bisecting fixing commit since b850307b279cbd12ab8c654d1a3dfe55319cc475 building syzkaller on d88894e6773ab63ac8b3f4b2edbae88290aaf0d6 testing commit b850307b279cbd12ab8c654d1a3dfe55319cc475 with gcc (GCC) 8.1.0 kernel signature: c5cb1298b24197556ebec3228aa5eed486d1c65e8997290adc35012b98ab7664 all runs: crashed: INFO: task hung in __get_super testing current HEAD 47cbf4cc32db62f053c4cd04fc6ee39a0218139e testing commit 47cbf4cc32db62f053c4cd04fc6ee39a0218139e with gcc (GCC) 8.1.0 kernel signature: 91c0800087a4fe21acee5decb73d19aa4481b6314057a05dd5cb1feeb3864ad5 all runs: crashed: INFO: task hung in __get_super revisions tested: 2, total time: 33m45.624576646s (build: 19m23.680434105s, test: 13m33.121492549s) the crash still happens on HEAD commit msg: Linux 4.14.211 crash: INFO: task hung in __get_super IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready random: crng init done random: 7 urandom warning(s) missed due to ratelimiting INFO: task syz-executor.2:7114 blocked for more than 140 seconds. Not tainted 4.14.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28696 7114 5830 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x1fb/0x390 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:66 [inline] down_read+0x49/0xb0 kernel/locking/rwsem.c:26 __get_super.part.2+0x198/0x260 fs/super.c:678 __get_super include/linux/spinlock.h:317 [inline] get_super+0x23/0x30 fs/super.c:707 fsync_bdev+0x13/0xb0 fs/block_dev.c:495 invalidate_partition+0x1f/0x40 block/genhd.c:1506 drop_partitions block/partition-generic.c:442 [inline] rescan_partitions+0xac/0x8c0 block/partition-generic.c:515 __blkdev_reread_part+0x12a/0x190 block/ioctl.c:173 blkdev_reread_part+0x20/0x40 block/ioctl.c:193 loop_reread_partitions+0x5d/0x70 drivers/block/loop.c:624 loop_set_status+0xb04/0x1070 drivers/block/loop.c:1193 loop_set_status64+0x83/0xc0 drivers/block/loop.c:1311 lo_ioctl+0x53e/0x1c20 drivers/block/loop.c:1441 __blkdev_driver_ioctl block/ioctl.c:297 [inline] blkdev_ioctl+0x7c0/0x1760 block/ioctl.c:594 block_ioctl+0xd7/0x130 fs/block_dev.c:1893 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x180/0xfb0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x74/0x80 fs/ioctl.c:692 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45c0a7 RSP: 002b:00007fd72a5769f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fd72a5776d4 RCX: 000000000045c0a7 RDX: 00007fd72a576ab0 RSI: 0000000000004c04 RDI: 0000000000000004 RBP: 0000000000000003 R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000003 R13: 00007ffcb9b8f27f R14: 0000000000000004 R15: 000000000078bf0c INFO: task syz-executor.2:7121 blocked for more than 140 seconds. Not tainted 4.14.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28000 7121 5830 0x80000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 lo_ioctl+0x8a/0x1c20 drivers/block/loop.c:1414 __blkdev_driver_ioctl block/ioctl.c:297 [inline] blkdev_ioctl+0x7c0/0x1760 block/ioctl.c:594 ioctl_by_bdev+0x95/0x110 fs/block_dev.c:2078 isofs_get_last_session fs/isofs/inode.c:571 [inline] isofs_fill_super+0x187b/0x2690 fs/isofs/inode.c:670 mount_bdev+0x26f/0x330 fs/super.c:1134 isofs_mount+0x10/0x20 fs/isofs/inode.c:1570 mount_fs+0x7f/0x269 fs/super.c:1237 vfs_kern_mount.part.9+0x58/0x3c0 fs/namespace.c:1046 vfs_kern_mount fs/namespace.c:1036 [inline] do_new_mount fs/namespace.c:2549 [inline] do_mount+0x352/0x2af0 fs/namespace.c:2879 SYSC_mount fs/namespace.c:3095 [inline] SyS_mount+0xb1/0xd0 fs/namespace.c:3072 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45c1d9 RSP: 002b:00007fd72a555c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 000000000001fa40 RCX: 000000000045c1d9 RDX: 0000000020000080 RSI: 0000000020000200 RDI: 0000000020000340 RBP: 000000000078bff0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bfac R13: 00007ffcb9b8f27f R14: 00007fd72a5569c0 R15: 000000000078bfac INFO: task syz-executor.2:7167 blocked for more than 140 seconds. Not tainted 4.14.