Hello, When using Syzkaller to fuzz the latest Linux kernel, the following crash was triggered. HEAD commit: a7904a538933 Linux 5.16-rc6 git tree: upstream console output: https://paste.ubuntu.com/p/ttm2fNzkvN/ kernel config: https://paste.ubuntu.com/p/FDDNHDxtwz/plain/ Sorry, I don't have a reproducer for this crash, hope the symbolized report can help. If you fix this issue, please add the following tag to the commit: Reported-by: Yiru Xu <xyru1999@xxxxxxxxx> INFO: task rs:main Q:Reg:6758 blocked for more than 143 seconds. Not tainted 5.16.0-rc6 #9 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:rs:main Q:Reg state:D stack:25832 pid: 6758 ppid: 1 flags:0x00000000 Call Trace: <TASK> context_switch kernel/sched/core.c:4972 [inline] __schedule+0xcd9/0x2530 kernel/sched/core.c:6253 schedule+0xd2/0x260 kernel/sched/core.c:6326 io_schedule+0xb3/0x120 kernel/sched/core.c:8371 folio_wait_bit_common+0x524/0xa30 mm/filemap.c:1371 __folio_lock mm/filemap.c:1649 [inline] folio_lock include/linux/pagemap.h:783 [inline] __filemap_get_folio+0xdd1/0x1080 mm/filemap.c:1921 pagecache_get_page+0x2c/0x1a0 mm/folio-compat.c:125 ext4_da_write_begin+0x3bc/0xad0 fs/ext4/inode.c:2958 generic_perform_write+0x201/0x510 mm/filemap.c:3754 ext4_buffered_write_iter+0x170/0x360 fs/ext4/file.c:269 ext4_file_write_iter+0x42e/0x14a0 fs/ext4/file.c:681 call_write_iter include/linux/fs.h:2162 [inline] new_sync_write+0x432/0x660 fs/read_write.c:503 vfs_write+0x678/0xae0 fs/read_write.c:590 ksys_write+0x12d/0x250 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: 0033:0x7ff8402951cd RSP: 002b:00007ff83d850590 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007ff834021940 RCX: 00007ff8402951cd RDX: 0000000000000095 RSI: 00007ff834021940 RDI: 0000000000000006 RBP: 0000000000000000 R08: 0000000000000000 R09: 35313620205b203a R10: 0000000000000000 R11: 0000000000000293 R12: 00007ff8340216c0 R13: 00007ff83d8505b0 R14: 000055f3ac883360 R15: 0000000000000095 </TASK> Showing all locks held in the system: 1 lock held by systemd/1: #0: ffff8880163dd550 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:838 [inline] #0: ffff8880163dd550 (mapping.invalidate_lock){++++}-{3:3}, at: page_cache_ra_unbounded+0x1bc/0x950 mm/readahead.c:194 1 lock held by khungtaskd/39: #0: ffffffff8bb80e20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6458 3 locks held by kswapd0/122: 2 locks held by kswapd1/123: #0: ffffffff8bca5140 (fs_reclaim){+.+.}-{0:0}, at: try_to_freeze_unsafe include/linux/freezer.h:58 [inline] #0: ffffffff8bca5140 (fs_reclaim){+.+.}-{0:0}, at: try_to_freeze include/linux/freezer.h:67 [inline] #0: ffffffff8bca5140 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0xc63/0x1190 mm/vmscan.c:4227 #1: ffff8881104ca430 (&mapping->i_mmap_rwsem){++++}-{3:3}, at: i_mmap_lock_read include/linux/fs.h:513 [inline] #1: ffff8881104ca430 (&mapping->i_mmap_rwsem){++++}-{3:3}, at: rmap_walk_file+0x86d/0xc20 mm/rmap.c:2345 1 lock held by systemd-journal/3053: #0: ffffffff8bca5140 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4585 [inline] #0: ffffffff8bca5140 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4609 [inline] #0: ffffffff8bca5140 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath.constprop.0+0x760/0x21b0 mm/page_alloc.c:5007 1 lock held by systemd-udevd/3061: #0: ffff888102e82d70 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:838 [inline] #0: ffff888102e82d70 (mapping.invalidate_lock){++++}-{3:3}, at: page_cache_ra_unbounded+0x1bc/0x950 mm/readahead.c:194 1 lock held by sd-resolve/3126: #0: ffff88801bc99980 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:838 [inline] #0: ffff88801bc99980 (mapping.invalidate_lock){++++}-{3:3}, at: page_cache_ra_unbounded+0x1bc/0x950 mm/readahead.c:194 1 lock held by cron/6288: #0: ffff88811bdd35c8 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:793 [inline] #0: ffff88811bdd35c8 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: lookup_slow fs/namei.c:1673 [inline] #0: ffff88811bdd35c8 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: walk_component+0x400/0x6a0 fs/namei.c:1970 1 lock held by in:imklog/6757: #0: ffff88801bca6940 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:838 [inline] #0: ffff88801bca6940 (mapping.invalidate_lock){++++}-{3:3}, at: page_cache_ra_unbounded+0x1bc/0x950 mm/readahead.c:194 3 locks held by rs:main Q:Reg/6758: #0: ffff8880158d14f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:1034 #1: ffff88810138a460 (sb_writers#5){.+.