bisecting fixing commit since e23d55af0e1fca9be5c99f0c37d48b289f4d6489 building syzkaller on be2c130d4c0c511da96ce278486cf0564aeadcea testing commit e23d55af0e1fca9be5c99f0c37d48b289f4d6489 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: d9ae992aae1bdcf948f839b8985412f9a6b4f098632ffdb6f78183b5e2ac3a15 run #0: crashed: INFO: task hung in fuse_flush run #1: crashed: INFO: task hung in fuse_flush run #2: crashed: INFO: task hung in fuse_flush run #3: crashed: INFO: task hung in fuse_flush run #4: crashed: INFO: task hung in fuse_launder_page run #5: crashed: INFO: task hung in fuse_flush run #6: crashed: INFO: task hung in fuse_flush run #7: crashed: INFO: task hung in fuse_flush run #8: crashed: INFO: task hung in fuse_flush run #9: crashed: INFO: task hung in fuse_flush run #10: crashed: INFO: task hung in fuse_flush run #11: crashed: INFO: task hung in fuse_flush run #12: crashed: INFO: task hung in fuse_flush run #13: crashed: INFO: task hung in fuse_flush run #14: crashed: INFO: task hung in fuse_flush run #15: crashed: INFO: task hung in fuse_flush run #16: crashed: INFO: task hung in fuse_flush run #17: crashed: INFO: task hung in fuse_flush run #18: crashed: INFO: task hung in fuse_flush run #19: crashed: INFO: task hung in fuse_flush testing current HEAD c2276d585654e8d573366c29c565043ec36adf63 testing commit c2276d585654e8d573366c29c565043ec36adf63 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: ecae2bc543d17c544acf8630dd5f1d9a1dab2ac60e66f550f24316661af16a64 run #0: crashed: INFO: task hung in fuse_flush run #1: crashed: INFO: task hung in fuse_flush run #2: crashed: INFO: task hung in fuse_launder_page run #3: crashed: INFO: task hung in fuse_flush run #4: crashed: INFO: task hung in fuse_flush run #5: crashed: INFO: task hung in fuse_flush run #6: crashed: INFO: task hung in fuse_flush run #7: crashed: INFO: task hung in fuse_flush run #8: crashed: INFO: task hung in fuse_flush run #9: crashed: INFO: task hung in fuse_flush revisions tested: 2, total time: 30m45.454060713s (build: 18m12.675196936s, test: 12m1.644263977s) the crash still happens on HEAD commit msg: Linux 4.19.208 crash: INFO: task hung in fuse_flush Bluetooth: hci5: command 0x0406 tx timeout Bluetooth: hci3: command 0x0406 tx timeout Bluetooth: hci2: command 0x0406 tx timeout ieee802154 phy0 wpan0: encryption failed: -22 ieee802154 phy1 wpan1: encryption failed: -22 INFO: task syz-executor.1:9836 blocked for more than 140 seconds. Not tainted 4.19.208-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D28232 9836 8447 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] fuse_flush+0x1a2/0x600 fs/fuse/file.c:421 filp_close+0x9a/0x120 fs/open.c:1162 __close_fd+0x100/0x1a0 fs/file.c:636 __do_sys_close fs/open.c:1181 [inline] __se_sys_close+0x3f/0x80 fs/open.c:1179 __x64_sys_close+0x2c/0x40 fs/open.c:1179 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x41940b Code: Bad RIP value. RSP: 002b:00007ffe7b9c0750 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000041940b RDX: 0000000000579ab0 RSI: 00000000000f4240 RDI: 0000000000000004 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000579908 R10: 0001c9ec549ee05c R11: 0000000000000293 R12: 000000000000c359 R13: 00000000000003e8 R14: 000000000056bf80 R15: 000000000000c2c2 INFO: task syz-executor.1:9888 blocked for more than 140 seconds. Not tainted 4.19.208-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D27864 9888 8447 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 fuse_wait_on_page_writeback fs/fuse/file.c:383 [inline] fuse_wait_on_page_writeback+0xee/0x130 fs/fuse/file.c:379 fuse_launder_page fs/fuse/file.c:2033 [inline] fuse_launder_page+0x92/0xc0 fs/fuse/file.c:2026 do_launder_page mm/truncate.c:655 [inline] invalidate_inode_pages2_range+0x686/0xdb0 mm/truncate.c:725 invalidate_inode_pages2+0x12/0x20 