From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-io1-f77.google.com (mail-io1-f77.google.com [209.85.166.77]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B0DF61DE8A4 for ; Sun, 14 Sep 2025 06:44:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.77 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757832273; cv=none; b=DpGyQolfRbE51H1Z9jgUbpwcNydFN9tfbpqzOpIqo9k4oTlJ2XiM9XjCraHKEjVHUnwZ4ijGAMvxL8ixcAWW2o5ot1abwLYv1zloy67Me/PGHZtEQ6Vc0QDE0XUpgF940P6M3zzng7FvV88KCA5Gs/YGmb9yA6DgLr7o9booZPc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757832273; c=relaxed/simple; bh=jrBUgjlBPg3x+xR9tOFzZ7evCjzU70FLUvMZaPXfLU0=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=q7f1XAHJ36oKexH3JLvuRG56ltIQ3Kxt1qeIuDCLtbvMhpt56IhyQtmyQuMX0n5RVG3p6imgq1uvI0uBCbK5apNxdVTak5EtXgQ6JHBDbow4A5B+7v4Z/LRVKW+ZYoqzMxyHMNl4cg+Y8FMRalJiBEafYjY4f6wlBOE5M4omP5U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.166.77 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-io1-f77.google.com with SMTP id ca18e2360f4ac-889b4288f39so380926539f.1 for ; Sat, 13 Sep 2025 23:44:31 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757832271; x=1758437071; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=jh7N12ZIznXRHjwEs6OTGR6qER4A9V+V4hq5c1+Q5M0=; b=RBLNKshJgU4lIVLCq4KZbrzfVcWXONEapdGT1y+gGdevA9QEnEsjbIvvNG/yimNGDe Q9CVRQN7gyvLB62ZO1EOuFVrUWqitLRocoEeVjpdDt7v16SwTlKj3Bt39mfVWu+BYaQT gvnfnVmUA0xrFit2jqZsP3TIUIoejxHtzdzgenpXzkxFPr/auM+QCUuqQircRTFeiX6B m7ZtI64ZoUdTgnnUmWVlQSBtQRJUyez5vcC3RCB6FAIHDqPIyz7+Kvi8SHZwAcMYVAHy ay4BjLLYnbFkFah5tLQo86+ejt97jGcr9InILTIh7FQioeC000VYqOtwwVU2aws+x48t Y9uA== X-Forwarded-Encrypted: i=1; AJvYcCX1FnxJGfjsI+/MRXOBtUXFz8kZio6SCmub37N3qpS/6ipCGhIhK4aimmbH2issaXaAOqr1CjL5ALXwM7Q=@vger.kernel.org X-Gm-Message-State: AOJu0Yz+h07EkXcZPV393vbi6mvET8LXpyQKZF19OQavPLF3D3vWw1qv 4ggJMaGCj0NIJ/qRpjVHa2Iivw/29bl2PWGdfMsbPaJ7km40FU2ZIuKneni7a4/5xfc8/ufnQpU +z1/j8as8rO5cuA5f+O37I7SqfTeEAxmNA822F6cOo4xxX6em62TmgIN2i8w= X-Google-Smtp-Source: AGHT+IEZ5IhsR463Dw++PpgMh4V7QbV0n/WlF9fEr8a3j/QEwJbAiEqAecsP4HWzjr+0FuuStlJ9F18XBRsBKU6ph9ZeKVYnplpp Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6602:489:b0:887:601:c5f6 with SMTP id ca18e2360f4ac-89029880341mr1131890939f.7.1757832270841; Sat, 13 Sep 2025 23:44:30 -0700 (PDT) Date: Sat, 13 Sep 2025 23:44:30 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <68c6644e.050a0220.50883.0000.GAE@google.com> Subject: [syzbot] [btrfs?] possible deadlock in iterate_dir (3) From: syzbot To: clm@fb.com, dsterba@suse.com, josef@toxicpanda.com, linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 9dd1835ecda5 Merge tag 'dma-mapping-6.17-2025-09-09' of gi.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16d47562580000 kernel config: https://syzkaller.appspot.com/x/.config?x=429771c55b615e85 dashboard link: https://syzkaller.appspot.com/bug?extid=e290013facb5d5159eca compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/63dc392685dc/disk-9dd1835e.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/3dfcfb97806e/vmlinux-9dd1835e.xz kernel image: https://storage.googleapis.com/syzbot-assets/ddb10128aeb8/bzImage-9dd1835e.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+e290013facb5d5159eca@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.2.243/11919 is trying to acquire lock: ffff88803c665110 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:462 but task is already holding lock: ffff8880298fbd68 (&type->i_mutex_dir_key#5){++++}-{4:4}, at: iterate_dir+0x29e/0x580 fs/readdir.c:101 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&type->i_mutex_dir_key#5){++++}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_read+0x97/0x1f0 kernel/locking/rwsem.c:1537 inode_lock_shared include/linux/fs.h:885 [inline] lookup_slow+0x46/0x70 fs/namei.c:1824 walk_component+0x2d2/0x400 fs/namei.c:2129 lookup_last fs/namei.c:2630 [inline] path_lookupat+0x163/0x430 fs/namei.c:2654 