Hello, syzbot found the following issue on: HEAD commit: 7b1b868e Merge tag 'for-linus' of git://git.kernel.org/pub.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=17e17137500000 kernel config: https://syzkaller.appspot.com/x/.config?x=3416bb960d5c705d dashboard link: https://syzkaller.appspot.com/bug?extid=46fe899420456e014d6b compiler: gcc (GCC) 10.1.0-syz 20200507 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+46fe899420456e014d6b@xxxxxxxxxxxxxxxxxxxxxxxxx INFO: task syz-executor.0:12044 blocked for more than 143 seconds. Not tainted 5.10.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.0 state:D stack:28152 pid:12044 ppid: 8506 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:3779 [inline] __schedule+0x893/0x2130 kernel/sched/core.c:4528 schedule+0xcf/0x270 kernel/sched/core.c:4606 request_wait_answer+0x552/0x840 fs/fuse/dev.c:411 __fuse_request_send fs/fuse/dev.c:430 [inline] fuse_simple_request+0x58a/0xd10 fs/fuse/dev.c:515 fuse_do_getattr+0x243/0xcb0 fs/fuse/dir.c:1029 fuse_update_get_attr fs/fuse/dir.c:1065 [inline] fuse_getattr+0x3b0/0x470 fs/fuse/dir.c:1801 vfs_getattr_nosec+0x246/0x2e0 fs/stat.c:87 vfs_getattr fs/stat.c:124 [inline] vfs_statx+0x18d/0x390 fs/stat.c:189 vfs_fstatat fs/stat.c:207 [inline] vfs_stat include/linux/fs.h:3121 [inline] __do_sys_newstat+0x91/0x110 fs/stat.c:349 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45e159 RSP: 002b:00007f57f2e19c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000004 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 000000000045e159 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000200004c0 RBP: 000000000119bfb8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf8c R13: 00000000016afb7f R14: 00007f57f2e1a9c0 R15: 000000000119bf8c Showing all locks held in the system: 2 locks held by kworker/u4:0/8: #0: ffff8880b9e34998 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1292 [inline] #0: ffff8880b9e34998 (&rq->lock){-.-.}-{2:2}, at: __schedule+0x21a/0x2130 kernel/sched/core.c:4446 #1: ffff8880b9e20048 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x305/0x440 kernel/sched/psi.c:833 2 locks held by kworker/1:1/34: #0: ffff888010066538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888010066538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888010066538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888010066538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888010066538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888010066538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x821/0x15a0 kernel/workqueue.c:2243 #1: ffffc90000e5fda8 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 kernel/workqueue.c:2247 3 locks held by kworker/u4:4/298: #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x821/0x15a0 kernel/workqueue.c:2243 #1: ffffc90001aafda8 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 kernel/workqueue.c:2247 #2: ffff8880b9e34998 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1292 [inline] #2: ffff8880b9e34998 (&rq->lock){-.-.}-{2:2}, at: __schedule+0x21a/0x2130 kernel/sched/core.c:4446 1 lock held by khungtaskd/1631: #0: ffffffff8b3378e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6254 3 locks held by systemd-udevd/4897: 1 lock held by in:imklog/8170: #0: ffff8880186bcaf0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:932 1 lock held by syz-executor.0/8506: #0: ffff888020e38458 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table_lock+0x41/0x540 net/netfilter/x_tables.c:1206 1 lock held by syz-executor.1/8533: #0: ffff888020e38d88 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table_lock+0x41/0x540 net/netfilter/x_tables.c:1206 1 lock held by syz-executor.3/8756: #0: ffff888020e38d88 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table_lock+0x41/0x540 net/netfilter/x_tables.c:1206 2 locks held by syz-executor.4/8837: #0: ffff888020e38d88 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table_lock+0x41/0x540 net/netfilter/x_tables.c:1206 #1: ffffffff8b33ffa8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline] #1: ffffffff8b33ffa8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x4f2/0x610 kernel/rcu/tree_exp.h:836 2 locks held by syz-executor.2/10213: #0: ffff888020e38458 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table_lock+0x41/0x540 net/netfilter/x_tables.c:1206 #1: ffffffff8b33ffa8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline] #1: ffffffff8b33ffa8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x27e/0x610 kernel/rcu/tree_exp.h:836 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1631 Comm: khungtaskd Not tainted 5.10.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0xd43/0xfa0 kernel/hung_task.c:294 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 18218 Comm: syz-executor.0 Not tainted 5.10.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:unwind_next_frame+0x98/0x1f90 arch/x86/kernel/unwind_orc.c:618 Code: b6 04 02 84 c0 74 08 3c 03 0f 8e 54 0b 00 00 41 8b 2f 31 c0 85 ed 75 3b 48 ba 00 00 00 00 00 fc ff df 48 c7 04 13 00 00 00 00 <48> 8b 9c 24 98 00 00 00 65 48 2b 1c 25 28 00 00 00 0f 85 4a 16 00 RSP: 0000:ffffc900157af888 EFLAGS: 00000286 RAX: 0000000000000001 RBX: 1ffff92002af5f19 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: ffffc900157afef8 RDI: 0000000000000001 RBP: ffffc900157aff28 R08: ffffffff8d62e65a R09: 0000000000000001 R10: 0000000000082081 R11: 0000000000000001 R12: ffffc900157a8000 R13: ffffc900157af995 R14: ffffc900157af9b0 R15: ffffc900157af960 FS: 000000000344a940(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f57f2dd8d90 CR3: 0000000022b2a000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_stack_walk+0x7d/0xe0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:121 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:461 slab_post_alloc_hook mm/slab.h:535 [inline] slab_alloc_node mm/slub.c:2891 [inline] slab_alloc mm/slub.c:2899 [inline] kmem_cache_alloc+0x1c6/0x440 mm/slub.c:2904 anon_vma_chain_alloc mm/rmap.c:136 [inline] __anon_vma_prepare+0x5d/0x560 mm/rmap.c:190 anon_vma_prepare include/linux/rmap.h:153 [inline] do_anonymous_page mm/memory.c:3520 [inline] handle_pte_fault mm/memory.c:4372 [inline] __handle_mm_fault mm/memory.c:4509 [inline] handle_mm_fault+0x87d/0x55d0 mm/memory.c:4607 do_user_addr_fault+0x55b/0xb40 arch/x86/mm/fault.c:1372 handle_page_fault arch/x86/mm/fault.c:1429 [inline] exc_page_fault+0x9e/0x180 arch/x86/mm/fault.c:1485 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:583 RIP: 0033:0x41557f Code: 0f 84 c8 02 00 00 48 83 bd 78 ff ff ff 00 0f 84 f9 04 00 00 48 8b 95 68 ff ff ff 44 89 95 38 ff ff ff 4c 8d ac 10 00 f7 ff ff <49> 89 85 90 06 00 00 49 8d 85 10 03 00 00 49 89 95 98 06 00 00 41 RSP: 002b:00000000016afb10 EFLAGS: 00010206 RAX: 00007f57f2db8000 RBX: 0000000000020000 RCX: 000000000045e1aa RDX: 0000000000021000 RSI: 0000000000021000 RDI: 0000000000000000 RBP: 00000000016afbf0 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000016afce0 R13: 00007f57f2dd8700 R14: 0000000000000003 R15: 000000000119c0dc --- This report is generated by a bot. 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