mm/truncate.c:766 fuse_finish_open+0x234/0x4d0 fs/fuse/file.c:182 fuse_open_common+0x1e4/0x240 fs/fuse/file.c:222 fuse_open+0xb/0x10 fs/fuse/file.c:286 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 ksys_open include/linux/syscalls.h:1276 [inline] __do_sys_creat fs/open.c:1143 [inline] __se_sys_creat fs/open.c:1141 [inline] __x64_sys_creat+0x5c/0x80 fs/open.c:1141 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4665f9 Code: Bad RIP value. RSP: 002b:00007f32f0621188 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 000000000056c260 RCX: 00000000004665f9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000280 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c260 R13: 00007ffe7b9c06ef R14: 00007f32f0621300 R15: 0000000000022000 INFO: task syz-executor.4:9902 blocked for more than 140 seconds. Not tainted 4.19.208-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28232 9902 8454 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] fuse_flush+0x1a2/0x600 fs/fuse/file.c:421 filp_close+0x9a/0x120 fs/open.c:1162 __close_fd+0x100/0x1a0 fs/file.c:636 __do_sys_close fs/open.c:1181 [inline] __se_sys_close+0x3f/0x80 fs/open.c:1179 __x64_sys_close+0x2c/0x40 fs/open.c:1179 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x41940b Code: Bad RIP value. RSP: 002b:00007fff11dfdc00 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000041940b RDX: 0000000000579ab0 RSI: 00000000000f4240 RDI: 0000000000000004 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000579908 R10: 00085f7a80437f7c R11: 0000000000000293 R12: 000000000000c435 R13: 00000000000003e8 R14: 000000000056bf80 R15: 000000000000c380 INFO: task syz-executor.4:9944 blocked for more than 140 seconds. Not tainted 4.19.208-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28184 9944 8454 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 fuse_wait_on_page_writeback fs/fuse/file.c:383 [inline] fuse_wait_on_page_writeback+0xee/0x130 fs/fuse/file.c:379 fuse_launder_page fs/fuse/file.c:2033 [inline] fuse_launder_page+0x92/0xc0 fs/fuse/file.c:2026 do_launder_page mm/truncate.c:655 [inline] invalidate_inode_pages2_range+0x686/0xdb0 mm/truncate.c:725 invalidate_inode_pages2+0x12/0x20 mm/truncate.c:766 fuse_finish_open+0x234/0x4d0 fs/fuse/file.c:182 fuse_open_common+0x1e4/0x240 fs/fuse/file.c:222 fuse_open+0xb/0x10 fs/fuse/file.c:286 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 ksys_open include/linux/syscalls.h:1276 [inline] __do_sys_creat fs/open.c:1143 [inline] __se_sys_creat fs/open.c:1141 [inline] __x64_sys_creat+0x5c/0x80 fs/open.c:1141 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4665f9 Code: Bad RIP value. RSP: 002b:00007feb5a97b188 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 000000000056c260 RCX: 00000000004665f9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000280 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c260 R13: 00007fff11dfdb9f R14: 00007feb5a97b300 R15: 0000000000022000 INFO: task syz-executor.3:10011 blocked for more than 140 seconds. Not tainted 4.19.208-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28232 10011 8445 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] fuse_flush+0x1a2/0x600 fs/fuse/file.c:421 filp_close+0x9a/0x120 fs/open.c:1162 __close_fd+0x100/0x1a0 fs/file.c:636 __do_sys_close fs/open.c:1181 [inline] __se_sys_close+0x3f/0x80 fs/open.c:1179 __x64_sys_close+0x2c/0x40 fs/open.c:1179 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x41940b Code: Bad RIP value. RSP: 002b:00007ffdbce195e0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000041940b RDX: 0000000000579ab0 RSI: 00000000000f4240 RDI: 0000000000000004 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000579908 R10: 000478b81c4c5858 R11: 0000000000000293 R12: 000000000000cf6b R13: 00000000000003e8 R14: 000000000056bf80 R15: 000000000000cef7 