====================================================== WARNING: possible circular locking dependency detected 6.6.101-syzkaller #0 Not tainted ------------------------------------------------------ syz.3.496/8283 is trying to acquire lock: ffff88814dbc40e0 (&type->s_umount_key#31){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline] ffff88814dbc40e0 (&type->s_umount_key#31){++++}-{3:3}, at: super_lock+0x167/0x360 fs/super.c:117 but task is already holding lock: ffff888148ca1808 (&bdev->bd_holder_lock){+.+.}-{3:3}, at: blkdev_flushbuf block/ioctl.c:373 [inline] ffff888148ca1808 (&bdev->bd_holder_lock){+.+.}-{3:3}, at: blkdev_common_ioctl+0x814/0x23d0 block/ioctl.c:505 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&bdev->bd_holder_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x129/0xcc0 kernel/locking/mutex.c:747 bd_finish_claiming+0x22f/0x3f0 block/bdev.c:568 blkdev_get_by_dev+0x45c/0x600 block/bdev.c:801 bdev_open_by_dev+0x77/0x100 block/bdev.c:842 setup_bdev_super+0x59/0x660 fs/super.c:1496 mount_bdev+0x1dd/0x2d0 fs/super.c:1640 legacy_get_tree+0xea/0x180 fs/fs_context.c:662 vfs_get_tree+0x8c/0x280 fs/super.c:1764 do_new_mount+0x24b/0xa40 fs/namespace.c:3371 init_mount+0xd2/0x120 fs/init.c:25 do_mount_root+0x97/0x230 init/do_mounts.c:166 mount_root_generic+0x195/0x3c0 init/do_mounts.c:205 prepare_namespace+0xc2/0x100 init/do_mounts.c:489 kernel_init_freeable+0x413/0x570 init/main.c:1566 kernel_init+0x1d/0x1c0 init/main.c:1443 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 -> #3 (bdev_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x129/0xcc0 kernel/locking/mutex.c:747 bd_prepare_to_claim+0x1ba/0x480 block/bdev.c:510 truncate_bdev_range+0x4e/0x260 block/bdev.c:105 blkdev_fallocate+0x4e0/0x670 block/fops.c:783 vfs_fallocate+0x58e/0x700 fs/open.c:324 ksys_fallocate fs/open.c:347 [inline] __do_sys_fallocate fs/open.c:355 [inline] __se_sys_fallocate fs/open.c:353 [inline] __x64_sys_fallocate+0xc1/0x110 fs/open.c:353 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #2 (mapping.invalidate_lock#2){++++}-{3:3}: down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520 filemap_invalidate_lock_shared include/linux/fs.h:859 [inline] filemap_fault+0x5db/0x15a0 mm/filemap.c:3330 __do_fault+0x13b/0x4e0 mm/memory.c:4243 do_read_fault mm/memory.c:4616 [inline] do_fault mm/memory.c:4753 [inline] do_pte_missing mm/memory.c:3688 [inline] handle_pte_fault mm/memory.c:5025 [inline] __handle_mm_fault mm/memory.c:5166 [inline] handle_mm_fault+0x3886/0x4920 mm/memory.c:5331 faultin_page mm/gup.c:868 [inline] __get_user_pages+0x5ea/0x1470 mm/gup.c:1167 populate_vma_page_range+0x2b6/0x370 mm/gup.c:1593 __mm_populate+0x24c/0x380 mm/gup.c:1696 mm_populate include/linux/mm.h:3317 [inline] vm_mmap_pgoff+0x2e7/0x400 mm/util.c:561 ksys_mmap_pgoff+0x520/0x700 mm/mmap.c:1427 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #1 (&mm->mmap_lock){++++}-{3:3}: __might_fault+0xc6/0x120 mm/memory.c:5946 _copy_from_user+0x2a/0xe0 lib/usercopy.c:14 copy_from_user include/linux/uaccess.h:183 [inline] quota_setquota+0x115/0x530 fs/quota/quota.c:301 __do_sys_quotactl fs/quota/quota.c:961 [inline] __se_sys_quotactl+0x27b/0x950 fs/quota/quota.c:917 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (&type->s_umount_key#31){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520 __super_lock fs/super.c:58 [inline] super_lock+0x167/0x360 fs/super.c:117 super_lock_shared fs/super.c:146 [inline] super_lock_shared_active fs/super.c:1442 [inline] fs_bdev_sync+0xa4/0x170 fs/super.c:1477 blkdev_flushbuf block/ioctl.c:375 [inline] blkdev_common_ioctl+0x880/0x23d0 block/ioctl.c:505 blkdev_ioctl+0x4eb/0x6f0 block/ioctl.c:627 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 other info that might help us debug this: Chain exists of: &type->s_umount_key#31 --> bdev_lock --> &bdev->bd_holder_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&bdev->bd_holder_lock); lock(bdev_lock); lock(&bdev->bd_holder_lock); rlock(&type->s_umount_key#31); *** DEADLOCK *** 1 lock held by syz.3.496/8283: #0: ffff888148ca1808 (&bdev->bd_holder_lock){+.+.}-{3:3}, at: blkdev_flushbuf block/ioctl.c:373 [inline] #0: ffff888148ca1808 (&bdev->bd_holder_lock){+.+.}-{3:3}, at: blkdev_common_ioctl+0x814/0x23d0 block/ioctl.c:505 stack backtrace: CPU: 1 PID: 8283 Comm: syz.3.496 Not tainted 6.6.101-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 check_noncircular+0x2bd/0x3c0 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520 __super_lock fs/super.c:58 [inline] super_lock+0x167/0x360 fs/super.c:117 super_lock_shared fs/super.c:146 [inline] super_lock_shared_active fs/super.c:1442 [inline] fs_bdev_sync+0xa4/0x170 fs/super.c:1477 blkdev_flushbuf block/ioctl.c:375 [inline] blkdev_common_ioctl+0x880/0x23d0 block/ioctl.c:505 blkdev_ioctl+0x4eb/0x6f0 block/ioctl.c:627 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fdc2db8eb69 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fdc2ea21038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fdc2ddb5fa0 RCX: 00007fdc2db8eb69 RDX: 0000000000000008 RSI: 0000000000001261 RDI: 0000000000000004 RBP: 00007fdc2dc11df1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fdc2ddb5fa0 R15: 00007ffcff264ca8