loop2: detected capacity change from 0 to 2048 EXT4-fs (loop2): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none. ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.2.12686/31969 is trying to acquire lock: ffff0000dd945e80 (&ei->xattr_sem){++++}-{4:4}, at: ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline] ffff0000dd945e80 (&ei->xattr_sem){++++}-{4:4}, at: ext4_destroy_inline_data+0x30/0x114 fs/ext4/inline.c:1805 but task is already holding lock: ffff0000f3180c18 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: percpu_down_read include/linux/percpu-rwsem.h:77 [inline] ffff0000f3180c18 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1811 [inline] ffff0000f3180c18 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x16c/0x2d8 fs/ext4/inode.c:3041 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&sbi->s_writepages_rwsem){++++}-{0:0}: percpu_down_read_internal+0x5c/0x294 include/linux/percpu-rwsem.h:53 percpu_down_read include/linux/percpu-rwsem.h:77 [inline] ext4_writepages_down_read fs/ext4/ext4.h:1811 [inline] ext4_writepages+0x16c/0x2d8 fs/ext4/inode.c:3041 do_writepages+0x270/0x468 mm/page-writeback.c:2575 __writeback_single_inode+0x144/0x1808 fs/fs-writeback.c:1764 writeback_single_inode+0x3b8/0xaa0 fs/fs-writeback.c:1883 write_inode_now+0x170/0x208 fs/fs-writeback.c:2974 iput_final fs/inode.c:1950 [inline] iput+0x6bc/0xb90 fs/inode.c:2009 ext4_xattr_block_set+0x12dc/0x2188 fs/ext4/xattr.c:2206 ext4_xattr_move_to_block fs/ext4/xattr.c:2671 [inline] ext4_xattr_make_inode_space fs/ext4/xattr.c:2746 [inline] ext4_expand_extra_isize_ea+0xb18/0x13a0 fs/ext4/xattr.c:2834 __ext4_expand_extra_isize+0x29c/0x370 fs/ext4/inode.c:6434 ext4_try_to_expand_extra_isize fs/ext4/inode.c:6477 [inline] __ext4_mark_inode_dirty+0x3a4/0x810 fs/ext4/inode.c:6555 ext4_evict_inode+0x7a0/0xfc4 fs/ext4/inode.c:267 evict+0x4b8/0x740 fs/inode.c:841 iput_final fs/inode.c:1960 [inline] iput+0x858/0xb90 fs/inode.c:2009 ext4_process_orphan+0x240/0x2b4 fs/ext4/orphan.c:358 ext4_orphan_cleanup+0x7b8/0xd30 fs/ext4/orphan.c:472 __ext4_fill_super fs/ext4/super.c:5701 [inline] ext4_fill_super+0x45a4/0x4d60 fs/ext4/super.c:5824 get_tree_bdev_flags+0x380/0x434 fs/super.c:1694 get_tree_bdev+0x2c/0x3c fs/super.c:1717 ext4_get_tree+0x28/0x38 fs/ext4/super.c:5856 vfs_get_tree+0x90/0x28c fs/super.c:1754 fc_mount+0x24/0xac fs/namespace.c:1193 do_new_mount_fc fs/namespace.c:3758 [inline] do_new_mount+0x2a4/0x540 fs/namespace.c:3834 path_mount+0x5d0/0xa68 fs/namespace.c:4154 do_mount+0xe8/0x148 fs/namespace.c:4167 __do_sys_mount fs/namespace.c:4383 [inline] __se_sys_mount fs/namespace.c:4360 [inline] __arm64_sys_mount+0x334/0x380 fs/namespace.c:4360 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x60/0x25c arch/arm64/kernel/entry-common.c:723 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:742 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 -> #0 (&ei->xattr_sem){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1780/0x2f44 kernel/locking/lockdep.c:5237 lock_acquire+0x140/0x368 kernel/locking/lockdep.c:5868 down_write+0x50/0xc0 kernel/locking/rwsem.c:1625 ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline] ext4_destroy_inline_data+0x30/0x114 fs/ext4/inline.c:1805 ext4_do_writepages+0x474/0x3ac8 fs/ext4/inode.c:2827 ext4_writepages+0x194/0x2d8 fs/ext4/inode.c:3042 do_writepages+0x270/0x468 mm/page-writeback.c:2575 filemap_writeback+0x230/0x2bc mm/filemap.c:388 filemap_fdatawrite_range mm/filemap.c:413 [inline] file_write_and_wait_range+0xb0/0x138 mm/filemap.c:787 mmb_fsync_noflush+0x80/0x1bc fs/buffer.c:645 ext4_fsync_nojournal fs/ext4/fsync.c:92 [inline] ext4_sync_file+0x36c/0xef0 fs/ext4/fsync.c:160 vfs_fsync_range+0x120/0x140 fs/sync.c:186 generic_write_sync include/linux/fs.h:2654 [inline] ext4_buffered_write_iter+0x24c/0x310 fs/ext4/file.c:322 ext4_file_write_iter+0x1d8/0x1390 fs/ext4/file.c:-1 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x52c/0xa14 fs/read_write.c:688 ksys_pwrite64+0x118/0x1b0 fs/read_write.c:795 __do_sys_pwrite64 fs/read_write.c:803 [inline] __se_sys_pwrite64 fs/read_write.c:800 [inline] __arm64_sys_pwrite64+0x9c/0xb4 fs/read_write.c:800 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x60/0x25c arch/arm64/kernel/entry-common.c:723 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:742 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(&sbi->s_writepages_rwsem); lock(&ei->xattr_sem); lock(&sbi->s_writepages_rwsem); lock(&ei->xattr_sem); *** DEADLOCK *** 2 locks held by syz.2.12686/31969: #0: ffff0000d77c4410 (sb_writers#3){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2724 [inline] #0: ffff0000d77c4410 (sb_writers#3){.+.+}-{0:0}, at: vfs_write+0x240/0xa14 fs/read_write.c:684 #1: ffff0000f3180c18 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: percpu_down_read include/linux/percpu-rwsem.h:77 [inline] #1: ffff0000f3180c18 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1811 [inline] #1: ffff0000f3180c18 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x16c/0x2d8 fs/ext4/inode.c:3041 stack backtrace: CPU: 1 UID: 0 PID: 31969 Comm: syz.2.12686 Tainted: G L syzkaller #0 PREEMPT Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x328/0x330 kernel/locking/lockdep.c:2043 check_noncircular+0x158/0x174 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1780/0x2f44 kernel/locking/lockdep.c:5237 lock_acquire+0x140/0x368 kernel/locking/lockdep.c:5868 down_write+0x50/0xc0 kernel/locking/rwsem.c:1625 ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline] ext4_destroy_inline_data+0x30/0x114 fs/ext4/inline.c:1805 ext4_do_writepages+0x474/0x3ac8 fs/ext4/inode.c:2827 ext4_writepages+0x194/0x2d8 fs/ext4/inode.c:3042 do_writepages+0x270/0x468 mm/page-writeback.c:2575 filemap_writeback+0x230/0x2bc mm/filemap.c:388 filemap_fdatawrite_range mm/filemap.c:413 [inline] file_write_and_wait_range+0xb0/0x138 mm/filemap.c:787 mmb_fsync_noflush+0x80/0x1bc fs/buffer.c:645 ext4_fsync_nojournal fs/ext4/fsync.c:92 [inline] ext4_sync_file+0x36c/0xef0 fs/ext4/fsync.c:160 vfs_fsync_range+0x120/0x140 fs/sync.c:186 generic_write_sync include/linux/fs.h:2654 [inline] ext4_buffered_write_iter+0x24c/0x310 fs/ext4/file.c:322 ext4_file_write_iter+0x1d8/0x1390 fs/ext4/file.c:-1 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x52c/0xa14 fs/read_write.c:688 ksys_pwrite64+0x118/0x1b0 fs/read_write.c:795 __do_sys_pwrite64 fs/read_write.c:803 [inline] __se_sys_pwrite64 fs/read_write.c:800 [inline] __arm64_sys_pwrite64+0x9c/0xb4 fs/read_write.c:800 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x60/0x25c arch/arm64/kernel/entry-common.c:723 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:742 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 EXT4-fs error (device loop2): ext4_mb_generate_buddy:1317: group 0, block bitmap and bg descriptor inconsistent: 25 vs 150994969 free clusters EXT4-fs (loop2): Delayed block allocation failed for inode 15 at logical offset 31 with max blocks 33 with error 28 EXT4-fs (loop2): This should not happen!! Data will be lost EXT4-fs (loop2): Total free blocks count 0 EXT4-fs (loop2): Free/Dirty block details EXT4-fs (loop2): free_blocks=2415919104 EXT4-fs (loop2): dirty_blocks=64 EXT4-fs (loop2): Block reservation details EXT4-fs (loop2): i_reserved_data_blocks=4