bisecting fixing commit since 3207316b3beec7e38e5dbe2f463df0cec71e0b97 building syzkaller on 79264ae39c1ef4b4875ab67d6f0c8c3e75aa6a34 testing commit 3207316b3beec7e38e5dbe2f463df0cec71e0b97 with gcc (GCC) 8.4.1 20210217 kernel signature: dd9a1654f90d34ebe1db66277730c11d4480c65637d3f0c371831873e83bb334 all runs: crashed: INFO: task hung in vfs_setxattr testing current HEAD 255b58a2b3af0baa0ee11507390349217b8b73b0 testing commit 255b58a2b3af0baa0ee11507390349217b8b73b0 with gcc (GCC) 8.4.1 20210217 kernel signature: 15604621ed27c0ef234e9217c53aa189fbd95c2df8b6417f490d9f820c04946e all runs: crashed: INFO: task hung in vfs_setxattr revisions tested: 2, total time: 27m18.730566396s (build: 15m9.801359949s, test: 11m13.528585727s) the crash still happens on HEAD commit msg: Linux 4.19.176 crash: INFO: task hung in vfs_setxattr Bluetooth: hci1: command 0x0406 tx timeout Bluetooth: hci3: command 0x0406 tx timeout Bluetooth: hci5: command 0x0406 tx timeout Bluetooth: hci0: command 0x0406 tx timeout Bluetooth: hci2: command 0x0406 tx timeout INFO: task syz-executor.5:9843 blocked for more than 140 seconds. Not tainted 4.19.176-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D29528 9843 8501 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_write_failed_common kernel/locking/rwsem-xadd.c:589 [inline] rwsem_down_write_failed+0x3bb/0x780 kernel/locking/rwsem-xadd.c:618 call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117 __down_write arch/x86/include/asm/rwsem.h:142 [inline] down_write+0x53/0x90 kernel/locking/rwsem.c:72 inode_lock include/linux/fs.h:748 [inline] vfs_setxattr+0xd6/0x280 fs/xattr.c:254 setxattr+0x1af/0x280 fs/xattr.c:520 __do_sys_fsetxattr fs/xattr.c:575 [inline] __se_sys_fsetxattr+0xff/0x160 fs/xattr.c:564 __x64_sys_fsetxattr+0xb9/0x140 fs/xattr.c:564 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465b09 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:00007ff248d0b188 EFLAGS: 00000246 ORIG_RAX: 00000000000000be RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 0000000000465b09 RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000005 RBP: 00000000004b069f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c008 R13: 00007fff0d86626f R14: 00007ff248d0b300 R15: 0000000000022000 INFO: task syz-executor.4:9891 blocked for more than 140 seconds. Not tainted 4.19.176-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D29752 9891 8493 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_write_failed_common kernel/locking/rwsem-xadd.c:589 [inline] rwsem_down_write_failed+0x3bb/0x780 kernel/locking/rwsem-xadd.c:618 call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117 __down_write arch/x86/include/asm/rwsem.h:142 [inline] down_write+0x53/0x90 kernel/locking/rwsem.c:72 inode_lock include/linux/fs.h:748 [inline] vfs_setxattr+0xd6/0x280 fs/xattr.c:254 setxattr+0x1af/0x280 fs/xattr.c:520 __do_sys_fsetxattr fs/xattr.c:575 [inline] __se_sys_fsetxattr+0xff/0x160 fs/xattr.c:564 __x64_sys_fsetxattr+0xb9/0x140 fs/xattr.c:564 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465b09 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:00007f431ba28188 EFLAGS: 00000246 ORIG_RAX: 00000000000000be RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 0000000000465b09 RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000005 RBP: 00000000004b069f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c008 R13: 00007ffc6e98b66f R14: 00007f431ba28300 R15: 0000000000022000 INFO: task syz-executor.3:9927 blocked