bisecting fixing commit since e109a984cf380b4b80418b7477c970bfeb428325 building syzkaller on cf9c3a505dd23f7f4e391c0c24c9a9d3b9b26385 testing commit e109a984cf380b4b80418b7477c970bfeb428325 with gcc (GCC) 8.1.0 kernel signature: d87b4db95c4de0aa0abf0a69cb820cf3cbc450b0 all runs: crashed: INFO: task hung in do_exit testing current HEAD 174651bdf802a2139065e8e31ce950e2f3fc4a94 testing commit 174651bdf802a2139065e8e31ce950e2f3fc4a94 with gcc (GCC) 8.1.0 kernel signature: fe2e70f78c2c617ae644748c299bb9f67d1dae11 all runs: crashed: INFO: task hung in do_exit revisions tested: 2, total time: 29m21.751163636s (build: 16m18.233727536s, test: 11m44.941309806s) the crash still happens on HEAD commit msg: Linux 4.19.87 crash: INFO: task hung in do_exit IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready 8021q: adding VLAN 0 to HW filter on device batadv0 INFO: task syz-executor.0:6942 blocked for more than 140 seconds. Not tainted 4.19.87-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28136 6942 6914 0x80000000 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x78c/0x1c10 kernel/sched/core.c:3515 schedule+0x7f/0x1b0 kernel/sched/core.c:3559 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x21c/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 exit_mm kernel/exit.c:512 [inline] do_exit+0x3b7/0x2d40 kernel/exit.c:863 do_group_exit+0xf4/0x2f0 kernel/exit.c:979 __do_sys_exit_group kernel/exit.c:990 [inline] __se_sys_exit_group kernel/exit.c:988 [inline] __x64_sys_exit_group+0x39/0x40 kernel/exit.c:988 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459279 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffddd55f538 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 000000000000001e RCX: 0000000000459279 RDX: 0000000000412f61 RSI: fffffffffffffff7 RDI: 0000000000000000 RBP: 0000000000000000 R08: ffffffffffffffff R09: 00007ffddd55f590 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffddd55f590 R14: 0000000000000000 R15: 00007ffddd55f5a0 INFO: task syz-executor.0:6944 blocked for more than 140 seconds. Not tainted 4.19.87-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28008 6944 6914 0x80000000 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x78c/0x1c10 kernel/sched/core.c:3515 schedule+0x7f/0x1b0 kernel/sched/core.c:3559 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x21c/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 exit_mm kernel/exit.c:512 [inline] do_exit+0x3b7/0x2d40 kernel/exit.c:863 do_group_exit+0xf4/0x2f0 kernel/exit.c:979 get_signal+0x313/0x1a00 kernel/signal.c:2578 do_signal+0x87/0x1960 arch/x86/kernel/signal.c:821 exit_to_usermode_loop+0x114/0x200 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459279 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f06b0ff5cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000075bf28 RCX: 0000000000459279 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000075bf28 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000075bf2c R13: 00007ffddd55f32f R14: 00007f06b0ff69c0 R15: 000000000075bf2c INFO: task syz-executor.0:6961 blocked for more than 140 seconds. Not tainted 4.19.87-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D29000 6961 6914 0x80000000 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x78c/0x1c10 kernel/sched/core.c:3515 schedule+0x7f/0x1b0 kernel/sched/core.c:3559 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x21c/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 exit_mm kernel/exit.c:512 [inline] do_exit+0x3b7/0x2d40 kernel/exit.c:863 do_group_exit+0xf4/0x2f0 kernel/exit.c:979 get_signal+0x313/0x1a00 kernel/signal.c:2578 do_signal+0x87/0x1960 arch/x86/kernel/signal.c:821 exit_to_usermode_loop+0x114/0x200 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459279 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f06b0fd4cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000075bfc8 RCX: 0000000000459279 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000075bfc8 RBP: 000000000075bfc0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000075bfcc R13: 00007ffddd55f32f R14: 00007f06b0fd59c0 R15: 000000000075bfcc INFO: task syz-executor.1:6952 blocked for more than 140 seconds. Not tainted 4.19.87-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D28136 6952 6912 0x80000000 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x78c/0x1c10 kernel/sched/core.c:3515 schedule+0x7f/0x1b0 kernel/sched/core.c:3559 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x21c/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 exit_mm kernel/exit.c:512 [inline] do_exit+0x3b7/0x2d40 kernel/exit.c:863 do_group_exit+0xf4/0x2f0 kernel/exit.c:979 __do_sys_exit_group kernel/exit.c:990 [inline] __se_sys_exit_group kernel/exit.c:988 [inline] __x64_sys_exit_group+0x39/0x40 kernel/exit.c:988 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459279 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffdba551ca8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 000000000000001e RCX: 0000000000459279 RDX: 0000000000412f61 RSI: fffffffffffffff7 RDI: 0000000000000000 RBP: 0000000000000000 R08: ffffffffffffffff R09: 00007ffdba551d00 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffdba551d00 R14: 0000000000000000 R15: 00007ffdba551d10 INFO: task syz-executor.1:6953 blocked for more than 140 seconds. Not tainted 4.19.87-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D28008 6953 6912 0x80000000 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x78c/0x1c10 kernel/sched/core.c:3515 schedule+0x7f/0x1b0 kernel/sched/core.c:3559 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x21c/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 exit_mm kernel/exit.c:512 [inline] do_exit+0x3b7/0x2d40 kernel/exit.c:863 do_group_exit+0xf4/0x2f0 kernel/exit.c:979 get_signal+0x313/0x1a00 kernel/signal.c:2578 do_signal+0x87/0x1960 arch/x86/kernel/signal.c:821 exit_to_usermode_loop+0x114/0x200 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459279 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f44feff7cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000075bf28 RCX: 0000000000459279 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000075bf28 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000075bf2c R13: 00007ffdba551a9f R14: 00007f44feff89c0 R15: 000000000075bf2c INFO: task syz-executor.1:6969 blocked for more than 140 seconds. Not tainted 4.19.87-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D29400 6969 6912 0x80000000 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x78c/0x1c10 kernel/sched/core.c:3515 schedule+0x7f/0x1b0 kernel/sched/core.c:3559 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x21c/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 exit_mm kernel/exit.c:512 [inline] do_exit+0x3b7/0x2d40 kernel/exit.c:863 do_group_exit+0xf4/0x2f0 kernel/exit.c:979 get_signal+0x313/0x1a00 kernel/signal.c:2578 do_signal+0x87/0x1960 arch/x86/kernel/signal.c:821 exit_to_usermode_loop+0x114/0x200 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459279 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f44fefd6cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000075bfc8 RCX: 0000000000459279 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000075bfc8 RBP: 000000000075bfc0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000075bfcc R13: 00007ffdba551a9f R14: 00007f44fefd79c0 R15: 000000000075bfcc INFO: task syz-executor.3:6954 blocked for more than 140 seconds. Not tainted 4.19.87-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28136 6954 6910 0x80000000 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x78c/0x1c10 kernel/sched/core.c:3515 schedule+0x7f/0x1b0 kernel/sched/core.c:3559 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x21c/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 exit_mm kernel/exit.c:512 [inline] do_exit+0x3b7/0x2d40 kernel/exit.c:863 do_group_exit+0xf4/0x2f0 kernel/exit.c:979 __do_sys_exit_group kernel/exit.c:990 [inline] __se_sys_exit_group kernel/exit.c:988 [inline] __x64_sys_exit_group+0x39/0x40 kernel/exit.c:988 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459279 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fffe19fcf98 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 000000000000001e RCX: 0000000000459279 RDX: 0000000000412f61 RSI: fffffffffffffff7 RDI: 0000000000000000 RBP: 0000000000000000 R08: ffffffffffffffff R09: 00007fffe19fcff0 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000001 R13: 00007fffe19fcff0 R14: 0000000000000000 R15: 00007fffe19fd000 INFO: task syz-executor.3:6957 blocked for more than 140 seconds. Not tainted 4.19.87-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28008 6957 6910 0x80000000 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x78c/0x1c10 kernel/sched/core.c:3515 schedule+0x7f/0x1b0 kernel/sched/core.c:3559 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x21c/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 exit_mm kernel/exit.c:512 [inline] do_exit+0x3b7/0x2d40 kernel/exit.c:863 do_group_exit+0xf4/0x2f0 kernel/exit.c:979 get_signal+0x313/0x1a00 kernel/signal.c:2578 do_signal+0x87/0x1960 arch/x86/kernel/signal.c:821 exit_to_usermode_loop+0x114/0x200 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459279 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f8ed533ecf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000075bf28 RCX: 0000000000459279 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000075bf28 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000075bf2c R13: 00007fffe19fcd8f R14: 00007f8ed533f9c0 R15: 000000000075bf2c INFO: task syz-executor.3:6970 blocked for more than 140 seconds. Not tainted 4.19.87-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D29192 6970 6910 0x80000000 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x78c/0x1c10 kernel/sched/core.c:3515 schedule+0x7f/0x1b0 kernel/sched/core.c:3559 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x21c/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 exit_mm kernel/exit.c:512 [inline] do_exit+0x3b7/0x2d40 kernel/exit.c:863 do_group_exit+0xf4/0x2f0 kernel/exit.c:979 get_signal+0x313/0x1a00 kernel/signal.c:2578 do_signal+0x87/0x1960 arch/x86/kernel/signal.c:821 exit_to_usermode_loop+0x114/0x200 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459279 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f8ed531dcf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000075bfc8 RCX: 0000000000459279 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000075bfc8 RBP: 000000000075bfc0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000075bfcc R13: 00007fffe19fcd8f R14: 00007f8ed531e9c0 R15: 000000000075bfcc INFO: task syz-executor.2:6960 blocked for more than 140 seconds. Not tainted 4.19.87-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28136 6960 6907 0x80000004 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x78c/0x1c10 kernel/sched/core.c:3515 schedule+0x7f/0x1b0 kernel/sched/core.c:3559 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x21c/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 exit_mm kernel/exit.c:512 [inline] do_exit+0x3b7/0x2d40 kernel/exit.c:863 do_group_exit+0xf4/0x2f0 kernel/exit.c:979 get_signal+0x313/0x1a00 kernel/signal.c:2578 do_signal+0x87/0x1960 arch/x86/kernel/signal.c:821 exit_to_usermode_loop+0x114/0x200 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4592ca Code: 89 f5 41 54 49 89 fc 55 53 74 35 49 63 e8 48 63 da 4d 89 f9 49 89 e8 4d 63 d6 48 89 da 4c 89 ee 4c 89 e7 b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 4e 5b 5d 41 5c 41 5d 41 5e 41 5f c3 0f 1f 00 RSP: 002b:00007fff9d946a28 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: fffffffffffffffc RBX: 0000000000000003 RCX: 00000000004592ca RDX: 0000000000000003 RSI: 0000000000021000 RDI: 0000000000000000 RBP: ffffffffffffffff R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000020022 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000021000 R14: 0000000000020022 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/1031: #0: 00000000446f2043 (rcu_read_lock){....}, at: debug_show_all_locks+0x5b/0x27a kernel/locking/lockdep.c:4438 1 lock held by rsyslogd/6665: #0: 00000000db2de79e (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xa7/0xd0 fs/file.c:767 2 locks held by getty/6787: #0: 0000000086e5e4ae (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:362 #1: 00000000c35fd176 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x1ee/0x18d0 drivers/tty/n_tty.c:2154 2 locks held by getty/6788: #0: 00000000287c837f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:362 #1: 000000008e1602b9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x1ee/0x18d0 drivers/tty/n_tty.c:2154 2 locks held by getty/6789: #0: 000000003a858b4d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:362 #1: 0000000062c0206d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x1ee/0x18d0 drivers/tty/n_tty.c:2154 2 locks held by getty/6790: #0: 00000000d99345fa (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:362 #1: 000000003009450e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x1ee/0x18d0 drivers/tty/n_tty.c:2154 2 locks held by getty/6792: #0: 0000000023ba50b6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:362 #1: 00000000061151c4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x1ee/0x18d0 drivers/tty/n_tty.c:2154 2 locks held by getty/6793: #0: 000000006105048a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:362 #1: 000000009a83fdf4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x1ee/0x18d0 drivers/tty/n_tty.c:2154 2 locks held by getty/6794: #0: 0000000091900296 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:362 #1: 000000007a9b022e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x1ee/0x18d0 