====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.4.943/10134 is trying to acquire lock: ffff0000d9059460 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock+0x68/0x98 fs/pipe.c:91 but task is already holding lock: ffff0000dbd28410 (sb_writers#5){.+.+}-{0:0}, at: do_splice+0x93c/0x1214 fs/splice.c:1348 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (sb_writers#5){.+.+}-{0:0}: percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline] percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline] __sb_start_write include/linux/fs/super.h:19 [inline] sb_start_write+0x5c/0x294 include/linux/fs/super.h:125 mnt_want_write+0x44/0x9c fs/namespace.c:493 ovl_want_write+0x90/0xa0 fs/overlayfs/util.c:38 ovl_rename_start fs/overlayfs/dir.c:1198 [inline] ovl_rename+0x430/0xfec fs/overlayfs/dir.c:1363 vfs_rename+0xa78/0xd48 fs/namei.c:6054 filename_renameat2+0x66c/0x730 fs/namei.c:6172 __do_sys_renameat2 fs/namei.c:6201 [inline] __se_sys_renameat2 fs/namei.c:6196 [inline] __arm64_sys_renameat2+0xe4/0x114 fs/namei.c:6196 __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+0x64/0x260 arch/arm64/kernel/entry-common.c:740 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:759 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 -> #2 (&ovl_i_mutex_key[depth]/4){+.+.}-{4:4}: down_write_nested+0x58/0xcc kernel/locking/rwsem.c:1751 inode_lock_nested include/linux/fs.h:1074 [inline] lock_two_nondirectories+0xe8/0x148 fs/inode.c:1256 ext4_move_extents+0x194/0x3580 fs/ext4/move_extent.c:589 __ext4_ioctl fs/ext4/ioctl.c:1657 [inline] ext4_ioctl+0x2a14/0x4234 fs/ext4/ioctl.c:1922 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:583 __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+0x64/0x260 arch/arm64/kernel/entry-common.c:740 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:759 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 -> #1 (&sb->s_type->i_mutex_key#10){++++}-{4:4}: down_read+0x58/0x2bc kernel/locking/rwsem.c:1568 inode_lock_shared include/linux/fs.h:1044 [inline] ext4_dio_read_iter fs/ext4/file.c:78 [inline] ext4_file_read_iter+0x19c/0x42c fs/ext4/file.c:145 copy_splice_read+0x4b4/0x8d0 fs/splice.c:362 do_splice_read+0x1f4/0x2e0 fs/splice.c:979 splice_file_to_pipe+0x84/0xd4 fs/splice.c:1290 do_sendfile+0x398/0x68c fs/read_write.c:1378 __do_sys_sendfile64 fs/read_write.c:1433 [inline] __se_sys_sendfile64 fs/read_write.c:1419 [inline] __arm64_sys_sendfile64+0x1b8/0x280 fs/read_write.c:1419 __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+0x64/0x260 arch/arm64/kernel/entry-common.c:740 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:759 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 -> #0 (&pipe->mutex){+.+.}-{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 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x160/0xef8 kernel/locking/mutex.c:820 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:873 pipe_lock+0x68/0x98 fs/pipe.c:91 iter_file_splice_write+0x188/0xd3c fs/splice.c:682 do_splice_from fs/splice.c:936 [inline] do_splice+0x9a0/0x1214 fs/splice.c:1349 __do_splice fs/splice.c:1431 [inline] __do_sys_splice fs/splice.c:1634 [inline] __se_sys_splice fs/splice.c:1616 [inline] __arm64_sys_splice+0x2b4/0x4e0 fs/splice.c:1616 __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+0x64/0x260 arch/arm64/kernel/entry-common.c:740 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:759 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 other info that might help us debug this: Chain exists of: &pipe->mutex --> &ovl_i_mutex_key[depth]/4 --> sb_writers#5 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(sb_writers#5); lock(&ovl_i_mutex_key[depth]/4); lock(sb_writers#5); lock(&pipe->mutex); *** DEADLOCK *** 1 lock held by syz.4.943/10134: #0: ffff0000dbd28410 (sb_writers#5){.+.+}-{0:0}, at: do_splice+0x93c/0x1214 fs/splice.c:1348 stack backtrace: CPU: 0 UID: 0 PID: 10134 Comm: syz.4.943 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 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x160/0xef8 kernel/locking/mutex.c:820 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:873 pipe_lock+0x68/0x98 fs/pipe.c:91 iter_file_splice_write+0x188/0xd3c fs/splice.c:682 do_splice_from fs/splice.c:936 [inline] do_splice+0x9a0/0x1214 fs/splice.c:1349 __do_splice fs/splice.c:1431 [inline] __do_sys_splice fs/splice.c:1634 [inline] __se_sys_splice fs/splice.c:1616 [inline] __arm64_sys_splice+0x2b4/0x4e0 fs/splice.c:1616 __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+0x64/0x260 arch/arm64/kernel/entry-common.c:740 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:759 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594