bisecting fixing commit since 2034d6f0838e465dd8f120c4e946d8444b4bb5df building syzkaller on 6a81331a1d4c744da9204d02ec88d558f7eea9c9 testing commit 2034d6f0838e465dd8f120c4e946d8444b4bb5df with gcc (GCC) 8.4.1 20210217 kernel signature: 3ddccf19724534f57f10d623a9aadfcfbcbad353afeb3bf79ba45d82eaf88e60 run #0: crashed: INFO: task hung in __get_super run #1: crashed: INFO: task hung in __get_super run #2: crashed: INFO: task hung in __get_super run #3: crashed: INFO: task hung in __get_super run #4: crashed: INFO: task hung in __blkdev_get run #5: crashed: INFO: task hung in __get_super run #6: crashed: INFO: task hung in __get_super run #7: crashed: INFO: task hung in __blkdev_get run #8: crashed: INFO: task hung in __blkdev_get run #9: crashed: INFO: task hung in __blkdev_get run #10: crashed: INFO: task hung in __get_super run #11: crashed: INFO: task hung in __blkdev_get run #12: crashed: INFO: task hung in __blkdev_get run #13: crashed: INFO: task hung in __get_super run #14: crashed: INFO: task hung in __get_super run #15: crashed: INFO: task hung in __blkdev_get run #16: crashed: INFO: task hung in __blkdev_get run #17: crashed: INFO: task hung in __get_super run #18: crashed: INFO: task hung in __get_super run #19: crashed: INFO: task hung in __blkdev_get testing current HEAD 3c8c23092588a23bf1856a64f58c37f477a413be testing commit 3c8c23092588a23bf1856a64f58c37f477a413be with gcc (GCC) 8.4.1 20210217 kernel signature: e79c11e05b833f88cd04194c68bd568a4080e6c03f9e5caa07668924ded2db8f run #0: crashed: INFO: task hung in __blkdev_get run #1: crashed: INFO: task hung in __blkdev_get run #2: crashed: INFO: task hung in __blkdev_get run #3: crashed: INFO: task hung in __get_super run #4: crashed: INFO: task hung in __blkdev_get run #5: crashed: INFO: task hung in __get_super run #6: crashed: INFO: task hung in __get_super run #7: crashed: INFO: task hung in __get_super run #8: crashed: INFO: task hung in __blkdev_get run #9: crashed: INFO: task hung in __blkdev_get revisions tested: 2, total time: 38m45.211550148s (build: 25m49.031850477s, test: 12m22.374141266s) the crash still happens on HEAD commit msg: Linux 4.19.190 crash: INFO: task hung in __blkdev_get Bluetooth: hci3: command 0x0406 tx timeout Bluetooth: hci0: command 0x0406 tx timeout Bluetooth: hci5: command 0x0406 tx timeout ieee802154 phy0 wpan0: encryption failed: -22 ieee802154 phy1 wpan1: encryption failed: -22 INFO: task systemd-udevd:4699 blocked for more than 140 seconds. Not tainted 4.19.190-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. systemd-udevd D24584 4699 1 0x00000100 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3619 __mutex_lock_common kernel/locking/mutex.c:1005 [inline] __mutex_lock+0x4c3/0x1200 kernel/locking/mutex.c:1075 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1090 __blkdev_get+0x19a/0x1200 fs/block_dev.c:1478 blkdev_get+0x271/0x8c0 fs/block_dev.c:1627 blkdev_open+0x19f/0x200 fs/block_dev.c:1788 do_dentry_open+0x3f1/0x1020 fs/open.c:796 vfs_open+0x9a/0xc0 fs/open.c:902 do_last fs/namei.c:3421 [inline] path_openat+0x925/0x2900 fs/namei.c:3537 do_filp_open+0x177/0x250 fs/namei.c:3567 do_sys_open+0x1dc/0x350 fs/open.c:1085 __do_sys_open fs/open.c:1103 [inline] __se_sys_open fs/open.c:1098 [inline] __x64_sys_open+0x79/0xb0 fs/open.c:1098 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f8295b77840 Code: Bad RIP value. RSP: 002b:00007ffcb2568cb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007ffcb2568d70 RCX: 00007f8295b77840 RDX: 0000562437232fe3 RSI: 00000000000a0800 RDI: 0000562437ea5c00 RBP: 