for more than 140 seconds. Not tainted 4.19.176-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D29752 9927 8491 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_write_failed_common kernel/locking/rwsem-xadd.c:589 [inline] rwsem_down_write_failed+0x3bb/0x780 kernel/locking/rwsem-xadd.c:618 call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117 __down_write arch/x86/include/asm/rwsem.h:142 [inline] down_write+0x53/0x90 kernel/locking/rwsem.c:72 inode_lock include/linux/fs.h:748 [inline] vfs_setxattr+0xd6/0x280 fs/xattr.c:254 setxattr+0x1af/0x280 fs/xattr.c:520 __do_sys_fsetxattr fs/xattr.c:575 [inline] __se_sys_fsetxattr+0xff/0x160 fs/xattr.c:564 __x64_sys_fsetxattr+0xb9/0x140 fs/xattr.c:564 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465b09 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:00007f602d0ca188 EFLAGS: 00000246 ORIG_RAX: 00000000000000be RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 0000000000465b09 RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000005 RBP: 00000000004b069f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c008 R13: 00007ffd605298df R14: 00007f602d0ca300 R15: 0000000000022000 INFO: task syz-executor.0:9983 blocked for more than 140 seconds. Not tainted 4.19.176-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D29752 9983 8500 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_write_failed_common kernel/locking/rwsem-xadd.c:589 [inline] rwsem_down_write_failed+0x3bb/0x780 kernel/locking/rwsem-xadd.c:618 call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117 __down_write arch/x86/include/asm/rwsem.h:142 [inline] down_write+0x53/0x90 kernel/locking/rwsem.c:72 inode_lock include/linux/fs.h:748 [inline] vfs_setxattr+0xd6/0x280 fs/xattr.c:254 setxattr+0x1af/0x280 fs/xattr.c:520 __do_sys_fsetxattr fs/xattr.c:575 [inline] __se_sys_fsetxattr+0xff/0x160 fs/xattr.c:564 __x64_sys_fsetxattr+0xb9/0x140 fs/xattr.c:564 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465b09 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:00007fd33209e188 EFLAGS: 00000246 ORIG_RAX: 00000000000000be RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 0000000000465b09 RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000005 RBP: 00000000004b069f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c008 R13: 00007fff1fde3d3f R14: 00007fd33209e300 R15: 0000000000022000 INFO: task syz-executor.2:10014 blocked for more than 140 seconds. Not tainted 4.19.176-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D29752 10014 8495 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_write_failed_common kernel/locking/rwsem-xadd.c:589 [inline] rwsem_down_write_failed+0x3bb/0x780 kernel/locking/rwsem-xadd.c:618 call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117 __down_write arch/x86/include/asm/rwsem.h:142 [inline] down_write+0x53/0x90 kernel/locking/rwsem.c:72 inode_lock include/linux/fs.h:748 [inline] vfs_setxattr+0xd6/0x280 fs/xattr.c:254 setxattr+0x1af/0x280 fs/xattr.c:520 __do_sys_fsetxattr fs/xattr.c:575 [inline] __se_sys_fsetxattr+0xff/0x160 fs/xattr.c:564 __x64_sys_fsetxattr+0xb9/0x140 fs/xattr.c:564 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465b09 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:00007fda9d662188 EFLAGS: 00000246 ORIG_RAX: 00000000000000be RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 0000000000465b09 RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000005 RBP: 00000000004b069f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c008 R13: 00007ffd1e1003cf R14: 00007fda9d662300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/1566: #0: 000000001779d3ad (rcu_read_lock){....