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28904 7167 5830 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 blkdev_get+0x265/0x890 fs/block_dev.c:1611 blkdev_open+0x19f/0x200 fs/block_dev.c:1772 do_dentry_open+0x3e4/0xde0 fs/open.c:777 vfs_open+0xfc/0x240 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0xb73/0x27a0 fs/namei.c:3569 do_filp_open+0x16b/0x220 fs/namei.c:3603 do_sys_open+0x1c2/0x340 fs/open.c:1081 SYSC_open fs/open.c:1099 [inline] SyS_open+0x19/0x20 fs/open.c:1094 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x415f51 RSP: 002b:00007fd72a5349f0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007fd72a5356d4 RCX: 0000000000415f51 RDX: 00007fd72a534baa RSI: 0000000000000002 RDI: 00007fd72a534ba0 RBP: 0000000000000003 R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000293 R12: 0000000000000003 R13: 00007ffcb9b8f27f R14: 00007fd72a5359c0 R15: 000000000078c04c INFO: task syz-executor.2:7168 blocked for more than 140 seconds. Not tainted 4.14.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D29384 7168 5830 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 blkdev_get+0x417/0x890 fs/block_dev.c:1611 blkdev_get_by_path+0x71/0xb0 fs/block_dev.c:1692 mount_bdev+0x43/0x330 fs/super.c:1092 isofs_mount+0x10/0x20 fs/isofs/inode.c:1570 mount_fs+0x7f/0x269 fs/super.c:1237 vfs_kern_mount.part.9+0x58/0x3c0 fs/namespace.c:1046 vfs_kern_mount fs/namespace.c:1036 [inline] do_new_mount fs/namespace.c:2549 [inline] do_mount+0x352/0x2af0 fs/namespace.c:2879 SYSC_mount fs/namespace.c:3095 [inline] SyS_mount+0xb1/0xd0 fs/namespace.c:3072 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45c1d9 RSP: 002b:00007fd72a513c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 000000000001fa40 RCX: 000000000045c1d9 RDX: 0000000020000080 RSI: 0000000020000200 RDI: 0000000020000340 RBP: 000000000078c130 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078c0ec R13: 00007ffcb9b8f27f R14: 00007fd72a5149c0 R15: 000000000078c0ec INFO: task systemd-udevd:7118 blocked for more than 140 seconds. Not tainted 4.14.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. systemd-udevd D28120 7118 3334 0x00000124 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 blkdev_get+0x265/0x890 fs/block_dev.c:1611 blkdev_open+0x19f/0x200 fs/block_dev.c:1772 do_dentry_open+0x3e4/0xde0 fs/open.c:777 vfs_open+0xfc/0x240 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0xb73/0x27a0 fs/namei.c:3569 do_filp_open+0x16b/0x220 fs/namei.c:3603 do_sys_open+0x1c2/0x340 fs/open.c:1081 SYSC_open fs/open.c:1099 [inline] SyS_open+0x19/0x20 fs/open.c:1094 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f57d943a840 RSP: 002b:00007fff4fdac348 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00005599a3e22700 RCX: 00007f57d943a840 RDX: 00005599a23a3fe3 RSI: 0000000000080000 RDI: 00005599a3e29420 RBP: 0000000000000001 R08: 00005599a23a3670 R09: 0000000000000110 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00005599a3e29300 R15: 00000000ffffffff INFO: task systemd-udevd:7163 blocked for more than 140 seconds. Not tainted 4.14.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. systemd-udevd D28184 7163 3334 0x00000124 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 blkdev_get+0x265/0x890 fs/block_dev.c:1611 blkdev_open+0x19f/0x200 fs/block_dev.c:1772 do_dentry_open+0x3e4/0xde0 fs/open.c:777 vfs_open+0xfc/0x240 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0xb73/0x27a0 fs/namei.c:3569 do_filp_open+0x16b/0x220 fs/namei.c:3603 do_sys_open+0x1c2/0x340 fs/open.c:1081 SYSC_open fs/open.c:1099 [inline] SyS_open+0x19/0x20 fs/open.c:1094 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f57d943a840 RSP: 002b:00007fff4fdb1178 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00005599a3e287f0 RCX: 00007f57d943a840 RDX: 00005599a23a3fe3 RSI: 00000000000a0800 RDI: 00005599a3e23220 RBP: 00007fff4fdb12f0 R08: 00005599a23a3670 R09: 0000000000000010 R10: 00005599a23a3d0c R11: 0000000000000246 R12: 00007fff4fdb1240 R13: 00005599a3e29db0 R14: 0000000000000003 R15: 000000000000000e INFO: task syz-executor.3:7165 blocked for more than 140 seconds. Not tainted 4.14.