 1 lock held by khungtaskd/1653: > #0: ffffffff8bf744e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6327 > 1 lock held by in:imklog/8109: > #0: ffff8880126b65f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:961 > 2 locks held by kworker/u4:3/8814: > > ============================================= > > NMI backtrace for cpu 0 > CPU: 0 PID: 1653 Comm: khungtaskd Not tainted 5.11.0-next-20210225-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:79 [inline] > dump_stack+0xfa/0x151 lib/dump_stack.c:120 > nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 > nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 > trigger_all_cpu_backtrace include/linux/nmi.h:147 [inline] > check_hung_uninterruptible_tasks kernel/hung_task.c:253 [inline] > watchdog+0xd8e/0xf40 kernel/hung_task.c:338 > kthread+0x3b1/0x4a0 kernel/kthread.c:292 > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 > Sending NMI from CPU 0 to CPUs 1: > NMI backtrace for cpu 1 > CPU: 1 PID: 10404 Comm: kworker/u4:9 Not tainted 5.11.0-next-20210225-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Workqueue: phy14 ieee80211_iface_work > RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:163 [inline] > RIP: 0010:unwind_next_frame+0x238/0x2000 arch/x86/kernel/unwind_orc.c:443 > Code: ff 39 d6 0f 83 69 12 00 00 48 ba 00 00 00 00 00 fc ff df 41 89 f0 4a 8d 3c 85 08 a7 d7 8e 49 89 f9 49 c1 e9 03 45 0f b6 0c 11 <48> 89 fa 83 e2 07 83 c2 03 44 38 ca 7c 32 45 84 c9 74 2d 4c 89 44 > RSP: 0018:ffffc9000c146d18 EFLAGS: 00000a02 > RAX: 0000000000000000 RBX: 1ffff92001828dab RCX: ffffffff81325e95 > RDX: dffffc0000000000 RSI: 000000000000325e RDI: ffffffff8ed87080 > RBP: 0000000000000001 R08: 000000000000325e R09: 0000000000000000 > R10: 0000000000084087 R11: 0000000000000000 R12: ffffc9000c146e88 > R13: ffffc9000c146e75 R14: ffffc9000c146e90 R15: ffffc9000c146e40 > FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007fd5c6299010 CR3: 0000000026149000 CR4: 00000000001506e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > __unwind_start+0x51b/0x800 arch/x86/kernel/unwind_orc.c:699 > unwind_start arch/x86/include/asm/unwind.h:60 [inline] > arch_stack_walk+0x5c/0xe0 arch/x86/kernel/stacktrace.c:24 > stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:121 > kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 > kasan_set_track mm/kasan/common.c:46 [inline] > set_alloc_info mm/kasan/common.c:427 [inline] > ____kasan_kmalloc mm/kasan/common.c:506 [inline] > ____kasan_kmalloc mm/kasan/common.c:465 [inline] > __kasan_kmalloc+0x99/0xc0 mm/kasan/common.c:515 > kmalloc include/linux/slab.h:559 [inline] > ieee802_11_parse_elems_crc+0x121/0xfe0 net/mac80211/util.c:1473 > ieee802_11_parse_elems net/mac80211/ieee80211_i.h:2041 [inline] > ieee80211_bss_info_update+0x4b4/0xb20 net/mac80211/scan.c:212 > ieee80211_rx_bss_info net/mac80211/ibss.c:1126 [inline] > ieee80211_rx_mgmt_probe_beacon+0xccd/0x16b0 net/mac80211/ibss.c:1615 > ieee80211_ibss_rx_queued_mgmt+0xe43/0x1870 net/mac80211/ibss.c:1642 > ieee80211_iface_work+0x761/0x9e0 net/mac80211/iface.c:1439 > process_one_work+0x98d/0x1600 kernel/workqueue.c:2275 > worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 > kthread+0x3b1/0x4a0 kernel/kthread.c:292 > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Looks like an error introduced in the switch, can you see if this helps? diff --git a/fs/io_uring.c b/fs/io_uring.c index 15a9c59e9a13..fc7137aea698 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -7135,6 +7135,7 @@ static void io_sq_thread_finish(struct io_ring_ctx *ctx) struct io_sq_data *sqd = ctx->sq_data; if (sqd) { + complete(&sqd->startup); if (sqd->thread) { wait_for_completion(&ctx->sq_thread_comp); io_sq_thread_park(sqd); -- Jens Axboe