}, at: debug_show_all_locks+0x5b/0x27a kernel/locking/lockdep.c:4442 1 lock held by kswapd0/1966: 1 lock held by kswapd1/1967: 1 lock held by in:imklog/7804: #0: 00000000ecb1002b (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xa7/0xd0 fs/file.c:767 1 lock held by syz-executor.5/9837: 3 locks held by syz-executor.4/9873: 2 locks held by syz-executor.4/9891: #0: 00000000e1c0893a (sb_writers#14){.+.+}, at: sb_start_write include/linux/fs.h:1579 [inline] #0: 00000000e1c0893a (sb_writers#14){.+.+}, at: mnt_want_write_file+0x67/0x110 fs/namespace.c:418 #1: 00000000bac7d632 (&type->i_mutex_dir_key#9){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] #1: 00000000bac7d632 (&type->i_mutex_dir_key#9){+.+.}, at: vfs_setxattr+0xd6/0x280 fs/xattr.c:254 1 lock held by syz-executor.3/9911: 1 lock held by syz-executor.0/9967: #0: 000000009e367d36 (rcu_preempt_state.exp_mutex){+.+.}, at: exp_funnel_lock kernel/rcu/tree_exp.h:297 [inline] #0: 000000009e367d36 (rcu_preempt_state.exp_mutex){+.+.}, at: _synchronize_rcu_expedited+0x3a0/0x8a0 kernel/rcu/tree_exp.h:667 4 locks held by syz-executor.2/10005: 2 locks held by syz-executor.2/10014: #0: 00000000d99618d6 (sb_writers#14){.+.+}, at: sb_start_write include/linux/fs.h:1579 [inline] #0: 00000000d99618d6 (sb_writers#14){.+.+}, at: mnt_want_write_file+0x67/0x110 fs/namespace.c:418 #1: 000000007f8c1963 (&type->i_mutex_dir_key#9){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] #1: 000000007f8c1963 (&type->i_mutex_dir_key#9){+.+.}, at: vfs_setxattr+0xd6/0x280 fs/xattr.c:254 2 locks held by syz-executor.1/10006: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1566 Comm: khungtaskd Not tainted 4.19.176-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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4682 Comm: systemd-journal Not tainted 4.19.176-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:do_syscall_64+0x2c1/0x4e0 arch/x86/entry/common.c:297 Code: fc ff df 48 89 fa 48 c1 ea 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e 67 01 00 00 83 63 08 f9 0f 1f 44 00 00 0f 00 2d df e0 ff 06 <48> 83 c4 08 5b 41 5c 41 5d 41 5e 5d c3 65 4c 8b 2c 25 80 df 01 00 RSP: 0018:ffff8880a19a7f20 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff8880a199a1c0 RCX: 0000000000000001 RDX: 1ffff11014333439 RSI: 0000000000000100 RDI: ffff8880a199a1c8 RBP: ffff8880a19a7f48 R08: 0000000000000000 R09: ffffed1017464552 R10: ffffed1017464552 R11: ffff8880ba322a93 R12: ffff8880a19a7f58 R13: ffff8880a199a1c0 R14: ffff8880a199a1c0 R15: 0000000000000000 FS: 00007f25f067e8c0(0000) GS:ffff8880ba300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f25edac0010 CR3: 00000000a1a4e000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f25ef917f17 Code: ff ff ff 48 8b 4d a0 0f b7 51 fe 48 8b 4d a8 66 89 54 08 fe e9 1a ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 b8 27 00 00 00 0f 05 0f 1f 84 00 00 00 00 00 b8 6e 00 00 00 0f 05 c3 0f 1f 84 00 00 RSP: 002b:00007ffea19876e8 EFLAGS: 00000202 ORIG_RAX: 0000000000000027 RAX: 000000000000124a RBX: 0000562a4b6991e0 RCX: 00007f25ef917f17 RDX: 0000000000000000 RSI: 000000000d088dc8 RDI: 0000562a4b6991e0 RBP: 000000000000124a R08: 00007ffea19f2000 R09: 0000003b3b0d3bcf R10: 0013cce4a4726e05 R11: 0000000000000202 R12: ffffffffffffffff R13: 00007ffea1987798 R14: 0000562a49bec958 R15: 0005bbb6ef216c53