syzbot has found a reproducer for the following issue on: HEAD commit: 04fe99a8d936 Add linux-next specific files for 20211207 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=1315e2b9b00000 kernel config: https://syzkaller.appspot.com/x/.config?x=4589399873466942 dashboard link: https://syzkaller.appspot.com/bug?extid=643e4ce4b6ad1347d372 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11bb96ceb00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15ad1badb00000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+643e4ce4b6ad1347d372@xxxxxxxxxxxxxxxxxxxxxxxxx ====================================================== WARNING: possible circular locking dependency detected 5.16.0-rc4-next-20211207-syzkaller #0 Not tainted ------------------------------------------------------ systemd-udevd/7081 is trying to acquire lock: ffff88802358c938 ((wq_completion)loop3){+.+.}-{0:0}, at: flush_workqueue+0xe1/0x15b0 kernel/workqueue.c:2835 but task is already holding lock: ffff88801a57a118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0x99/0x980 block/bdev.c:907 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #6 (&disk->open_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:607 [inline] __mutex_lock+0x12f/0x12f0 kernel/locking/mutex.c:740 blkdev_get_by_dev.part.0+0x40e/0xc70 block/bdev.c:809 blkdev_get_by_dev+0x6b/0x80 block/bdev.c:852 swsusp_check+0x97/0x2f0 kernel/power/swap.c:1520 software_resume.part.0+0x102/0x1f0 kernel/power/hibernate.c:979 software_resume kernel/power/hibernate.c:86 [inline] resume_store+0x161/0x190 kernel/power/hibernate.c:1181 kobj_attr_store+0x50/0x80 lib/kobject.c:856 sysfs_kf_write+0x110/0x160 fs/sysfs/file.c:136 kernfs_fop_write_iter+0x342/0x500 fs/kernfs/file.c:296 call_write_iter include/linux/fs.h:2079 [inline] new_sync_write+0x429/0x660 fs/read_write.c:503 vfs_write+0x7cd/0xae0 fs/read_write.c:590 ksys_write+0x12d/0x250 fs/read_write.c:643 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #5 (system_transition_mutex/1){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:607 [inline] __mutex_lock+0x12f/0x12f0 kernel/locking/mutex.c:740 software_resume.part.0+0x19/0x1f0 kernel/power/hibernate.c:934 software_resume kernel/power/hibernate.c:86 [inline] resume_store+0x161/0x190 kernel/power/hibernate.c:1181 kobj_attr_store+0x50/0x80 lib/kobject.c:856 sysfs_kf_write+0x110/0x160 fs/sysfs/file.c:136 kernfs_fop_write_iter+0x342/0x500 fs/kernfs/file.c:296 call_write_iter include/linux/fs.h:2079 [inline] new_sync_write+0x429/0x660 fs/read_write.c:503 vfs_write+0x7cd/0xae0 fs/read_write.c:590 ksys_write+0x12d/0x250 fs/read_write.c:643 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #4 (&of->mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:607 [inline] __mutex_lock+0x12f/0x12f0 kernel/locking/mutex.c:740 kernfs_seq_start+0x4b/0x260 fs/kernfs/file.c:112 seq_read_iter+0x2c7/0x1240 fs/seq_file.c:225 kernfs_fop_read_iter+0x44f/0x5f0 fs/kernfs/file.c:241 call_read_iter include/linux/fs.h:2073 [inline] new_sync_read+0x421/0x6e0 fs/read_write.c:400 vfs_read+0x35c/0x600 fs/read_write.c:481 ksys_read+0x12d/0x250 fs/read_write.c:619 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #3 (&p->lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:607 [inline] __mutex_lock+0x12f/0x12f0 kernel/locking/mutex.c:740 seq_read_iter+0xdf/0x1240 fs/seq_file.c:182 call_read_iter include/linux/fs.h:2073 [inline] generic_file_splice_read+0x453/0x6d0 fs/splice.c:311 do_splice_to+0x1bf/0x250 fs/splice.c:796 splice_direct_to_actor+0x2c2/0x8c0 fs/splice.c:870 do_splice_direct+0x1b3/0x280 fs/splice.c:979 do_sendfile+0xaf2/0x1250 fs/read_write.c:1245 __do_sys_sendfile64 fs/read_write.c:1310 [inline] __se_sys_sendfile64 fs/read_write.c:1296 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1296 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #2 (sb_writers#3){.+.