Hello, syzbot found the following issue on: HEAD commit: c75962170e49 Add linux-next specific files for 20240517 git tree: linux-next console+strace: https://syzkaller.appspot.com/x/log.txt?x=1438a5cc980000 kernel config: https://syzkaller.appspot.com/x/.config?x=fba88766130220e8 dashboard link: https://syzkaller.appspot.com/bug?extid=85e58cdf5b3136471d4b compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=115f3e58980000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14f4c97c980000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/21696f8048a3/disk-c7596217.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/b8c71f928633/vmlinux-c7596217.xz kernel image: https://storage.googleapis.com/syzbot-assets/350bfc6c0a6a/bzImage-c7596217.xz mounted in repro: https://storage.googleapis.com/syzbot-assets/7f6a8434331c/mount_0.gz The issue was bisected to: commit 9a87907de3597a339cc129229d1a20bc7365ea5f Author: Miklos Szeredi <mszeredi@xxxxxxxxxx> Date: Thu May 2 18:35:57 2024 +0000 ovl: implement tmpfile bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=120f89cc980000 final oops: https://syzkaller.appspot.com/x/report.txt?x=110f89cc980000 console output: https://syzkaller.appspot.com/x/log.txt?x=160f89cc980000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+85e58cdf5b3136471d4b@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 9a87907de359 ("ovl: implement tmpfile") ============================================ WARNING: possible recursive locking detected 6.9.0-next-20240517-syzkaller #0 Not tainted -------------------------------------------- syz-executor489/5091 is trying to acquire lock: ffff88802f7f2420 (sb_writers#4){.+.+}-{0:0}, at: ovl_do_copy_up fs/overlayfs/copy_up.c:967 [inline] ffff88802f7f2420 (sb_writers#4){.+.+}-{0:0}, at: ovl_copy_up_one fs/overlayfs/copy_up.c:1168 [inline] ffff88802f7f2420 (sb_writers#4){.+.+}-{0:0}, at: ovl_copy_up_flags+0x1110/0x4470 fs/overlayfs/copy_up.c:1223 but task is already holding lock: ffff88802f7f2420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:409 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(sb_writers#4); lock(sb_writers#4); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by syz-executor489/5091: #0: ffff8880241fe420 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:409 #1: ffff88802f7f2420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:409 #2: ffff88807f0ea808 (&ovl_i_lock_key[depth]){+.+.}-{3:3}, at: ovl_inode_lock_interruptible fs/overlayfs/overlayfs.h:657 [inline] #2: ffff88807f0ea808 (&ovl_i_lock_key[depth]){+.+.}-{3:3}, at: ovl_copy_up_start+0x53/0x310 fs/overlayfs/util.c:719 stack backtrace: CPU: 1 PID: 5091 Comm: syz-executor489 Not tainted 6.9.0-next-20240517-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain+0x15c1/0x58e0 kernel/locking/lockdep.c:3856 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1655 [inline] sb_start_write include/linux/fs.h:1791 [inline] ovl_start_write+0x11d/0x290 fs/overlayfs/util.c:31 ovl_do_copy_up fs/overlayfs/copy_up.c:967 [inline] ovl_copy_up_one fs/overlayfs/copy_up.c:1168 [inline] ovl_copy_up_flags+0x1110/0x4470 fs/overlayfs/copy_up.c:1223 ovl_create_tmpfile fs/overlayfs/dir.c:1317 [inline] ovl_tmpfile+0x262/0x6d0 fs/overlayfs/dir.c:1373 vfs_tmpfile+0x396/0x510 fs/namei.c:3701 do_tmpfile+0x156/0x340 fs/namei.c:3764 path_openat+0x2ab8/0x3280 fs/namei.c:3798 do_filp_open+0x235/0x490 fs/namei.c:3834 do_sys_openat2+0x13e/0x1d0 fs/open.c:1405 do_sys_open fs/open.c:1420 [inline] __do_sys_open fs/open.c:1428 [inline] __se_sys_open fs/open.c:1424 [inline] __x64_sys_open+0x225/0x270 fs/open.c:1424 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fab92feaba9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 17 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd714aed18 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 00007fab92feaba9 RDX: 0000000000000000 RSI: 0000000000410202 RDI: 0000000020000040 RBP: 00007fab930635f0 R08: 000055557e7894c0 R09: 000055557e7894c0 R10: 000055557e7894c0 R11: 0000000000000246 R12: 00007ffd714aed40 R13: 00007ffd714aef68 R14: 431bde82d7b634db R15: 00007fab9303303b </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. For information about bisection process see: https://goo.gl/tpsmEJ#bisection If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