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28080 7165 5831 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x1fb/0x390 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:66 [inline] down_read+0x49/0xb0 kernel/locking/rwsem.c:26 __get_super.part.2+0x198/0x260 fs/super.c:678 __get_super include/linux/spinlock.h:317 [inline] get_super+0x23/0x30 fs/super.c:707 fsync_bdev+0x13/0xb0 fs/block_dev.c:495 invalidate_partition+0x1f/0x40 block/genhd.c:1506 drop_partitions block/partition-generic.c:442 [inline] rescan_partitions+0xac/0x8c0 block/partition-generic.c:515 __blkdev_reread_part+0x12a/0x190 block/ioctl.c:173 blkdev_reread_part+0x20/0x40 block/ioctl.c:193 loop_reread_partitions+0x5d/0x70 drivers/block/loop.c:624 loop_clr_fd+0x7ff/0xab0 drivers/block/loop.c:1078 lo_ioctl+0x7da/0x1c20 drivers/block/loop.c:1424 __blkdev_driver_ioctl block/ioctl.c:297 [inline] blkdev_ioctl+0x7c0/0x1760 block/ioctl.c:594 block_ioctl+0xd7/0x130 fs/block_dev.c:1893 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x180/0xfb0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x74/0x80 fs/ioctl.c:692 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45c0a7 RSP: 002b:00007f9ba6d799f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f9ba6d7a6d4 RCX: 000000000045c0a7 RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000004 RBP: 0000000000000003 R08: 0000000000000000 R09: 000000000000000c R10: 0000000000000064 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000004 R15: 000000000078bf0c INFO: task syz-executor.3:7174 blocked for more than 140 seconds. Not tainted 4.14.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28952 7174 5831 0x80000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 lo_ioctl+0x8a/0x1c20 drivers/block/loop.c:1414 __blkdev_driver_ioctl block/ioctl.c:297 [inline] blkdev_ioctl+0x7c0/0x1760 block/ioctl.c:594 ioctl_by_bdev+0x95/0x110 fs/block_dev.c:2078 isofs_get_last_session fs/isofs/inode.c:571 [inline] isofs_fill_super+0x187b/0x2690 fs/isofs/inode.c:670 mount_bdev+0x26f/0x330 fs/super.c:1134 isofs_mount+0x10/0x20 fs/isofs/inode.c:1570 mount_fs+0x7f/0x269 fs/super.c:1237 vfs_kern_mount.part.9+0x58/0x3c0 fs/namespace.c:1046 vfs_kern_mount fs/namespace.c:1036 [inline] do_new_mount fs/namespace.c:2549 [inline] do_mount+0x352/0x2af0 fs/namespace.c:2879 SYSC_mount fs/namespace.c:3095 [inline] SyS_mount+0xb1/0xd0 fs/namespace.c:3072 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45c1d9 RSP: 002b:00007f9ba6d58c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 000000000001fa40 RCX: 000000000045c1d9 RDX: 0000000020000080 RSI: 0000000020000200 RDI: 0000000020000340 RBP: 000000000078bff0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bfac R13: 00007ffe0ec0247f R14: 00007f9ba6d599c0 R15: 000000000078bfac INFO: task syz-executor.3:7239 blocked for more than 140 seconds. Not tainted 4.14.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28904 7239 5831 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 blkdev_get+0x265/0x890 fs/block_dev.c:1611 blkdev_open+0x19f/0x200 fs/block_dev.c:1772 do_dentry_open+0x3e4/0xde0 fs/open.c:777 vfs_open+0xfc/0x240 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0xb73/0x27a0 fs/namei.c:3569 do_filp_open+0x16b/0x220 fs/namei.c:3603 do_sys_open+0x1c2/0x340 fs/open.c:1081 SYSC_open fs/open.c:1099 [inline] SyS_open+0x19/0x20 fs/open.c:1094 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x415f51 RSP: 002b:00007f9ba6d379f0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007f9ba6d386d4 RCX: 0000000000415f51 RDX: 00007f9ba6d37baa RSI: 0000000000000002 RDI: 00007f9ba6d37ba0 RBP: 0000000000000003 R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000293 R12: 0000000000000003 R13: 00007ffe0ec0247f R14: 00007f9ba6d389c0 R15: 000000000078c04c INFO: task syz-executor.3:7240 blocked for more than 140 seconds. Not tainted 4.14.