bisecting fixing commit since f4cc0ed9b2c72687303b035379c5824a02224354 building syzkaller on 7509bf360eba1461ac6059e4cacfbc29c9d2d4c7 testing commit f4cc0ed9b2c72687303b035379c5824a02224354 with gcc (GCC) 8.4.1 20210217 kernel signature: 3040e7e96f047622a431a23a4e089a7b87546860b045c524a54361628be55315 run #0: crashed: BUG: workqueue lockup run #1: crashed: BUG: workqueue lockup run #2: crashed: BUG: workqueue lockup run #3: crashed: BUG: workqueue lockup run #4: crashed: BUG: workqueue lockup run #5: crashed: BUG: workqueue lockup run #6: crashed: BUG: workqueue lockup run #7: crashed: BUG: workqueue lockup run #8: crashed: BUG: workqueue lockup run #9: crashed: BUG: workqueue lockup run #10: crashed: BUG: workqueue lockup run #11: crashed: BUG: workqueue lockup run #12: crashed: BUG: workqueue lockup run #13: crashed: BUG: workqueue lockup run #14: crashed: BUG: workqueue lockup run #15: crashed: INFO: rcu detected stall in corrupted run #16: crashed: INFO: rcu detected stall in corrupted run #17: crashed: INFO: rcu detected stall in corrupted run #18: crashed: INFO: rcu detected stall in ext4_file_write_iter run #19: crashed: INFO: rcu detected stall in corrupted testing current HEAD 3242aa3a635c0958671ee1e4b0958dcc7c4e5c79 testing commit 3242aa3a635c0958671ee1e4b0958dcc7c4e5c79 with gcc (GCC) 8.4.1 20210217 kernel signature: 436c8713bc027df8c75776cfa27f4512dae465bbde4362be028ef4ea9dffab18 run #0: crashed: BUG: workqueue lockup run #1: crashed: BUG: workqueue lockup run #2: crashed: BUG: workqueue lockup run #3: crashed: BUG: workqueue lockup run #4: crashed: BUG: workqueue lockup run #5: crashed: BUG: workqueue lockup run #6: crashed: BUG: workqueue lockup run #7: crashed: BUG: workqueue lockup run #8: crashed: INFO: rcu detected stall in ext4_file_write_iter run #9: crashed: INFO: rcu detected stall in corrupted revisions tested: 2, total time: 24m33.614008122s (build: 14m6.916457851s, test: 9m29.851668085s) the crash still happens on HEAD commit msg: Linux 4.14.222 crash: INFO: rcu detected stall in corrupted IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready IPv6: ADDRCONF(NETDEV_UP): team0: link is not ready 8021q: adding VLAN 0 to HW filter on device team0 INFO: rcu_sched detected stalls on CPUs/tasks: 0-...: (10501 ticks this GP) idle=33a/140000000000000/0 softirq=7459/7460 fqs=15 (detected by 1, t=10502 jiffies, g=195, c=194, q=4) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 6416 Comm: syz-executor.1 Not tainted 4.14.222-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8881e8c7e2c0 task.stack: ffff8881e6c80000 RIP: 0010:__lock_acquire+0x30c/0x4500 kernel/locking/lockdep.c:3408 RSP: 0018:ffff8881e6c87640 EFLAGS: 00000046 RAX: ffff8881e8c7eb48 RBX: 000000000000002a RCX: 0000000000000002 RDX: 0000000000000000 RSI: 1ffff1103d18fd6d RDI: ffff8881e8c7eb68 RBP: ffff8881e6c87810 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000028 R11: ffff8881e8c7e2c0 R12: ffffffff879909e0 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000 FS: 00007f7a9e645700(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000052c071 CR3: 00000001e45df006 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x173/0x400 kernel/locking/lockdep.c:3998 rcu_lock_acquire include/linux/rcupdate.h:242 [inline] rcu_read_lock include/linux/rcupdate.h:629 [inline] aa_file_perm+0xfc/0xa80 security/apparmor/file.c:591 common_file_perm+0x148/0x4d0 security/apparmor/lsm.c:454 apparmor_file_permission+0x15/0x20 security/apparmor/lsm.c:467 security_file_permission+0x6e/0x1c0 security/security.c:865 rw_verify_area+0xb8/0x2b0 fs/read_write.c:386 do_splice_to+0x6f/0x120 fs/splice.c:868 splice_direct_to_actor+0x20d/0x750 fs/splice.c:952 do_splice_direct+0x144/0x250 fs/splice.c:1061 do_sendfile+0x488/0xe60 fs/read_write.c:1441 SYSC_sendfile64 fs/read_write.c:1496 [inline] SyS_sendfile64+0x97/0x110 fs/read_write.c:1488 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x460c99 RSP: 002b:00007f7a9e6451a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 000000000052bf00 RCX: 0000000000460c99 RDX: 0000000020000000 RSI: 0000000000000003 RDI: 0000000000000003 RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000 R10: 00008080fffffffe R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004f5328 R14: 00000000004b2ba5 R15: 00007f7a9e6456bc Code: 4a 8d 44 17 d8 48 ba 00 00 00 00 00 fc ff df 48 8d 78 20 48 89 fe 48 c1 ee 03 0f b6 14 16 84 d2 74 09 80 fa 03 0f 8e bc 0e 00 00 <0f> b7 50 20 81 e2 ff 1f 00 00 39 da 75 0b 48 83 7d 10 00 0f 85 rcu_sched kthread starved for 10472 jiffies! g195 c194 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=1 rcu_sched R running task 29832 9 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x780/0x1d20 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_timeout+0x40c/0xcc0 kernel/time/timer.c:1747 rcu_gp_kthread+0xbbf/0x1e00 kernel/rcu/tree.c:2255 kthread+0x338/0x400 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 INFO: rcu_preempt detected stalls on CPUs/tasks: 0-...: (10551 ticks this GP) idle=33a/140000000000000/0 softirq=7460/7460 fqs=13 (detected by 1, t=10552 jiffies, g=1040, c=1039, q=581) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 6416 Comm: syz-executor.1 Not tainted 4.14.222-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8881e8c7e2c0 task.stack: ffff8881e6c80000 RIP: 0010:radix_tree_lookup_slot+0xa/0x80 lib/radix-tree.c:1076 RSP: 0018:ffff8881e6c87710 EFLAGS: 00000202 RAX: dffffc0000000000 RBX: dffffc0000000000 RCX: 1ffffffff0edb3ac RDX: 0000000000000000 RSI: 0000000000006ee5 RDI: ffff8881d41b94c8 RBP: ffff8881e6c87768 R08: ffff8881e8c7eb90 R09: 0000000000000000 R10: 0000000000000028 R11: ffff8881e8c7e2c0 R12: ffff8881d41b94c0 R13: dffffc0000000000 R14: ffff8881d41b94c0 R15: dffffc0000000000 FS: 00007f7a9e645700(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000052c071 CR3: 00000001e45df006 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: pagecache_get_page+0x45/0x5a0 mm/filemap.c:1465 find_get_page include/linux/pagemap.h:276 [inline] generic_file_buffered_read mm/filemap.c:1999 [inline] generic_file_read_iter+0x622/0x1e80 mm/filemap.c:2273 ext4_file_read_iter+0x139/0x350 fs/ext4/file.c:76 call_read_iter include/linux/fs.h:1772 [inline] generic_file_splice_read+0x349/0x6b0 fs/splice.c:307 do_splice_to+0xe3/0x120 fs/splice.c:880 splice_direct_to_actor+0x20d/0x750 fs/splice.c:952 do_splice_direct+0x144/0x250 fs/splice.c:1061 do_sendfile+0x488/0xe60 fs/read_write.c:1441 SYSC_sendfile64 fs/read_write.c:1496 [inline] SyS_sendfile64+0x97/0x110 fs/read_write.c:1488 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x460c99 RSP: 002b:00007f7a9e6451a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 000000000052bf00 RCX: 0000000000460c99 RDX: 0000000020000000 RSI: 0000000000000003 RDI: 0000000000000003 RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000 R10: 00008080fffffffe R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004f5328 R14: 00000000004b2ba5 R15: 00007f7a9e6456bc Code: 48 89 55 d0 e8 18 37 7a fb 4c 8b 55 c0 48 8b 45 c8 48 8b 55 d0 e9 ea fd ff ff 0f 1f 80 00 00 00 00 48 b8 00 00 00 00 00 fc ff df <55> 31 d2 48 89 e5 53 48 8d 5d 98 48 83 ec 60 48 c7 45 98 b3 8a rcu_preempt kthread starved for 10526 jiffies! g1040 c1039 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=1 rcu_preempt R running task 29720 8 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x780/0x1d20 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_timeout+0x40c/0xcc0 kernel/time/timer.c:1747 rcu_gp_kthread+0xbbf/0x1e00 kernel/rcu/tree.c:2255 kthread+0x338/0x400 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404