Hello, syzbot found the following issue on: HEAD commit: fb0155a0 Merge tag 'nfs-for-5.9-3' of git://git.linux-nfs... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1527329d900000 kernel config: https://syzkaller.appspot.com/x/.config?x=41b736b7ce1b3ea4 dashboard link: https://syzkaller.appspot.com/bug?extid=9a29d5e745bd7523c851 compiler: gcc (GCC) 10.1.0-syz 20200507 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13cb63e3900000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17ae6083900000 The issue was bisected to: commit 2da22da573481cc4837e246d0eee4d518b3f715e Author: Mike Christie <mchristi@xxxxxxxxxx> Date: Tue Aug 13 16:39:52 2019 +0000 nbd: fix zero cmd timeout handling v2 bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=14e51b27900000 final oops: https://syzkaller.appspot.com/x/report.txt?x=16e51b27900000 console output: https://syzkaller.appspot.com/x/log.txt?x=12e51b27900000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+9a29d5e745bd7523c851@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 2da22da57348 ("nbd: fix zero cmd timeout handling v2") INFO: task syz-executor931:6875 blocked for more than 143 seconds. Not tainted 5.9.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor931 state:D stack:27640 pid: 6875 ppid: 6874 flags:0x80004006 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0xec9/0x2280 kernel/sched/core.c:4527 schedule+0xd0/0x2a0 kernel/sched/core.c:4602 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x3e2/0x10e0 kernel/locking/mutex.c:1103 blkdev_put+0x30/0x520 fs/block_dev.c:1804 blkdev_close+0x8c/0xb0 fs/block_dev.c:1853 __fput+0x285/0x920 fs/file_table.c:281 task_work_run+0xdd/0x190 kernel/task_work.c:141 exit_task_work include/linux/task_work.h:25 [inline] do_exit+0xb7d/0x29f0 kernel/exit.c:806 do_group_exit+0x125/0x310 kernel/exit.c:903 get_signal+0x428/0x1f00 kernel/signal.c:2757 arch_do_signal+0x82/0x2520 arch/x86/kernel/signal.c:811 exit_to_user_mode_loop kernel/entry/common.c:161 [inline] exit_to_user_mode_prepare+0x1ae/0x200 kernel/entry/common.c:192 syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:267 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x445039 Code: Bad RIP value. RSP: 002b:00007ffdc5595ec8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: fffffffffffffe00 RBX: 0000000000000000 RCX: 0000000000445039 RDX: 00000000ffffffff RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 00000000006cf018 R08: 00000000004002e0 R09: 00000000004002e0 R10: 00000000004002e0 R11: 0000000000000246 R12: 0000000000402200 R13: 0000000000402290 R14: 0000000000000000 R15: 0000000000000000 INFO: task systemd-udevd:6879 blocked for more than 143 seconds. Not tainted 5.9.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:systemd-udevd state:D stack:26264 pid: 6879 ppid: 3932 flags:0x00004100 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0xec9/0x2280 kernel/sched/core.c:4527 schedule+0xd0/0x2a0 kernel/sched/core.c:4602 io_schedule+0xb5/0x120 kernel/sched/core.c:6296 wait_on_page_bit_common+0x32a/0xe30 mm/filemap.c:1253 wait_on_page_bit mm/filemap.c:1314 [inline] wait_on_page_locked include/linux/pagemap.h:611 [inline] wait_on_page_read mm/filemap.c:2931 [inline] do_read_cache_page+0x957/0x1390 mm/filemap.c:2974 read_mapping_page include/linux/pagemap.h:437 [inline] read_part_sector+0xf6/0x5af block/partitions/core.c:777 adfspart_check_ICS+0x9d/0xc90 block/partitions/acorn.c:360 check_partition block/partitions/core.c:140 [inline] blk_add_partitions+0x45c/0xe40 block/partitions/core.c:705 bdev_disk_changed+0x1ea/0x370 fs/block_dev.c:1416 __blkdev_get+0xee4/0x1aa0 fs/block_dev.c:1559 blkdev_get fs/block_dev.c:1639 [inline] blkdev_open+0x227/0x300 fs/block_dev.c:1753 do_dentry_open+0x4b9/0x11b0 fs/open.c:817 do_open fs/namei.c:3251 [inline] path_openat+0x1b9a/0x2730 fs/namei.c:3368 do_filp_open+0x17e/0x3c0 fs/namei.c:3395 do_sys_openat2+0x16d/0x420 fs/open.c:1168 do_sys_open fs/open.c:1184 [inline] __do_sys_open fs/open.c:1192 [inline] __se_sys_open fs/open.c:1188 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1188 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fd8b1526840 Code: Bad RIP value. RSP: 002b:00007ffc6e5f3668 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 000055f1c1bb6e40 RCX: 00007fd8b1526840 RDX: 000055f1c0593fe3 RSI: 00000000000a0800 RDI: 000055f1c1bb9b10 RBP: 00007ffc6e5f37e0 R08: 000055f1c0593670 R09: 0000000000000010 R10: 000055f1c0593d0c R11: 0000000000000246 R12: 00007ffc6e5f3730 R13: 000055f1c1bb1a90 R14: 0000000000000003 R15: 000000000000000e Showing all locks held in the system: 1 lock held by khungtaskd/1174: #0: ffffffff8a067f40 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5852 1 lock held by in:imklog/6556: #0: ffff88809144e370 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:930 1 lock held by syz-executor931/6875: #0: ffff88808927b6c0 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_put+0x30/0x520 fs/block_dev.c:1804 1 lock held by systemd-udevd/6879: #0: ffff88808927b6c0 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x4b8/0x1aa0 fs/block_dev.c:1492 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1174 Comm: khungtaskd Not tainted 5.9.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x198/0x1fd lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0xd7d/0x1000 kernel/hung_task.c:295 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 3911 Comm: systemd-journal Not tainted 5.9.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:0xffffffffa00185f0 Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc <0f> 1f 44 00 00 55 48 89 e5 48 81 ec 00 00 00 00 53 41 55 41 56 41 RSP: 0018:ffffc90003817d88 EFLAGS: 00000246 RAX: 1ffff920001c3e06 RBX: ffff8880a7b97c00 RCX: dffffc0000000000 RDX: ffff8880a77602c0 RSI: ffffc90000e1f038 RDI: ffffc90003817e38 RBP: ffffc90000e1f000 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: 00000000000001a0 R14: 0000000000080042 R15: ffffc90003817e38 FS: 00007fa30091e8c0(0000) GS:ffff8880ae400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa2fdcde010 CR3: 00000000a8f90000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches
