bisecting fixing commit since ef244c3088856cf048c77231653b4c92a7b2213c building syzkaller on a41ca8fa8285754d8561dcc3ed54cca2da60eed7 testing commit ef244c3088856cf048c77231653b4c92a7b2213c with gcc (GCC) 8.1.0 kernel signature: 4285680c7ff7e7b7281915a6a674bb28544899934509e700f8ab5d3f87fb5a1a run #0: crashed: INFO: rcu detected stall in ext4_file_read_iter run #1: crashed: INFO: rcu detected stall in ext4_file_read_iter run #2: crashed: INFO: rcu detected stall in corrupted run #3: crashed: INFO: rcu detected stall in sys_open run #4: crashed: INFO: rcu detected stall in sys_open run #5: crashed: INFO: rcu detected stall in corrupted run #6: crashed: INFO: rcu detected stall in sys_open run #7: crashed: INFO: rcu detected stall in sys_open run #8: crashed: INFO: rcu detected stall in sys_open run #9: crashed: INFO: rcu detected stall in corrupted testing current HEAD dce0f88600e49746b4bda873965b671a23ff4313 testing commit dce0f88600e49746b4bda873965b671a23ff4313 with gcc (GCC) 8.1.0 kernel signature: 4d68e96b3bcf25dc7ce91696178b95863f1e6217d91494a52e5c7c44224b3a14 run #0: crashed: INFO: rcu detected stall in corrupted run #1: crashed: INFO: rcu detected stall in sys_open run #2: crashed: INFO: rcu detected stall in sys_open run #3: crashed: INFO: rcu detected stall in sys_open run #4: crashed: INFO: rcu detected stall in sys_open run #5: crashed: INFO: rcu detected stall in corrupted run #6: crashed: INFO: rcu detected stall in sys_open run #7: crashed: INFO: rcu detected stall in corrupted run #8: crashed: INFO: rcu detected stall in sys_open run #9: crashed: INFO: rcu detected stall in sys_open revisions tested: 2, total time: 32m37.010309511s (build: 16m46.342784269s, test: 15m8.145458021s) the crash still happens on HEAD commit msg: Linux 4.19.132 crash: INFO: rcu detected stall in sys_open IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready IPv6: ADDRCONF(NETDEV_UP): team0: link is not ready 8021q: adding VLAN 0 to HW filter on device team0 rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10502 jiffies, g=8849, q=373) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294973088-4294962585), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor.1 R running task 24536 8900 7988 0x80000000 Call Trace: sched_show_task.cold.86+0x2ee/0x35d kernel/sched/core.c:5339 print_other_cpu_stall kernel/rcu/tree.c:1430 [inline] check_cpu_stall kernel/rcu/tree.c:1557 [inline] __rcu_pending kernel/rcu/tree.c:3293 [inline] rcu_pending kernel/rcu/tree.c:3336 [inline] rcu_check_callbacks.cold.81+0xa80/0xd67 kernel/rcu/tree.c:2682 update_process_times+0x2a/0x60 kernel/time/timer.c:1638 tick_sched_handle+0x77/0x140 kernel/time/tick-sched.c:168 tick_sched_timer+0x37/0xf0 kernel/time/tick-sched.c:1278 __run_hrtimer kernel/time/hrtimer.c:1401 [inline] __hrtimer_run_queues+0x2f7/0xab0 kernel/time/hrtimer.c:1463 hrtimer_interrupt+0x2df/0x760 kernel/time/hrtimer.c:1521 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1067 [inline] smp_apic_timer_interrupt+0x114/0x540 arch/x86/kernel/apic/apic.c:1092 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894 RIP: 0010:loop3+0x21f/0x37d Code: c4 43 7b f0 f3 0b 41 31 df 45 31 f5 c4 43 7b f0 f3 06 45 21 df 41 01 f0 45 31 f5 c4 43 7b f0 e0 0d 41 31 df c4 43 7b f0 f0 16 <44> 89 c6 45 31 e6 c4 43 7b f0 e0 02 03 4c 3c 34 44 09 ce 45 31 e6 RSP: 0018:ffff88808a407220 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13 RAX: 000000005f12fffb RBX: 00000000e8a26387 RCX: 00000000b391ed53 RDX: 00000000a96898f3 RSI: 00000000a96b99f3 RDI: 00000000000000c0 RBP: ffff88808a4074b0 R08: 0000000035188e4d R09: 000000002f2b9976 R10: 00000000984f6391 R11: 00000000ad01b7d7 R12: 000000007269a8c4 R13: 00000000249a4d3f R14: 00000000623934d4 R15: 000000004da2f7d3 sha256_avx2_update+0x10/0x20 arch/x86/crypto/sha256_ssse3_glue.c:235 crypto_shash_update+0xd0/0x2e0 crypto/shash.c:126 ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:373 [inline] ima_calc_file_shash security/integrity/ima/ima_crypto.c:393 [inline] ima_calc_file_hash+0x51a/0x800 security/integrity/ima/ima_crypto.c:458 ima_collect_measurement+0x3fc/0x520 security/integrity/ima/ima_api.c:231 process_measurement+0xb0e/0x14b0 security/integrity/ima/ima_main.c:284 ima_file_check+0xc8/0x110 security/integrity/ima/ima_main.c:391 do_last fs/namei.c:3425 [inline] path_openat+0x746/0x3c60 fs/namei.c:3537 do_filp_open+0x177/0x250 fs/namei.c:3567 do_sys_open+0x1dd/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: 0033:0x459fc9 Code: 2d b6 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 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fcd1f5a7c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459fc9 RDX: 0000000000000000 RSI: 0000000000141042 RDI: 0000000020000100 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fcd1f5a86d4 R13: 00000000004fa7ff R14: 00000000004dc210 R15: 00000000ffffffff rcu: rcu_preempt kthread starved for 10545 jiffies! g8849 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29208 10 2 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 schedule_timeout+0x3ab/0xda0 kernel/time/timer.c:1806 rcu_gp_kthread+0xce6/0x23d0 kernel/rcu/tree.c:2202 kthread+0x324/0x3e0 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 audit: type=1800 audit(1594466146.354:29): pid=8900 uid=0 auid=0 ses=8 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed comm="syz-executor.1" name="bus" dev="sda1" ino=15793 res=0 audit: type=1800 audit(1594466146.384:30): pid=8899 uid=0 auid=0 ses=8 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed comm="syz-executor.3" name="bus" dev="sda1" ino=15794 res=0 IPVS: ftp: loaded support on port[0] = 21 audit: type=1800 audit(1594466146.784:31): pid=8914 uid=0 auid=0 ses=8 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed comm="syz-executor.0" name="bus" dev="sda1" ino=15791 res=0 audit: type=1800 audit(1594466146.814:32): pid=8915 uid=0 auid=0 ses=8 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed comm="syz-executor.5" name="bus" dev="sda1" ino=15777 res=0