00007ffcb2569200 R08: 0000562437232670 R09: 0000000000000010 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffcb2568e60 R13: 0000562437e8b010 R14: 0000562437ea7140 R15: 00007ffcb2568d30 INFO: task syz-executor.0:10025 blocked for more than 140 seconds. Not tainted 4.19.190-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28216 10025 8486 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x21a/0x3e0 kernel/locking/rwsem-xadd.c:309 call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94 __down_read arch/x86/include/asm/rwsem.h:83 [inline] down_read+0x49/0xb0 kernel/locking/rwsem.c:26 __get_super.part.3+0x165/0x210 fs/super.c:698 __get_super include/linux/spinlock.h:329 [inline] get_super+0x23/0x30 fs/super.c:727 fsync_bdev+0x13/0xb0 fs/block_dev.c:483 invalidate_partition+0x1f/0x40 block/genhd.c:1592 drop_partitions block/partition-generic.c:454 [inline] rescan_partitions+0xac/0x8c0 block/partition-generic.c:527 __blkdev_reread_part+0x12a/0x1a0 block/ioctl.c:173 blkdev_reread_part+0x20/0x40 block/ioctl.c:193 loop_reread_partitions+0x16/0x30 drivers/block/loop.c:645 loop_set_status+0xc4a/0x13f0 drivers/block/loop.c:1330 loop_set_status64+0x8b/0xd0 drivers/block/loop.c:1450 lo_ioctl+0x5aa/0x1e40 drivers/block/loop.c:1593 __blkdev_driver_ioctl block/ioctl.c:303 [inline] blkdev_ioctl+0x7ea/0x1790 block/ioctl.c:601 block_ioctl+0xd7/0x130 fs/block_dev.c:1906 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x466217 Code: 3c 1c 48 f7 d8 49 39 c4 72 b8 e8 a4 48 02 00 85 c0 78 bd 48 83 c4 08 4c 89 e0 5b 41 5c c3 0f 1f 44 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f22bb8edef8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f22bb8edf40 RCX: 0000000000466217 RDX: 00007f22bb8ee050 RSI: 0000000000004c04 RDI: 0000000000000004 RBP: 00000000004bf9fb R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00007f22bb8ee050 R13: 00007ffd8309b48f R14: 00007f22bb8ee300 R15: 0000000000022000 INFO: task syz-executor.5:10110 blocked for more than 140 seconds. Not tainted 4.19.190-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28296 10110 8489 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x21a/0x3e0 kernel/locking/rwsem-xadd.c:309 call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94 __down_read arch/x86/include/asm/rwsem.h:83 [inline] down_read+0x49/0xb0 kernel/locking/rwsem.c:26 __get_super.part.3+0x165/0x210 fs/super.c:698 __get_super include/linux/spinlock.h:329 [inline] get_super+0x23/0x30 fs/super.c:727 fsync_bdev+0x13/0xb0 fs/block_dev.c:483 invalidate_partition+0x1f/0x40 block/genhd.c:1592 drop_partitions block/partition-generic.c:454 [inline] rescan_partitions+0xac/0x8c0 block/partition-generic.c:527 __blkdev_reread_part+0x12a/0x1a0 block/ioctl.c:173 blkdev_reread_part+0x20/0x40 block/ioctl.c:193 loop_reread_partitions+0x16/0x30 drivers/block/loop.c:645 loop_set_status+0xc4a/0x13f0 drivers/block/loop.c:1330 loop_set_status64+0x8b/0xd0 drivers/block/loop.c:1450 lo_ioctl+0x5aa/0x1e40 drivers/block/loop.c:1593 __blkdev_driver_ioctl block/ioctl.c:303 [inline] blkdev_ioctl+0x7ea/0x1790 block/ioctl.c:601 block_ioctl+0xd7/0x130 fs/block_dev.c:1906 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x466217 Code: 3c 1c 48 f7 d8 49 39 c4 72 b8 e8 a4 48 02 00 85 c0 78 bd 48 83 c4 08 4c 89 e0 5b 41 5c c3 0f 1f 44 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f91867adef8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f91867adf40 RCX: 0000000000466217 RDX: 00007f91867ae050 RSI: 0000000000004c04 RDI: 0000000000000004 RBP: 00000000004bf9fb R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00007f91867ae050 R13: 00007ffcd3085c2f R14: 00007f91867ae300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/1567: #0: 000000002e1b1b26 (rcu_read_lock){....}, at: debug_show_all_locks+0x5b/0x27a kernel/locking/lockdep.c:4443 1 lock held by systemd-udevd/4699: #0: 000000003a738901 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19a/0x1200 fs/block_dev.c:1478 1 lock held by in:imklog/7799: #0: 00000000928e5b3d (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xa7/0xd0 fs/file.c:767 1 lock held by syz-executor.0/10019: 2 locks held by syz-executor.0/10025: #0: 000000003a738901 (&bdev->bd_mutex){+.+.}, at: blkdev_reread_part+0x18/0x40 block/ioctl.c:192 #1: 000000000dbda43d (&type->s_umount_key#49){.+.+}, at: __get_super.part.3+0x165/0x210 fs/super.c:698 1 lock held by syz-executor.5/10105: 2 locks held by syz-executor.5/10110: #0: 00000000a6cdb427 (&bdev->bd_mutex){+.+.}, at: blkdev_reread_part+0x18/0x40 block/ioctl.c:192 #1: 0000000029ffeeca (&type->s_umount_key#49){.+.+}, at: __get_super.part.3+0x165/0x210 fs/super.c:698 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1567 Comm: khungtaskd Not tainted 4.19.190-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+0x17c/0x226 lib/dump_stack.c:118 nmi_cpu_backtrace.cold.0+0x3c/0x78 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0xf6/0x120 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x5c3/0xb40 kernel/hung_task.c:287 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 10105 Comm: syz-executor.5 Not tainted 4.19.190-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:lookup_bh_lru fs/buffer.c:1261 [inline] RIP: 0010:__find_get_block+0x9f/0xbb0 fs/buffer.c:1291 Code: 00 48 83 3d 02 13 f0 07 00 0f 84 ca 04 00 00 fa 66 0f 1f 44 00 00 49 bc 00 00 00 00 00 fc ff df 45 31 ff e8 93 c7 be ff eb 0e <41> 83 c7 01 41 83 ff 10 0f 84 19 01 00 00 48 c7 c7 a0 fc 13 88 e8 RSP: 0018:ffff888095507ac0 EFLAGS: 00000083 RAX: ffff88808df26738 RBX: ffff88808df26738 RCX: 0000000000000000 RDX: 1ffff11011be4cea RSI: 0000000000000004 RDI: ffff88808df26750 RBP: ffff888095507b10 R08: fffff94000408a0f R09: fffff94000408a0e R10: fffff94000408a0e R11: ffffea0002045077 R12: dffffc0000000000 R13: 0000000000000008 R14: ffff888095e37340 R15: 0000000000000004 FS: 00007f91867cf700(0000) GS:ffff8880ba200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1990bb0000 CR3: 00000000964ec000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __getblk_slow fs/buffer.c:1040 [inline] __getblk_gfp+0x140/0x7b0 fs/buffer.c:1321 __bread_gfp+0xa/0x190 fs/buffer.c:1366 sb_bread include/linux/buffer_head.h:309 [inline] vxfs_try_sb_magic+0x9f/0x370 fs/freevxfs/vxfs_super.c:163 vxfs_fill_super+0x40c/0x790 fs/freevxfs/vxfs_super.c:244 mount_bdev+0x26f/0x330 fs/super.c:1158 vxfs_mount+0x10/0x20 fs/freevxfs/vxfs_super.c:317 mount_fs+0x7f/0x2b0 fs/super.c:1261 vfs_kern_mount.part.11+0x58/0x3d0 fs/namespace.c:961 vfs_kern_mount fs/namespace.c:951 [inline] do_new_mount fs/namespace.c:2469 [inline] do_mount+0x376/0x2710 fs/namespace.c:2799 ksys_mount+0xb1/0xd0 fs/namespace.c:3015 __do_sys_mount fs/namespace.c:3029 [inline] __se_sys_mount fs/namespace.c:3026 [inline] __x64_sys_mount+0xb9/0x150 fs/namespace.c:3026 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x466459 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f91867cf188 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000466459 RDX: 0000000020000340 RSI: 00000000200000c0 RDI: 0000000020000240 RBP: 00000000004bf9fb R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007ffcd3085c2f R14: 00007f91867cf300 R15: 0000000000022000