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D29384 7240 5831 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 blkdev_get+0x417/0x890 fs/block_dev.c:1611 blkdev_get_by_path+0x71/0xb0 fs/block_dev.c:1692 mount_bdev+0x43/0x330 fs/super.c:1092 isofs_mount+0x10/0x20 fs/isofs/inode.c:1570 mount_fs+0x7f/0x269 fs/super.c:1237 vfs_kern_mount.part.9+0x58/0x3c0 fs/namespace.c:1046 vfs_kern_mount fs/namespace.c:1036 [inline] do_new_mount fs/namespace.c:2549 [inline] do_mount+0x352/0x2af0 fs/namespace.c:2879 SYSC_mount fs/namespace.c:3095 [inline] SyS_mount+0xb1/0xd0 fs/namespace.c:3072 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45c1d9 RSP: 002b:00007f9ba6d16c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 000000000001fa40 RCX: 000000000045c1d9 RDX: 0000000020000080 RSI: 0000000020000200 RDI: 0000000020000340 RBP: 000000000078c130 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078c0ec R13: 00007ffe0ec0247f R14: 00007f9ba6d179c0 R15: 000000000078c0ec Showing all locks held in the system: 1 lock held by khungtaskd/1059: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4548 3 locks held by syz-executor.2/7114: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8a/0x1c20 drivers/block/loop.c:1414 #1: (&bdev->bd_mutex){+.+.}, at: [] blkdev_reread_part+0x18/0x40 block/ioctl.c:192 #2: (&type->s_umount_key#48){.+.+}, at: [] __get_super.part.2+0x198/0x260 fs/super.c:678 2 locks held by syz-executor.2/7121: #0: (&type->s_umount_key#47/1){+.+.}, at: [] alloc_super fs/super.c:251 [inline] #0: (&type->s_umount_key#47/1){+.+.}, at: [] sget_userns+0x429/0xb40 fs/super.c:516 #1: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8a/0x1c20 drivers/block/loop.c:1414 1 lock held by syz-executor.2/7167: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.2/7168: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by systemd-udevd/7118: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by systemd-udevd/7163: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 3 locks held by syz-executor.3/7165: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8a/0x1c20 drivers/block/loop.c:1414 #1: (&bdev->bd_mutex){+.+.}, at: [] blkdev_reread_part+0x18/0x40 block/ioctl.c:192 #2: (&type->s_umount_key#48){.+.+}, at: [] __get_super.part.2+0x198/0x260 fs/super.c:678 2 locks held by syz-executor.3/7174: #0: (&type->s_umount_key#47/1){+.+.}, at: [] alloc_super fs/super.c:251 [inline] #0: (&type->s_umount_key#47/1){+.+.}, at: [] sget_userns+0x429/0xb40 fs/super.c:516 #1: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8a/0x1c20 drivers/block/loop.c:1414 1 lock held by syz-executor.3/7239: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.3/7240: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 3 locks held by syz-executor.1/7204: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8a/0x1c20 drivers/block/loop.c:1414 #1: (&bdev->bd_mutex){+.+.}, at: [] blkdev_reread_part+0x18/0x40 block/ioctl.c:192 #2: (&type->s_umount_key#48){.+.+}, at: [] __get_super.part.2+0x198/0x260 fs/super.c:678 2 locks held by syz-executor.1/7213: #0: (&type->s_umount_key#47/1){+.+.}, at: [] alloc_super fs/super.c:251 [inline] #0: (&type->s_umount_key#47/1){+.+.}, at: [] sget_userns+0x429/0xb40 fs/super.c:516 #1: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8a/0x1c20 drivers/block/loop.c:1414 1 lock held by syz-executor.1/7250: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.1/7251: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by systemd-udevd/7205: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 3 locks held by syz-executor.0/7243: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8a/0x1c20 drivers/block/loop.c:1414 #1: (&bdev->bd_mutex){+.+.}, at: [] blkdev_reread_part+0x18/0x40 block/ioctl.c:192 #2: (&type->s_umount_key#48){.+.+}, at: [] __get_super.part.2+0x198/0x260 fs/super.c:678 2 locks held by syz-executor.0/7246: #0: (&type->s_umount_key#47/1){+.+.}, at: [] alloc_super fs/super.c:251 [inline] #0: (&type->s_umount_key#47/1){+.+.