filename_lookup+0x212/0x570 fs/namei.c:2683 kern_path+0x35/0x50 fs/namei.c:2816 is_same_device fs/btrfs/volumes.c:759 [inline] device_list_add+0xe2a/0x22a0 fs/btrfs/volumes.c:894 btrfs_scan_one_device+0x3ee/0x650 fs/btrfs/volumes.c:1493 btrfs_get_tree_super fs/btrfs/super.c:1853 [inline] btrfs_get_tree_subvol fs/btrfs/super.c:2077 [inline] btrfs_get_tree+0x433/0x1820 fs/btrfs/super.c:2111 vfs_get_tree+0x8f/0x2b0 fs/super.c:1815 do_new_mount+0x2a2/0x9e0 fs/namespace.c:3808 do_mount fs/namespace.c:4136 [inline] __do_sys_mount fs/namespace.c:4347 [inline] __se_sys_mount+0x317/0x410 fs/namespace.c:4324 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #4 (&fs_devs->device_list_mutex){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/rtmutex_api.c:535 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:547 btrfs_run_dev_stats+0x102/0x10e0 fs/btrfs/volumes.c:7772 commit_cowonly_roots+0x1b2/0x860 fs/btrfs/transaction.c:1348 btrfs_commit_transaction+0xfc7/0x3950 fs/btrfs/transaction.c:2462 sync_filesystem+0x1ce/0x250 fs/sync.c:66 __do_sys_syncfs fs/sync.c:160 [inline] __se_sys_syncfs+0x94/0x110 fs/sync.c:149 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (&fs_info->reloc_mutex){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/rtmutex_api.c:535 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:547 btrfs_commit_transaction+0xedd/0x3950 fs/btrfs/transaction.c:2408 sync_filesystem+0x1ce/0x250 fs/sync.c:66 __do_sys_syncfs fs/sync.c:160 [inline] __se_sys_syncfs+0x94/0x110 fs/sync.c:149 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (btrfs_trans_unblocked){++++}-{0:0}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 wait_current_trans+0x22b/0x520 fs/btrfs/transaction.c:531 start_transaction+0x6d1/0x1620 fs/btrfs/transaction.c:707 btrfs_dirty_inode+0x9f/0x190 fs/btrfs/inode.c:6235 inode_update_time fs/inode.c:2075 [inline] touch_atime+0x2f9/0x6d0 fs/inode.c:2148 file_accessed include/linux/fs.h:2664 [inline] filemap_read+0x100b/0x11a0 mm/filemap.c:2784 __kernel_read+0x4d5/0x970 fs/read_write.c:530 integrity_kernel_read+0x89/0xd0 security/integrity/iint.c:28 ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:480 [inline] ima_calc_file_shash security/integrity/ima/ima_crypto.c:511 [inline] ima_calc_file_hash+0x86a/0x1700 security/integrity/ima/ima_crypto.c:568 ima_collect_measurement+0x42e/0x8e0 security/integrity/ima/ima_api.c:293 process_measurement+0x112d/0x1a40 security/integrity/ima/ima_main.c:405 ima_file_check+0xd7/0x120 security/integrity/ima/ima_main.c:633 security_file_post_open+0xbb/0x290 security/security.c:3160 do_open fs/namei.c:3889 [inline] path_openat+0x2f32/0x3840 fs/namei.c:4046 do_filp_open+0x1fa/0x410 fs/namei.c:4073 do_sys_openat2+0x121/0x1c0 fs/open.c:1435 do_sys_open fs/open.c:1450 [inline] __do_sys_openat fs/open.c:1466 [inline] __se_sys_openat fs/open.c:1461 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1461 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (sb_internal#2){.+.+}-{0:0}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 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.h:1799 [inline] sb_start_intwrite include/linux/fs.h:1982 [inline] start_transaction+0x56e/0x1620 fs/btrfs/transaction.c:699 btrfs_dirty_inode+0x9f/0x190 fs/btrfs/inode.c:6235 inode_update_time fs/inode.c:2075 [inline] touch_atime+0x2f9/0x6d0 fs/inode.c:2148 file_accessed include/linux/fs.h:2664 [inline] btrfs_file_mmap_prepare+0xde/0x150 fs/btrfs/file.c:2050 vfs_mmap_prepare include/linux/fs.h:2295 [inline] call_mmap_prepare mm/vma.c:2585 [inline] __mmap_region mm/vma.c:2653 [inline] mmap_region+0xb49/0x20a0 mm/vma.c:2739 do_mmap+0xc23/0x10c0 mm/mmap.c:558 vm_mmap_pgoff+0x2a9/0x4d0 mm/util.c:580 ksys_mmap_pgoff+0x4e9/0x720 mm/mmap.c:604 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&mm->mmap_lock){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_read_killable+0x9d/0x220 kernel/locking/rwsem.c:1560 mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:462 get_mmap_lock_carefully mm/mmap_lock.c:286 [inline] lock_mm_and_find_vma+0x2a8/0x300 mm/mmap_lock.c:337 do_user_addr_fault+0x331/0x1390 arch/x86/mm/fault.c:1359 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x76/0xf0 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 user_access_begin arch/x86/include/asm/uaccess.h:-1 [inline] filldir+0x2a2/0x6c0 fs/readdir.c:290 dir_emit_dot include/linux/fs.h:3963 [inline] dir_emit_dots include/linux/fs.h:3974 [inline] offset_readdir+0x1e3/0x560 fs/libfs.c:569 iterate_dir+0x3a2/0x580 fs/readdir.c:108 __do_sys_getdents fs/readdir.c:326 [inline] __se_sys_getdents+0xe4/0x250 fs/readdir.c:312 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &mm->mmap_lock --> &fs_devs->device_list_mutex --> &type->i_mutex_dir_key#5 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(&type->i_mutex_dir_key#5); lock(&fs_devs->device_list_mutex); lock(&type->i_mutex_dir_key#5); rlock(&mm->mmap_lock); *** DEADLOCK *** 2 locks held by syz.2.243/11919: #0: ffff8880302b6928 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x253/0x320 fs/file.c:1232 #1: ffff8880298fbd68 (&type->i_mutex_dir_key#5){++++}-{4:4}, at: iterate_dir+0x29e/0x580 fs/readdir.c:101 stack backtrace: CPU: 1 UID: 0 PID: 11919 Comm: syz.2.243 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043 check_noncircular+0x134/0x160 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+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_read_killable+0x9d/0x220 kernel/locking/rwsem.c:1560 mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:462 get_mmap_lock_carefully mm/mmap_lock.c:286 [inline] lock_mm_and_find_vma+0x2a8/0x300 mm/mmap_lock.c:337 do_user_addr_fault+0x331/0x1390 arch/x86/mm/fault.c:1359 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x76/0xf0 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0010:filldir+0x2a2/0x6c0 fs/readdir.c:294 Code: 8f ff 4c 89 ff 4c 89 e6 e8 9b 19 8f ff 4d 39 e7 0f 82 7c 02 00 00 49 39 ef 0f 87 73 02 00 00 0f 01 cb 0f ae e8 48 8b 44 24 50 <49> 89 44 24 08 48 8b 4c 24 08 48 8b 44 24 58 48 89 01 48 8b 04 24 RSP: 0018:ffffc9000c6b7c90 EFLAGS: 00050287 RAX: 0000000000000000 RBX: ffffc9000c6b7e38 RCX: ffff88805b34d940 RDX: 0000000000000000 RSI: 0000200000001fc0 RDI: 0000200000001fd8 RBP: 00007ffffffff000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: ffffffff822f4620 R12: 0000200000001fc0 R13: ffffffff8b191ce0 R14: 0000000000000001 R15: 0000200000001fd8 dir_emit_dot include/linux/fs.h:3963 [inline] dir_emit_dots include/linux/fs.h:3974 [inline] offset_readdir+0x1e3/0x560 fs/libfs.c:569 iterate_dir+0x3a2/0x580 fs/readdir.c:108 __do_sys_getdents fs/readdir.c:326 [inline] __se_sys_getdents+0xe4/0x250 fs/readdir.c:312 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f974ee8eba9 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:00007f9744ccd038 EFLAGS: 00000246 ORIG_RAX: 000000000000004e RAX: ffffffffffffffda RBX: 00007f974f0d6090 RCX: 00007f974ee8eba9 RDX: 00000000000000b8 RSI: 0000200000001fc0 RDI: 0000000000000004 RBP: 00007f974ef11e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f974f0d6128 R14: 00007f974f0d6090 R15: 00007ffce04f3a78 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: ff 4c 89 ff decl -0x1(%rcx,%rcx,4) 4: 4c 89 e6 mov %r12,%rsi 7: e8 9b 19 8f ff call 0xff8f19a7 c: 4d 39 e7 cmp %r12,%r15 f: 0f 82 7c 02 00 00 jb 0x291 15: 49 39 ef cmp %rbp,%r15 18: 0f 87 73 02 00 00 ja 0x291 1e: 0f 01 cb stac 21: 0f ae e8 lfence 24: 48 8b 44 24 50 mov 0x50(%rsp),%rax * 29: 49 89 44 24 08 mov %rax,0x8(%r12) <-- trapping instruction 2e: 48 8b 4c 24 08 mov 0x8(%rsp),%rcx 33: 48 8b 44 24 58 mov 0x58(%rsp),%rax 38: 48 89 01 mov %rax,(%rcx) 3b: 48 8b 04 24 mov (%rsp),%rax --- 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@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title 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