bisecting fixing commit since 64b4fc45bea6f4faa843d2f97ff51665280efee1 building syzkaller on be2c130d4c0c511da96ce278486cf0564aeadcea testing commit 64b4fc45bea6f4faa843d2f97ff51665280efee1 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: a3fe91368b5fd3fe51bac40c148f21c0653a715c54c44e14f6b308a6932bebe8 all runs: crashed: INFO: task hung in __sync_dirty_buffer testing current HEAD d58071a8a76d779eedab38033ae4c821c30295a5 testing commit d58071a8a76d779eedab38033ae4c821c30295a5 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 5d0c46495f9acffda9c70fb3afe1ecd09b573fc6b6196478aa3cf71c3590ef06 run #0: boot failed: create image operation failed: &{Code:ZONE_RESOURCE_POOL_EXHAUSTED_WITH_DETAILS Location: Message:The zone 'projects/syzkaller/zones/us-central1-c' does not have enough resources available to fulfill the request. '(resource type:compute)'. ForceSendFields:[] NullFields:[]}. run #1: crashed: INFO: task hung in __sync_dirty_buffer run #2: crashed: INFO: task hung in __sync_dirty_buffer run #3: crashed: INFO: task hung in __sync_dirty_buffer run #4: crashed: INFO: task hung in __sync_dirty_buffer run #5: crashed: INFO: task hung in __sync_dirty_buffer run #6: crashed: INFO: task hung in __sync_dirty_buffer run #7: crashed: INFO: task hung in __sync_dirty_buffer run #8: crashed: INFO: task hung in __sync_dirty_buffer run #9: crashed: INFO: task hung in __sync_dirty_buffer revisions tested: 2, total time: 25m2.307268907s (build: 12m43.248127373s, test: 11m35.410107454s) the crash still happens on HEAD commit msg: Linux 5.16-rc3 crash: INFO: task hung in __sync_dirty_buffer INFO: task syz-executor.0:8896 blocked for more than 143 seconds. Not tainted 5.16.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.0 state:D stack:26448 pid: 8896 ppid: 7071 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4972 [inline] __schedule+0x90d/0x26c0 kernel/sched/core.c:6253 schedule+0xd2/0x260 kernel/sched/core.c:6326 io_schedule+0xee/0x170 kernel/sched/core.c:8371 bit_wait_io+0x12/0xd0 kernel/sched/wait_bit.c:209 __wait_on_bit_lock+0x121/0x1a0 kernel/sched/wait_bit.c:90 out_of_line_wait_on_bit_lock+0xd5/0x110 kernel/sched/wait_bit.c:117 wait_on_bit_lock_io include/linux/wait_bit.h:208 [inline] __lock_buffer fs/buffer.c:69 [inline] lock_buffer include/linux/buffer_head.h:368 [inline] __sync_dirty_buffer+0x287/0x310 fs/buffer.c:3142 __ext4_handle_dirty_metadata+0x1c4/0x680 fs/ext4/ext4_jbd2.c:380 ext4_convert_inline_data_nolock+0x5c9/0xfe0 fs/ext4/inline.c:1252 ext4_convert_inline_data+0x297/0x3d0 fs/ext4/inline.c:2024 ext4_fallocate+0x150/0x3310 fs/ext4/extents.c:4707 vfs_fallocate+0x2a5/0xb90 fs/open.c:307 ksys_fallocate fs/open.c:330 [inline] __do_sys_fallocate fs/open.c:338 [inline] __se_sys_fallocate fs/open.c:336 [inline] __x64_sys_fallocate+0xb0/0x100 fs/open.c:336 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665f9 RSP: 002b:00007fe3f19c8188 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665f9 RDX: 0000000000000000 RSI: 0000000100000001 RDI: 0000000000000006 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 000000002811fdff R11: 0000000000000246 R12: 000000000056bf80 R13: 00007fff38a87a8f R14: 00007fe3f19c8300 R15: 0000000000022000 INFO: task syz-executor.0:8953 blocked for more than 143 seconds. Not tainted 5.16.