bisecting fixing commit since ef244c3088856cf048c77231653b4c92a7b2213c building syzkaller on a41ca8fa8285754d8561dcc3ed54cca2da60eed7 testing commit ef244c3088856cf048c77231653b4c92a7b2213c with gcc (GCC) 8.1.0 kernel signature: 360cde032dccc44ff066c452ecbb39894bd4723d538e8773a943bc772af6e05a run #0: crashed: INFO: rcu detected stall in sys_open 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 corrupted 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 961f830af0658ef5ef8a7708786d634a6115f16b testing commit 961f830af0658ef5ef8a7708786d634a6115f16b with gcc (GCC) 8.1.0 kernel signature: 2aea233b00bacff67a7e4955f4d692b2468591e250f34b4dbde94c4654fb5285 run #0: crashed: INFO: rcu detected stall in ext4_file_read_iter run #1: crashed: INFO: rcu detected stall in sys_open 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 ext4_file_read_iter run #9: crashed: INFO: rcu detected stall in ext4_file_read_iter revisions tested: 2, total time: 27m48.326487574s (build: 17m8.224002664s, test: 9m16.82885948s) the crash still happens on HEAD commit msg: Linux 4.19.138 crash: INFO: rcu detected stall in ext4_file_read_iter IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_team: link becomes ready hrtimer: interrupt took 46273 ns rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10502 jiffies, g=4945, q=322) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294952439-4294941936), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor.3 R running task 24488 7286 6375 0x80000000 Call Trace: sched_show_task.cold.86+0x2ee/0x35d kernel/sched/core.c:5341 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+0x28/0x90 kernel/time/timer.c:1650 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:memory_is_nonzero mm/kasan/kasan.c:196 [inline] RIP: 0010:memory_is_poisoned_n mm/kasan/kasan.c:210 [inline] RIP: 0010:memory_is_poisoned mm/kasan/kasan.c:241 [inline] RIP: 0010:check_memory_region_inline mm/kasan/kasan.c:257 [inline] RIP: 0010:check_memory_region+0xa2/0x1b0 mm/kasan/kasan.c:267 Code: 03 45 85 c9 0f 84 23 01 00 00 48 83 38 00 75 1c 45 8d 41 ff 4a 8d 5c c0 08 48 83 c0 08 48 39 c3 0f 84 a8 00 00 00 48 83 38 00 <74> ed 4c 8d 40 08 eb 09 48 83 c0 01 49 39 c0 74 0a 80 38 00 74 f2 RSP: 0018:ffff888093d0ec18 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffffed102cc74900 RBX: ffffed102cc74a00 RCX: ffffffff81d8af60 RDX: 0000000000000001 RSI: 0000000000001000 RDI: ffff8881663a4000 RBP: ffff888093d0ec30 R08: 000000000000003f R09: 0000000000000040 R10: ffffed102cc749ff R11: ffff8881663a4fff R12: ffffed102cc74a00 R13: 0000000000000000 R14: dffffc0000000000 R15: 000000000008c88c memset+0x23/0x40 mm/kasan/kasan.c:285 memset include/linux/string.h:358 [inline] zero_user_segments include/linux/highmem.h:203 [inline] zero_user_segment include/linux/highmem.h:215 [inline] ext4_mpage_readpages+0x7e0/0x1560 fs/ext4/readpage.c:217 ext4_readpages+0xae/0x100 fs/ext4/inode.c:3364 read_pages+0xed/0x470 mm/readahead.c:123 __do_page_cache_readahead+0x35c/0x560 mm/readahead.c:211 ra_submit mm/internal.h:66 [inline] ondemand_readahead+0x42b/0xbc0 mm/readahead.c:493 page_cache_async_readahead+0x311/0x5e0 mm/readahead.c:575 generic_file_buffered_read mm/filemap.c:2123 [inline] generic_file_read_iter+0x121f/0x20d0 mm/filemap.c:2385 ext4_file_read_iter+0x139/0x350 fs/ext4/file.c:78 call_read_iter include/linux/fs.h:1815 [inline] new_sync_read fs/read_write.c:406 [inline] __vfs_read+0x440/0x880 fs/read_write.c:418 integrity_kernel_read+0x128/0x200 security/integrity/iint.c:200 ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:364 [inline] ima_calc_file_shash security/integrity/ima/ima_crypto.c:393 [inline] ima_calc_file_hash+0x53a/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:00007f0b09b7fc78 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: 00007f0b09b806d4 R13: 00000000004fa7ff R14: 00000000004dc210 R15: 00000000ffffffff rcu: rcu_preempt kthread starved for 10556 jiffies! g4945 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:2828 [inline] __schedule+0x78c/0x1c10 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x3ab/0xe00 kernel/time/timer.c:1825 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