bisecting fixing commit since 8a61716ff2ab23eddd1f7a05a075a374e4d0c3d4 building syzkaller on 6a5fcca423a42e14346de8637cc30d79530bf034 testing commit 8a61716ff2ab23eddd1f7a05a075a374e4d0c3d4 with gcc (GCC) 8.1.0 kernel signature: 2054eeaed972d8af69270405a3d52648d5370af281b16ea40b628392afe87bdf run #0: crashed: INFO: rcu detected stall in sys_sendfile64 run #1: crashed: INFO: rcu detected stall in sys_sendfile64 run #2: crashed: INFO: rcu detected stall in sys_sendfile64 run #3: crashed: INFO: rcu detected stall in ext4_file_write_iter run #4: crashed: INFO: rcu detected stall in sys_sendfile64 run #5: crashed: INFO: rcu detected stall in sys_sendfile64 run #6: crashed: INFO: rcu detected stall in corrupted run #7: crashed: INFO: rcu detected stall in corrupted run #8: crashed: INFO: rcu detected stall in corrupted run #9: crashed: INFO: rcu detected stall in corrupted testing current HEAD db70e26e33eef1b148ca1c9f50de92203ec7e82e testing commit db70e26e33eef1b148ca1c9f50de92203ec7e82e with gcc (GCC) 8.1.0 kernel signature: 51b92f32f60f8fe40fb202adea830efa355d251488f0493d8239ddbe73109c8a run #0: crashed: INFO: rcu detected stall in corrupted run #1: crashed: INFO: rcu detected stall in ext4_file_write_iter run #2: crashed: INFO: rcu detected stall in sys_sendfile64 run #3: crashed: INFO: rcu detected stall in sys_sendfile64 run #4: crashed: INFO: rcu detected stall in ext4_file_write_iter run #5: crashed: INFO: rcu detected stall in corrupted run #6: crashed: INFO: rcu detected stall in sys_sendfile64 run #7: crashed: INFO: rcu detected stall in corrupted run #8: crashed: INFO: rcu detected stall in sys_sendfile64 run #9: crashed: INFO: rcu detected stall in corrupted revisions tested: 2, total time: 23m9.780365511s (build: 12m6.359966376s, test: 10m4.688035506s) the crash still happens on HEAD commit msg: Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input crash: INFO: rcu detected stall in corrupted IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready 8021q: adding VLAN 0 to HW filter on device batadv0 8021q: adding VLAN 0 to HW filter on device batadv0 rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7617 (detected by 1, t=10503 jiffies, g=5553, q=439) syz-executor.1 R running task 25944 7617 7585 0x00004000 Call Trace: context_switch kernel/sched/core.c:3380 [inline] __schedule+0x856/0x1910 kernel/sched/core.c:4080 preempt_schedule_irq+0x8b/0x120 kernel/sched/core.c:4337 retint_kernel+0x1b/0x2b RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:752 [inline] RIP: 0010:lock_acquire+0x212/0x410 kernel/locking/lockdep.c:4487 Code: 00 00 00 00 00 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 cd 01 00 00 48 83 3d f2 ad 00 07 00 0f 84 54 01 00 00 48 8b 7d c8 57 9d <0f> 1f 44 00 00 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 65 8b RSP: 0018:ffff88807da4f4a0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: ffff88809c778280 RCX: 1ffff1100fb49e7d RDX: 1ffffffff10a6c8f RSI: 0000000000000008 RDI: 0000000000000286 RBP: ffff88807da4f4e8 R08: fffffbfff1394ded R09: fffffbfff1394ded R10: ffff88809c778b40 R11: ffff88809c778280 R12: 0000000000000000 R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:208 [inline] rcu_read_lock include/linux/rcupdate.h:601 [inline] is_bpf_text_address+0x2d/0xe0 kernel/bpf/core.c:705 kernel_text_address+0x79/0x110 kernel/extable.c:150 __kernel_text_address+0xd/0x40 kernel/extable.c:104 unwind_get_return_address+0x61/0xa0 arch/x86/kernel/unwind_frame.c:19 arch_stack_walk+0xa0/0xf0 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x82/0xb0 kernel/stacktrace.c:123 save_stack+0x21/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc.constprop.9+0xc7/0xd0 mm/kasan/common.c:515 kasan_slab_alloc+0x12/0x20 mm/kasan/common.c:523 slab_post_alloc_hook mm/slab.h:584 [inline] slab_alloc mm/slab.c:3320 [inline] __do_kmalloc mm/slab.c:3654 [inline] __kmalloc+0x14a/0x790 mm/slab.c:3665 kmalloc_array include/linux/slab.h:597 [inline] kcalloc include/linux/slab.h:608 [inline] iter_file_splice_write+0x12c/0xb80 fs/splice.c:702 do_splice_from fs/splice.c:863 [inline] direct_splice_actor+0x107/0x1c0 fs/splice.c:1037 splice_direct_to_actor+0x348/0x960 fs/splice.c:992 do_splice_direct+0x14c/0x270 fs/splice.c:1080 do_sendfile+0x481/0xd10 fs/read_write.c:1520 __do_sys_sendfile64 fs/read_write.c:1575 [inline] __se_sys_sendfile64 fs/read_write.c:1567 [inline] __x64_sys_sendfile64+0x12e/0x1e0 fs/read_write.c:1567 do_syscall_64+0xd0/0x600 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457f79 Code: ad b8 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 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fc6bc363c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457f79 RDX: 0000000020000000 RSI: 0000000000000003 RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 00008080fffffffe R11: 0000000000000246 R12: 00007fc6bc3646d4 R13: 00000000004c4e6e R14: 00000000004d8b98 R15: 00000000ffffffff rcu: rcu_preempt kthread starved for 10550 jiffies! g5553 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt I29360 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3380 [inline] __schedule+0x856/0x1910 kernel/sched/core.c:4080 schedule+0xc3/0x2b0 kernel/sched/core.c:4154 schedule_timeout+0x38b/0xad0 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1658 [inline] rcu_gp_kthread+0x9f2/0x1890 kernel/rcu/tree.c:1818 kthread+0x334/0x3f0 kernel/kthread.c:255 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352