}, at: [] sget_userns+0x429/0xb40 fs/super.c:516 #1: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8a/0x1c20 drivers/block/loop.c:1414 1 lock held by syz-executor.0/7254: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.0/7255: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by systemd-udevd/7242: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 3 locks held by syz-executor.4/7257: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8a/0x1c20 drivers/block/loop.c:1414 #1: (&bdev->bd_mutex){+.+.}, at: [] blkdev_reread_part+0x18/0x40 block/ioctl.c:192 #2: (&type->s_umount_key#48){.+.+}, at: [] __get_super.part.2+0x198/0x260 fs/super.c:678 2 locks held by syz-executor.4/7262: #0: (&type->s_umount_key#47/1){+.+.}, at: [] alloc_super fs/super.c:251 [inline] #0: (&type->s_umount_key#47/1){+.+.}, at: [] sget_userns+0x429/0xb40 fs/super.c:516 #1: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8a/0x1c20 drivers/block/loop.c:1414 1 lock held by syz-executor.4/7272: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.4/7273: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by systemd-udevd/7261: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 3 locks held by syz-executor.5/7265: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8a/0x1c20 drivers/block/loop.c:1414 #1: (&bdev->bd_mutex){+.+.}, at: [] blkdev_reread_part+0x18/0x40 block/ioctl.c:192 #2: (&type->s_umount_key#48){.+.+}, at: [] __get_super.part.2+0x198/0x260 fs/super.c:678 2 locks held by syz-executor.5/7270: #0: (&type->s_umount_key#47/1){+.+.}, at: [] alloc_super fs/super.c:251 [inline] #0: (&type->s_umount_key#47/1){+.+.}, at: [] sget_userns+0x429/0xb40 fs/super.c:516 #1: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8a/0x1c20 drivers/block/loop.c:1414 1 lock held by syz-executor.5/7274: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.5/7275: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by systemd-udevd/7269: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1059 Comm: khungtaskd Not tainted 4.14.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x14b/0x1f1 lib/dump_stack.c:58 nmi_cpu_backtrace.cold.0+0x3c/0x78 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0xf5/0x119 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:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x51b/0xa70 kernel/hung_task.c:274 kthread+0x338/0x400 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3329 Comm: systemd-journal Not tainted 4.14.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8881e18ba680 task.stack: ffff8881e18c0000 RIP: 0010:rcu_lockdep_current_cpu_online+0x8f/0x140 kernel/rcu/tree.c:1188 RSP: 0018:ffff8881e18c7d70 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ffff8881f672c580 RCX: 1ffffffff0f74dad RDX: 1ffff1103ece58b4 RSI: ffffffff87040400 RDI: ffff8881f672c5a0 RBP: ffff8881e18c7d90 R08: 000000000000000a R09: ffff8881e18c7b40 R10: 00000000fc5c3ad4 R11: 00000000a642648b R12: ffff8881d59aa400 R13: ffff8881f612c380 R14: 00000000014000c0 R15: ffffffff813cd595 FS: 00007f4deba5e8c0(0000) GS:ffff8881f6700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4de8e6a000 CR3: 00000001e236c005 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock_sched_held+0x96/0x120 kernel/rcu/update.c:113 trace_kmem_cache_alloc include/trace/events/kmem.h:54 [inline] kmem_cache_alloc+0x367/0x3e0 mm/slab.c:3553 prepare_creds+0x35/0x350 kernel/cred.c:255 SYSC_faccessat fs/open.c:365 [inline] SyS_faccessat+0x95/0x630 fs/open.c:353 SYSC_access fs/open.c:450 [inline] SyS_access+0x13/0x20 fs/open.c:448 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f4dead1a9c7 RSP: 002b:00007ffe198d29a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007ffe198d59d0 RCX: 00007f4dead1a9c7 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00005577c49039a3 RBP: 00007ffe198d2af0 R08: 00005577c48f93e5 R09: 0000000000000018 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00005577c60448a0 R15: 00007ffe198d2fe0 Code: a3 00 00 00 48 03 1c c5 60 6d ba 87 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 20 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 8e 00 00 00 <48> 8d 7b 28 4c 8b 63 20 48 b8 00 00 00 00 00 fc ff df 48 89 fa