+}-{0:0}, at: ksys_write+0x12d/0x250 fs/read_write.c:643 #2: ffff8881104db5c8 (&sb->s_type->i_mutex_key#10){++++}-{3:3}, at: inode_lock include/linux/fs.h:783 [inline] #2: ffff8881104db5c8 (&sb->s_type->i_mutex_key#10){++++}-{3:3}, at: ext4_buffered_write_iter+0xb8/0x360 fs/ext4/file.c:263 1 lock held by syz-fuzzer/6681: #0: ffff8881104c9980 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:838 [inline] #0: ffff8881104c9980 (mapping.invalidate_lock){++++}-{3:3}, at: page_cache_ra_unbounded+0x1bc/0x950 mm/readahead.c:194 1 lock held by syz-fuzzer/6705: #0: ffff8881104c9980 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:838 [inline] #0: ffff8881104c9980 (mapping.invalidate_lock){++++}-{3:3}, at: page_cache_ra_unbounded+0x1bc/0x950 mm/readahead.c:194 1 lock held by syz-fuzzer/6776: #0: ffff8881104c9980 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:838 [inline] #0: ffff8881104c9980 (mapping.invalidate_lock){++++}-{3:3}, at: page_cache_ra_unbounded+0x1bc/0x950 mm/readahead.c:194 1 lock held by syz-executor.7/6790: #0: ffff8881104ca430 (&mapping->i_mmap_rwsem){++++}-{3:3}, at: i_mmap_lock_write include/linux/fs.h:498 [inline] #0: ffff8881104ca430 (&mapping->i_mmap_rwsem){++++}-{3:3}, at: unlink_file_vma+0x7d/0x110 mm/mmap.c:169 2 locks held by kworker/u8:2/7091: 4 locks held by kworker/u8:6/10810: #0: ffff8881000ad938 ((wq_completion)netns){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881000ad938 ((wq_completion)netns){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff8881000ad938 ((wq_completion)netns){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline] #0: ffff8881000ad938 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline] #0: ffff8881000ad938 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline] #0: ffff8881000ad938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x8c3/0x16d0 kernel/workqueue.c:2269 #1: ffffc9000679fdc8 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x8f7/0x16d0 kernel/workqueue.c:2273 #2: ffffffff8d2eeb90 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xa90 net/core/net_namespace.c:555 #3: ffffffff8bb89e70 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x44/0x430 kernel/rcu/tree.c:3985 1 lock held by syz-executor.1/13578: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.1/13694: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.3/18956: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.3/19004: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.3/19028: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.0/20801: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.0/20838: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.3/24608: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.3/24792: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.3/25080: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.3/28598: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.3/28694: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.3/28793: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.0/30370: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.0/30514: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.3/2238: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.3/2357: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.3/2551: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 2 locks held by kworker/3:67/2705: 1 lock held by syz-executor.0/2885: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 7 locks held by kworker/u10:22/3012: #0: ffff888013998138 ((wq_completion)writeback){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888013998138 ((wq_completion)writeback){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff888013998138 ((wq_completion)writeback){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline] #0: ffff888013998138 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline] #0: ffff888013998138 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline] #0: ffff888013998138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x8c3/0x16d0 kernel/workqueue.c:2269 #1: ffffc900149cfdc8 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x8f7/0x16d0 kernel/workqueue.c:2273 #2: ffff88810138a0e0 (&type->s_umount_key#36){++++}-{3:3}, at: trylock_super+0x1d/0x100 fs/super.c:418 #3: ffff88810138cbd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x19b/0x610 mm/page-writeback.c:2364 #4: ffff88810138e990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xf58/0x1360 fs/jbd2/transaction.c:466 #5: ffff8881104db450 (&ei->i_data_sem){++++}-{3:3}, at: ext4_map_blocks+0x5e1/0x17d0 fs/ext4/inode.c:630 #6: ffff8881104ca430 (&mapping->i_mmap_rwsem){++++}-{3:3}, at: i_mmap_lock_read include/linux/fs.h:513 [inline] #6: ffff8881104ca430 (&mapping->i_mmap_rwsem){++++}-{3:3}, at: rmap_walk_file+0x86d/0xc20 mm/rmap.c:2345 1 lock held by syz-executor.7/3492: #0: ffff8880221a2478 (&anon_vma->rwsem){++++}-{3:3}, at: lock_anon_vma_root mm/rmap.c:246 [inline] #0: ffff8880221a2478 (&anon_vma->rwsem){++++}-{3:3}, at: unlink_anon_vmas+0x1fb/0x850 mm/rmap.c:402 1 lock held by syz-executor.1/4126: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.1/4151: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.1/4278: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.3/4358: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 1 lock held by syz-executor.3/4432: #0: ffff88810138a650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x5a0 fs/inode.c:590 Best Regards, Yiru