INFO: task syz-executor.3:10042 blocked for more than 140 seconds. Not tainted 4.19.208-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28200 10042 8445 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 fuse_wait_on_page_writeback fs/fuse/file.c:383 [inline] fuse_wait_on_page_writeback+0xee/0x130 fs/fuse/file.c:379 fuse_launder_page fs/fuse/file.c:2033 [inline] fuse_launder_page+0x92/0xc0 fs/fuse/file.c:2026 do_launder_page mm/truncate.c:655 [inline] invalidate_inode_pages2_range+0x686/0xdb0 mm/truncate.c:725 invalidate_inode_pages2+0x12/0x20 mm/truncate.c:766 fuse_finish_open+0x234/0x4d0 fs/fuse/file.c:182 fuse_open_common+0x1e4/0x240 fs/fuse/file.c:222 fuse_open+0xb/0x10 fs/fuse/file.c:286 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 ksys_open include/linux/syscalls.h:1276 [inline] __do_sys_creat fs/open.c:1143 [inline] __se_sys_creat fs/open.c:1141 [inline] __x64_sys_creat+0x5c/0x80 fs/open.c:1141 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4665f9 Code: 0f 85 c2 00 00 00 48 8d 0d a4 2e 43 00 48 89 88 a8 00 00 00 0f 57 c0 0f 11 84 24 90 00 00 00 48 8b 0d d3 df 36 01 48 89 8c 24 <90> 00 00 00 48 8d 88 e0 00 00 00 48 89 8c 24 98 00 00 00 48 8b 94 RSP: 002b:00007fd8954e6188 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 000000000056c260 RCX: 00000000004665f9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000280 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c260 R13: 00007ffdbce1957f R14: 00007fd8954e6300 R15: 0000000000022000 INFO: task syz-executor.0:10018 blocked for more than 140 seconds. Not tainted 4.19.208-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28232 10018 8453 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] fuse_flush+0x1a2/0x600 fs/fuse/file.c:421 filp_close+0x9a/0x120 fs/open.c:1162 __close_fd+0x100/0x1a0 fs/file.c:636 __do_sys_close fs/open.c:1181 [inline] __se_sys_close+0x3f/0x80 fs/open.c:1179 __x64_sys_close+0x2c/0x40 fs/open.c:1179 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x41940b Code: 00 00 00 48 85 c0 0f 84 9b 07 00 00 0f b6 48 17 83 e1 1f 80 f9 16 0f 85 1a 07 00 00 48 83 78 30 00 0f 84 f6 06 00 00 48 89 84 <24> 90 00 00 00 48 8b 84 24 f0 00 00 00 48 89 04 24 0f 57 c0 0f 11 RSP: 002b:00007ffec4fc3100 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000041940b RDX: 0000000000579ab0 RSI: 00000000000f4240 RDI: 0000000000000004 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000579908 R10: 00049ea10112e9ab R11: 0000000000000293 R12: 000000000000cf70 R13: 00000000000003e8 R14: 000000000056bf80 R15: 000000000000ceff INFO: task syz-executor.0:10046 blocked for more than 140 seconds. Not tainted 4.19.208-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28536 10046 8453 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 fuse_wait_on_page_writeback fs/fuse/file.c:383 [inline] fuse_wait_on_page_writeback+0xee/0x130 fs/fuse/file.c:379 fuse_launder_page fs/fuse/file.c:2033 [inline] fuse_launder_page+0x92/0xc0 fs/fuse/file.c:2026 do_launder_page mm/truncate.c:655 [inline] invalidate_inode_pages2_range+0x686/0xdb0 mm/truncate.c:725 invalidate_inode_pages2+0x12/0x20 mm/truncate.c:766 fuse_finish_open+0x234/0x4d0 fs/fuse/file.c:182 fuse_open_common+0x1e4/0x240 fs/fuse/file.c:222 fuse_open+0xb/0x10 fs/fuse/file.c:286 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 ksys_open include/linux/syscalls.h:1276 [inline] __do_sys_creat fs/open.c:1143 [inline] __se_sys_creat fs/open.c:1141 [inline] __x64_sys_creat+0x5c/0x80 fs/open.c:1141 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4665f9 Code: 0f 85 c2 00 00 00 48 8d 0d a4 2e 43 00 48 89 88 a8 00 00 00 0f 57 c0 0f 11 84 24 90 00 00 00 48 8b 0d d3 df 36 01 48 89 8c 24 <90> 00 00 00 48 8d 88 e0 00 00 00 48 89 8c 24 98 00 00 00 48 8b 94 RSP: 002b:00007f239d683188 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 000000000056c260 RCX: 00000000004665f9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000280 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c260 R13: 00007ffec4fc309f R14: 00007f239d683300 R15: 0000000000022000 Showing all locks held in the system: 2 locks held by kworker/u4:3/669: #0: 000000007006931f (&rq->lock){-.