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.0 state:D stack:26864 pid: 8953 ppid: 7071 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4972 [inline] __schedule+0x90d/0x26c0 kernel/sched/core.c:6253 schedule+0xd2/0x260 kernel/sched/core.c:6326 io_schedule+0xee/0x170 kernel/sched/core.c:8371 bit_wait_io+0x12/0xd0 kernel/sched/wait_bit.c:209 __wait_on_bit_lock+0x121/0x1a0 kernel/sched/wait_bit.c:90 out_of_line_wait_on_bit_lock+0xd5/0x110 kernel/sched/wait_bit.c:117 wait_on_bit_lock_io include/linux/wait_bit.h:208 [inline] __lock_buffer fs/buffer.c:69 [inline] lock_buffer include/linux/buffer_head.h:368 [inline] write_dirty_buffer+0x10f/0x120 fs/buffer.c:3121 fsync_buffers_list fs/buffer.c:705 [inline] sync_mapping_buffers+0x300/0x970 fs/buffer.c:548 ext4_fsync_nojournal fs/ext4/fsync.c:86 [inline] ext4_sync_file+0x74c/0xc90 fs/ext4/fsync.c:170 generic_write_sync include/linux/fs.h:2955 [inline] ext4_buffered_write_iter+0x256/0x330 fs/ext4/file.c:277 ext4_file_write_iter+0x383/0x1160 fs/ext4/file.c:681 call_write_iter include/linux/fs.h:2162 [inline] new_sync_write+0x360/0x600 fs/read_write.c:503 vfs_write+0x609/0x900 fs/read_write.c:590 ksys_write+0xf4/0x1d0 fs/read_write.c:643 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665f9 RSP: 002b:00007fe3f19a7188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665f9 RDX: 0000000000000082 RSI: 00000000200004c0 RDI: 0000000000000004 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c038 R13: 00007fff38a87a8f R14: 00007fe3f19a7300 R15: 0000000000022000 Showing all locks held in the system: 3 locks held by kworker/u4:1/10: #0: ffff8880b9e39a58 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x1e/0x30 kernel/sched/core.c:478 #1: ffff8880b9e279c8 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x3a6/0x490 kernel/sched/psi.c:880 #2: ffffffff8ab78980 (rcu_read_lock){....}-{1:2}, at: batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:410 [inline] #2: ffffffff8ab78980 (rcu_read_lock){....}-{1:2}, at: batadv_nc_worker+0xd3/0xd70 net/batman-adv/network-coding.c:723 1 lock held by khungtaskd/27: #0: ffffffff8ab78980 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6458 1 lock held by in:imklog/6243: 2 locks held by syz-executor.0/8896: #0: ffff88807480e460 (sb_writers#5){.+.+}-{0:0}, at: ksys_fallocate fs/open.c:330 [inline] #0: ffff88807480e460 (sb_writers#5){.+.+}-{0:0}, at: __do_sys_fallocate fs/open.c:338 [inline] #0: ffff88807480e460 (sb_writers#5){.+.+}-{0:0}, at: __se_sys_fallocate fs/open.c:336 [inline] #0: ffff88807480e460 (sb_writers#5){.+.+}-{0:0}, at: __x64_sys_fallocate+0xb0/0x100 fs/open.c:336 #1: ffff88806b7dda80 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:142 [inline] #1: ffff88806b7dda80 (&ei->xattr_sem){++++}-{3:3}, at: ext4_convert_inline_data+0x1ca/0x3d0 fs/ext4/inline.c:2022 2 locks held by syz-executor.0/8953: #0: ffff888072aeb770 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x9c/0xb0 fs/file.c:990 #1: ffff88807480e460 (sb_writers#5){.+.+}-{0:0}, at: ksys_write+0xf4/0x1d0 fs/read_write.c:643 2 locks held by syz-executor.2/9309: #0: ffff88807eaa2460 (sb_writers#5){.+.+}-{0:0}, at: ksys_fallocate fs/open.c:330 [inline] #0: ffff88807eaa2460 (sb_writers#5){.+.+}-{0:0}, at: __do_sys_fallocate fs/open.c:338 [inline] #0: ffff88807eaa2460 (sb_writers#5){.+.+}-{0:0}, at: __se_sys_fallocate fs/open.c:336 [inline] #0: ffff88807eaa2460 (sb_writers#5){.