+}-{0:0}: percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1727 [inline] sb_start_write include/linux/fs.h:1797 [inline] file_start_write include/linux/fs.h:2942 [inline] lo_write_bvec drivers/block/loop.c:242 [inline] lo_write_simple drivers/block/loop.c:265 [inline] do_req_filebacked drivers/block/loop.c:494 [inline] loop_handle_cmd drivers/block/loop.c:1846 [inline] loop_process_work+0x1499/0x1db0 drivers/block/loop.c:1886 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2318 worker_thread+0x658/0x11f0 kernel/workqueue.c:2465 kthread+0x405/0x4f0 kernel/kthread.c:345 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 -> #1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}: process_one_work+0x921/0x1690 kernel/workqueue.c:2294 worker_thread+0x658/0x11f0 kernel/workqueue.c:2465 kthread+0x405/0x4f0 kernel/kthread.c:345 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 -> #0 ((wq_completion)loop3){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3063 [inline] check_prevs_add kernel/locking/lockdep.c:3186 [inline] validate_chain kernel/locking/lockdep.c:3801 [inline] __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5027 lock_acquire kernel/locking/lockdep.c:5637 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5602 flush_workqueue+0x110/0x15b0 kernel/workqueue.c:2838 drain_workqueue+0x1a5/0x3c0 kernel/workqueue.c:3003 destroy_workqueue+0x71/0x800 kernel/workqueue.c:4440 __loop_clr_fd+0x1ab/0xe20 drivers/block/loop.c:1118 lo_release+0x1ac/0x1f0 drivers/block/loop.c:1750 blkdev_put_whole block/bdev.c:694 [inline] blkdev_put+0x2de/0x980 block/bdev.c:949 blkdev_close+0x6a/0x80 block/fops.c:516 __fput+0x286/0x9f0 fs/file_table.c:311 task_work_run+0xdd/0x1a0 kernel/task_work.c:164 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:175 [inline] exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae other info that might help us debug this: Chain exists of: (wq_completion)loop3 --> system_transition_mutex/1 --> &disk->open_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&disk->open_mutex); lock(system_transition_mutex/1); lock(&disk->open_mutex); lock((wq_completion)loop3); *** DEADLOCK *** 1 lock held by systemd-udevd/7081: #0: ffff88801a57a118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0x99/0x980 block/bdev.c:907 stack backtrace: CPU: 1 PID: 7081 Comm: systemd-udevd Not tainted 5.16.0-rc4-next-20211207-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2143 check_prev_add kernel/locking/lockdep.c:3063 [inline] check_prevs_add kernel/locking/lockdep.c:3186 [inline] validate_chain kernel/locking/lockdep.c:3801 [inline] __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5027 lock_acquire kernel/locking/lockdep.c:5637 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5602 flush_workqueue+0x110/0x15b0 kernel/workqueue.c:2838 drain_workqueue+0x1a5/0x3c0 kernel/workqueue.c:3003 destroy_workqueue+0x71/0x800 kernel/workqueue.c:4440 __loop_clr_fd+0x1ab/0xe20 drivers/block/loop.c:1118 lo_release+0x1ac/0x1f0 drivers/block/loop.c:1750 blkdev_put_whole block/bdev.c:694 [inline] blkdev_put+0x2de/0x980 block/bdev.c:949 blkdev_close+0x6a/0x80 block/fops.c:516 __fput+0x286/0x9f0 fs/file_table.c:311 task_work_run+0xdd/0x1a0 kernel/task_work.c:164 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:175 [inline] exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f5387c2b270 Code: 73 01 c3 48 8b 0d 38 7d 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 59 c1 20 00 00 75 10 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 ee fb ff ff 48 89 04 24 RSP: 002b:00007ffce06abcb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007f5387c2b270 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000007 RBP: 00007f5388ae5710 R08: 00005621f86a7af0 R09: 00005621f86b5700 R10: 00007f5388ae58c0 R11: 0000000000000246 R12: 0000000000000000 R13: 00005621f86a3e40 R14: 0000000000000003 R15: 000000000000000e </TASK> I/O error, dev loop2, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 I/O error, dev loop2, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 I/O error, dev loop2, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0 Buffer I/O error on dev loop2, logical block 0, async page read I/O error, dev loop3, sector 1 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0 Buffer I/O error on dev loop3, logical block 1, async page read I/O error, dev loop3, sector 1 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0 Buffer I/O error on dev loop3, logical block 1, async page read