-.}, at: idle_balance kernel/sched/fair.c:9702 [inline] #0: 000000007006931f (&rq->lock){-.-.}, at: pick_next_task_fair+0x1006/0x1540 kernel/sched/fair.c:6841 #1: 00000000bac30991 (rcu_read_lock){....}, at: cpu_of kernel/sched/sched.h:923 [inline] #1: 00000000bac30991 (rcu_read_lock){....}, at: __update_idle_core+0x3c/0x3f0 kernel/sched/fair.c:6057 1 lock held by khungtaskd/1571: #0: 00000000bac30991 (rcu_read_lock){....}, at: debug_show_all_locks+0x5b/0x27a kernel/locking/lockdep.c:4443 1 lock held by in:imklog/7797: 1 lock held by syz-executor.1/9836: #0: 000000001fe0ffe3 (&sb->s_type->i_mutex_key#21){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] #0: 000000001fe0ffe3 (&sb->s_type->i_mutex_key#21){+.+.}, at: fuse_flush+0x1a2/0x600 fs/fuse/file.c:421 2 locks held by syz-executor.1/9888: #0: 000000001aee2b6c (sb_writers#14){.+.+}, at: sb_start_write include/linux/fs.h:1579 [inline] #0: 000000001aee2b6c (sb_writers#14){.+.+}, at: mnt_want_write+0x3c/0xa0 fs/namespace.c:360 #1: 000000001fe0ffe3 (&sb->s_type->i_mutex_key#21){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] #1: 000000001fe0ffe3 (&sb->s_type->i_mutex_key#21){+.+.}, at: fuse_open_common+0x14d/0x240 fs/fuse/file.c:215 1 lock held by syz-executor.4/9902: #0: 00000000825e9b21 (&sb->s_type->i_mutex_key#21){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] #0: 00000000825e9b21 (&sb->s_type->i_mutex_key#21){+.+.}, at: fuse_flush+0x1a2/0x600 fs/fuse/file.c:421 2 locks held by syz-executor.4/9944: #0: 000000001550f351 (sb_writers#14){.+.+}, at: sb_start_write include/linux/fs.h:1579 [inline] #0: 000000001550f351 (sb_writers#14){.+.+}, at: mnt_want_write+0x3c/0xa0 fs/namespace.c:360 #1: 00000000825e9b21 (&sb->s_type->i_mutex_key#21){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] #1: 00000000825e9b21 (&sb->s_type->i_mutex_key#21){+.+.}, at: fuse_open_common+0x14d/0x240 fs/fuse/file.c:215 1 lock held by syz-executor.3/10011: #0: 0000000078ca1e34 (&sb->s_type->i_mutex_key#21){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] #0: 0000000078ca1e34 (&sb->s_type->i_mutex_key#21){+.+.}, at: fuse_flush+0x1a2/0x600 fs/fuse/file.c:421 2 locks held by syz-executor.3/10042: #0: 000000006b6d6804 (sb_writers#14){.+.+}, at: sb_start_write include/linux/fs.h:1579 [inline] #0: 000000006b6d6804 (sb_writers#14){.+.+}, at: mnt_want_write+0x3c/0xa0 fs/namespace.c:360 #1: 0000000078ca1e34 (&sb->s_type->i_mutex_key#21){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] #1: 0000000078ca1e34 (&sb->s_type->i_mutex_key#21){+.+.}, at: fuse_open_common+0x14d/0x240 fs/fuse/file.c:215 1 lock held by syz-executor.0/10018: #0: 0000000015010e78 (&sb->s_type->i_mutex_key#21){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] #0: 0000000015010e78 (&sb->s_type->i_mutex_key#21){+.+.}, at: fuse_flush+0x1a2/0x600 fs/fuse/file.c:421 2 locks held by syz-executor.0/10046: #0: 00000000b1b705af (sb_writers#14){.+.+}, at: sb_start_write include/linux/fs.h:1579 [inline] #0: 00000000b1b705af (sb_writers#14){.+.+}, at: mnt_want_write+0x3c/0xa0 fs/namespace.c:360 #1: 0000000015010e78 (&sb->s_type->i_mutex_key#21){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] #1: 0000000015010e78 (&sb->s_type->i_mutex_key#21){+.+.}, at: fuse_open_common+0x14d/0x240 fs/fuse/file.c:215 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1571 Comm: khungtaskd Not tainted 4.19.208-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 skipped: idling at native_safe_halt+0x12/0x20 arch/x86/include/asm/irqflags.h:60