+.+}-{0:0}, at: __x64_sys_fallocate+0xb0/0x100 fs/open.c:336 #1: ffff88806b71ee70 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:142 [inline] #1: ffff88806b71ee70 (&ei->xattr_sem){++++}-{3:3}, at: ext4_convert_inline_data+0x1ca/0x3d0 fs/ext4/inline.c:2022 2 locks held by syz-executor.2/9316: #0: ffff88801865cd70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x9c/0xb0 fs/file.c:990 #1: ffff88807eaa2460 (sb_writers#5){.+.+}-{0:0}, at: ksys_write+0xf4/0x1d0 fs/read_write.c:643 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.16.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x57/0x7d lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x30/0xc0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x11f/0x170 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline] watchdog+0x88c/0xbf0 kernel/hung_task.c:295 kthread+0x3ab/0x480 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 45 Comm: kworker/u4:2 Not tainted 5.16.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:check_preemption_disabled+0x29/0xe0 lib/smp_processor_id.c:56 Code: cc 41 54 55 53 48 83 ec 08 65 44 8b 25 b8 1b 8a 77 65 8b 05 29 76 8a 77 a9 ff ff ff 7f 74 0c 48 83 c4 08 44 89 e0 5b 5d 41 5c 9c 58 f6 c4 02 74 ed 65 48 8b 04 25 40 70 02 00 f6 40 2f 04 48 RSP: 0018:ffffc9000115f9f8 EFLAGS: 00000092 RAX: 0000000000000000 RBX: ffffffff8c810000 RCX: ffffffffffffffff RDX: ffff8880115d0000 RSI: ffffffff892163e0 RDI: ffffffff89216420 RBP: ffff888140738000 R08: 8000000001a7b063 R09: 0000000000000003 R10: ffffffff8c819290 R11: 0000000000000000 R12: ffffffff8ac9eec0 R13: ffff8880115d0000 R14: 000000008c810000 R15: ffffffff8ac9ee00 FS: 0000000000000000(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fead4c93000 CR3: 000000000a88e000 CR4: 0000000000350ef0 Call Trace: switch_mm_irqs_off+0x34/0xa10 arch/x86/mm/tlb.c:494 use_temporary_mm arch/x86/kernel/alternative.c:924 [inline] __text_poke+0x44a/0x8c0 arch/x86/kernel/alternative.c:1021 text_poke_bp_batch+0x3d9/0x560 arch/x86/kernel/alternative.c:1361 text_poke_flush arch/x86/kernel/alternative.c:1451 [inline] text_poke_flush arch/x86/kernel/alternative.c:1448 [inline] text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1458 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x15f/0x220 kernel/jump_label.c:177 static_key_enable+0x11/0x20 kernel/jump_label.c:190 toggle_allocation_gate mm/kfence/core.c:732 [inline] toggle_allocation_gate+0xe3/0x310 mm/kfence/core.c:724 process_one_work+0x87f/0x1450 kernel/workqueue.c:2298 worker_thread+0x598/0x1040 kernel/workqueue.c:2445 kthread+0x3ab/0x480 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 ---------------- Code disassembly (best guess): 0: cc int3 1: 41 54 push %r12 3: 55 push %rbp 4: 53 push %rbx 5: 48 83 ec 08 sub $0x8,%rsp 9: 65 44 8b 25 b8 1b 8a mov %gs:0x778a1bb8(%rip),%r12d # 0x778a1bc9 10: 77 11: 65 8b 05 29 76 8a 77 mov %gs:0x778a7629(%rip),%eax # 0x778a7641 18: a9 ff ff ff 7f test $0x7fffffff,%eax 1d: 74 0c je 0x2b 1f: 48 83 c4 08 add $0x8,%rsp 23: 44 89 e0 mov %r12d,%eax 26: 5b pop %rbx 27: 5d pop %rbp 28: 41 5c pop %r12 * 2a: c3 retq <-- trapping instruction 2b: 9c pushfq 2c: 58 pop %rax 2d: f6 c4 02 test $0x2,%ah 30: 74 ed je 0x1f 32: 65 48 8b 04 25 40 70 mov %gs:0x27040,%rax 39: 02 00 3b: f6 40 2f 04 testb $0x4,0x2f(%rax) 3f: 48 rex.W