drivers/tty/n_tty.c:2154 1 lock held by syz-executor.0/6942: #0: 00000000153335c3 (&mm->mmap_sem){++++}, at: exit_mm kernel/exit.c:512 [inline] #0: 00000000153335c3 (&mm->mmap_sem){++++}, at: do_exit+0x3b7/0x2d40 kernel/exit.c:863 1 lock held by syz-executor.0/6944: #0: 00000000153335c3 (&mm->mmap_sem){++++}, at: exit_mm kernel/exit.c:512 [inline] #0: 00000000153335c3 (&mm->mmap_sem){++++}, at: do_exit+0x3b7/0x2d40 kernel/exit.c:863 1 lock held by syz-executor.0/6961: #0: 00000000153335c3 (&mm->mmap_sem){++++}, at: exit_mm kernel/exit.c:512 [inline] #0: 00000000153335c3 (&mm->mmap_sem){++++}, at: do_exit+0x3b7/0x2d40 kernel/exit.c:863 1 lock held by syz-executor.0/6964: 1 lock held by syz-executor.1/6952: #0: 00000000f32b8f67 (&mm->mmap_sem){++++}, at: exit_mm kernel/exit.c:512 [inline] #0: 00000000f32b8f67 (&mm->mmap_sem){++++}, at: do_exit+0x3b7/0x2d40 kernel/exit.c:863 1 lock held by syz-executor.1/6953: #0: 00000000f32b8f67 (&mm->mmap_sem){++++}, at: exit_mm kernel/exit.c:512 [inline] #0: 00000000f32b8f67 (&mm->mmap_sem){++++}, at: do_exit+0x3b7/0x2d40 kernel/exit.c:863 1 lock held by syz-executor.1/6969: #0: 00000000f32b8f67 (&mm->mmap_sem){++++}, at: exit_mm kernel/exit.c:512 [inline] #0: 00000000f32b8f67 (&mm->mmap_sem){++++}, at: do_exit+0x3b7/0x2d40 kernel/exit.c:863 1 lock held by syz-executor.1/6973: 1 lock held by syz-executor.3/6954: #0: 00000000424c4bb0 (&mm->mmap_sem){++++}, at: exit_mm kernel/exit.c:512 [inline] #0: 00000000424c4bb0 (&mm->mmap_sem){++++}, at: do_exit+0x3b7/0x2d40 kernel/exit.c:863 1 lock held by syz-executor.3/6957: #0: 00000000424c4bb0 (&mm->mmap_sem){++++}, at: exit_mm kernel/exit.c:512 [inline] #0: 00000000424c4bb0 (&mm->mmap_sem){++++}, at: do_exit+0x3b7/0x2d40 kernel/exit.c:863 1 lock held by syz-executor.3/6970: #0: 00000000424c4bb0 (&mm->mmap_sem){++++}, at: exit_mm kernel/exit.c:512 [inline] #0: 00000000424c4bb0 (&mm->mmap_sem){++++}, at: do_exit+0x3b7/0x2d40 kernel/exit.c:863 1 lock held by syz-executor.3/6974: 1 lock held by syz-executor.2/6960: #0: 0000000083c39a80 (&mm->mmap_sem){++++}, at: exit_mm kernel/exit.c:512 [inline] #0: 0000000083c39a80 (&mm->mmap_sem){++++}, at: do_exit+0x3b7/0x2d40 kernel/exit.c:863 6 locks held by syz-executor.2/6962: 1 lock held by syz-executor.2/6972: #0: 0000000083c39a80 (&mm->mmap_sem){++++}, at: exit_mm kernel/exit.c:512 [inline] #0: 0000000083c39a80 (&mm->mmap_sem){++++}, at: do_exit+0x3b7/0x2d40 kernel/exit.c:863 1 lock held by syz-executor.4/6978: #0: 00000000db467f09 (&mm->mmap_sem){++++}, at: exit_mm kernel/exit.c:512 [inline] #0: 00000000db467f09 (&mm->mmap_sem){++++}, at: do_exit+0x3b7/0x2d40 kernel/exit.c:863 1 lock held by syz-executor.4/6979: 1 lock held by syz-executor.4/6982: #0: 00000000db467f09 (&mm->mmap_sem){++++}, at: exit_mm kernel/exit.c:512 [inline] #0: 00000000db467f09 (&mm->mmap_sem){++++}, at: do_exit+0x3b7/0x2d40 kernel/exit.c:863 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1031 Comm: khungtaskd Not tainted 4.19.87-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+0x123/0x177 lib/dump_stack.c:118 nmi_cpu_backtrace.cold.4+0x3e/0x76 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0xe6/0x11a 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+0x324/0x3e0 kernel/kthread.c:246 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: 2351 Comm: kworker/u4:4 Not tainted 4.19.87-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:__lock_acquire+0x21d/0x4980 kernel/locking/lockdep.c:3294 Code: 84 4a ff ff ff 83 fe 01 0f 87 4d ff ff ff 48 b8 00 00 00 00 00 fc ff df 89 f3 49 8d 7c dd 08 48 89 fa 48 c1 ea 03 80 3c 02 00 <0f> 85 cd 31 00 00 49 8b 5c dd 08 48 85 db 0f 84 1d ff ff ff 48 8d RSP: 0018:ffff8880a1b57a90 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000002 RDX: 1ffffffff0ff339d RSI: 0000000000000000 RDI: ffffffff87f99ce8 RBP: ffff8880a1b57c80 R08: 0000000000000000 R09: 0000000000000000 R10: ffffed1015d44732 R11: ffff8880aea23993 R12: 0000000000000000 R13: ffffffff87f99ce0 R14: ffff8880a1b42340 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 000000008475a000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x173/0x3d0 kernel/locking/lockdep.c:3903 rcu_lock_acquire include/linux/rcupdate.h:242 [inline] rcu_read_lock include/linux/rcupdate.h:627 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:419 [inline] batadv_nc_worker+0xec/0x630 net/batman-adv/network-coding.c:730 process_one_work+0x830/0x1670 kernel/workqueue.c:2153 worker_thread+0x85/0xb60 kernel/workqueue.c:2296 kthread+0x324/0x3e0 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415