Hello, syzbot found the following issue on: HEAD commit: fdf0eaf11452 Linux 6.5-rc2 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=135aae66a80000 kernel config: https://syzkaller.appspot.com/x/.config?x=a4507c291b5ab5d4 dashboard link: https://syzkaller.appspot.com/bug?extid=da4f9f61f96525c62cc7 compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/f95d243908cc/disk-fdf0eaf1.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/f55beab9d6de/vmlinux-fdf0eaf1.xz kernel image: https://storage.googleapis.com/syzbot-assets/bea743a43c4f/bzImage-fdf0eaf1.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+da4f9f61f96525c62cc7@xxxxxxxxxxxxxxxxxxxxxxxxx ====================================================== WARNING: possible circular locking dependency detected 6.5.0-rc2-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/14284 is trying to acquire lock: ffff8880870e9c30 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xb2/0xd10 fs/seq_file.c:182 but task is already holding lock: ffff88814bdc8410 (sb_writers#4){.+.+}-{0:0}, at: do_sendfile+0x600/0x1070 fs/read_write.c:1253 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (sb_writers#4){.+.+}-{0:0}: percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1494 [inline] sb_start_write+0x4d/0x1c0 include/linux/fs.h:1569 mnt_want_write+0x3f/0x90 fs/namespace.c:403 ovl_create_object+0xf8/0x300 fs/overlayfs/dir.c:629 lookup_open fs/namei.c:3492 [inline] open_last_lookups fs/namei.c:3560 [inline] path_openat+0x13e7/0x3180 fs/namei.c:3790 do_filp_open+0x234/0x490 fs/namei.c:3820 do_sys_openat2+0x13e/0x1d0 fs/open.c:1407 do_sys_open fs/open.c:1422 [inline] __do_sys_openat fs/open.c:1438 [inline] __se_sys_openat fs/open.c:1433 [inline] __x64_sys_openat+0x247/0x290 fs/open.c:1433 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #2 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}: down_read+0x47/0x2f0 kernel/locking/rwsem.c:1520 inode_lock_shared include/linux/fs.h:781 [inline] lookup_slow+0x45/0x70 fs/namei.c:1706 walk_component+0x2d0/0x400 fs/namei.c:1998 lookup_last fs/namei.c:2455 [inline] path_lookupat+0x16f/0x450 fs/namei.c:2479 filename_lookup+0x255/0x610 fs/namei.c:2508 kern_path+0x3b/0x180 fs/namei.c:2606 lookup_bdev+0xc5/0x290 block/bdev.c:943 resume_store+0x19c/0x700 kernel/power/hibernate.c:1177 kernfs_fop_write_iter+0x3a6/0x4f0 fs/kernfs/file.c:334 call_write_iter include/linux/fs.h:1871 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x782/0xaf0 fs/read_write.c:584 ksys_write+0x1a0/0x2c0 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #1 (&of->mutex){+.+.}-{3:3}: __mutex_lock_common+0x1d8/0x2530 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x1b/0x20 kernel/locking/mutex.c:799 kernfs_seq_start+0x53/0x3a0 fs/kernfs/file.c:154 seq_read_iter+0x3d4/0xd10 fs/seq_file.c:225 call_read_iter include/linux/fs.h:1865 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x795/0xb00 fs/read_write.c:470 ksys_read+0x1a0/0x2c0 fs/read_write.c:613 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #0 (&p->lock){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3142 [inline] check_prevs_add kernel/locking/lockdep.c:3261 [inline] validate_chain kernel/locking/lockdep.c:3876 [inline] __lock_acquire+0x39ff/0x7f70 kernel/locking/lockdep.c:5144 lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5761 __mutex_lock_common+0x1d8/0x2530 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x1b/0x20 kernel/locking/mutex.c:799 seq_read_iter+0xb2/0xd10 fs/seq_file.c:182 proc_reg_read_iter+0x1bc/0x290 fs/proc/inode.c:305 call_read_iter include/linux/fs.h:1865 [inline] copy_splice_read+0x4c9/0x9c0 fs/splice.c:367 splice_direct_to_actor+0x2c4/0x9e0 fs/splice.c:1070 do_splice_direct+0x2ac/0x3f0 fs/splice.c:1195 do_sendfile+0x623/0x1070 fs/read_write.c:1254 __do_sys_sendfile64 fs/read_write.c:1322 [inline] __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1308 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd other info that might help us debug this: Chain exists of: &p->lock --> &ovl_i_mutex_dir_key[depth] --> sb_writers#4 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(sb_writers#4); lock(&ovl_i_mutex_dir_key[depth]); lock(sb_writers#4); lock(&p->lock); *** DEADLOCK *** 1 lock held by syz-executor.0/14284: #0: ffff88814bdc8410 (sb_writers#4){.+.+}-{0:0}, at: do_sendfile+0x600/0x1070 fs/read_write.c:1253 stack backtrace: CPU: 1 PID: 14284 Comm: syz-executor.0 Not tainted 6.5.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/03/2023 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106 check_noncircular+0x375/0x4a0 kernel/locking/lockdep.c:2195 check_prev_add kernel/locking/lockdep.c:3142 [inline] check_prevs_add kernel/locking/lockdep.c:3261 [inline] validate_chain kernel/locking/lockdep.c:3876 [inline] __lock_acquire+0x39ff/0x7f70 kernel/locking/lockdep.c:5144 lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5761 __mutex_lock_common+0x1d8/0x2530 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x1b/0x20 kernel/locking/mutex.c:799 seq_read_iter+0xb2/0xd10 fs/seq_file.c:182 proc_reg_read_iter+0x1bc/0x290 fs/proc/inode.c:305 call_read_iter include/linux/fs.h:1865 [inline] copy_splice_read+0x4c9/0x9c0 fs/splice.c:367 splice_direct_to_actor+0x2c4/0x9e0 fs/splice.c:1070 do_splice_direct+0x2ac/0x3f0 fs/splice.c:1195 do_sendfile+0x623/0x1070 fs/read_write.c:1254 __do_sys_sendfile64 fs/read_write.c:1322 [inline] __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1308 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fed17a7cb29 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fed188640c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007fed17b9c1f0 RCX: 00007fed17a7cb29 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 0000000000000008 RBP: 00007fed17ac847a R08: 0000000000000000 R09: 0000000000000000 R10: 4000000000010046 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007fed17b9c1f0 R15: 00007fff433e8a98 </TASK> --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the bug is already fixed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to change bug's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the bug is a duplicate of another bug, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
