From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oa1-f71.google.com (mail-oa1-f71.google.com [209.85.160.71]) (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 D62F94825A0 for ; Thu, 1 Oct 2026 21:38:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.71 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790890711; cv=none; b=afKNdMEBSWcsRed1iZ8K/iX/lcla81veDkPRMujs9CCfXcFqwTa5lbNu4br+FizxcWZW0PKDLLDcnsArOPqX38jzM92fn/hleAjKFc1r7wHiMudFmjUdwJ1wlhs7BjO9uk5rPLPYP7GPU8RNg8V944lI0OuZN5btr9Jk2cP/K78= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790890711; c=relaxed/simple; bh=/lZxEh665BikeST0L+xJJ/DMpe47LhzV4ONcfDWIfmA=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=iBjyhOwJcjLwD6CPq+VIa1gGPTHpBwe4hvH8smQ44XKyfqd4KoUIBH0WPc7LT2lMnYbCRHZEeVti4L7XWnSs8xKps+c+y1D7nE0ZKfxWGmQV7qIalxuGlDCH8IcR3WLzKD13gzOpcOaCv+5jC6RJPo7w6TRKrrtqcgAxL9BBCKM= 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=209.85.160.71 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-oa1-f71.google.com with SMTP id 586e51a60fabf-49dd7ffb6eeso2732687fac.1 for ; Thu, 01 Oct 2026 14:38:27 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790890706; x=1791495506; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=uST/fJA8PntdH+iehUrW7X8BNz4nkb3lh+gtfS1Ap2U=; b=i5p4xQ4ksyYjBxTO9XRpb35ISw/IkwaxM5hKsgnnbal/Qv4jOKNmCSUe8vYa0gu5sf BTElFs6POKvJIkSHh47WxUipahtPiPcq69qhyX9RoZ17qyZyQ8Uuboi5OMiOgSXOqZKa CjwvRbZxvY4wQ9xTq6rxEJmRtBAbVXBrYfT92eBj3xmwjwKnaczuYkaQcdAnGGY+bXzY iiAwZSn5u6lmO+4wjrC/gXBNFsy0VC0713S6hsEnKHWSlQQOERe9ei9B9EH8t6161v1I kTWQPR0cXbrwq+FYcpcye+81IvMKfW2gNBg89T+4ihwi+M5Z9ZMRj4cQlIx27EpeVzQk UBPw== X-Forwarded-Encrypted: i=1; AKwUvBw2jEBa5H5ly+4HhKqAQzX+fh0yq2BoPX49RNH8YMUG7jReTisTKOIiy2wnLE7XqLxn73yYzdgv4DxMJAA=@vger.kernel.org X-Gm-Message-State: AFuF++msQ0OqEZ0+6Bph6MWUOJhy8gweNtrkwtf78rViRTrqQAlzTXWC WojpHc4/hN84WQBl+80dOdF40Nvlbc1CmPly2yKbscM2UX6/q0hkaTixrWlW8J7LG4EHCbrIqN5 ZXqAO5zx/9PgdXNMae3xIUMKuWitPavdFaZKPm6nXacJicvDDln+EIHcmbQE= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6809:2ca:10b0:4f5:4780:582 with SMTP id 5614622812f47-4f5478f7e75mr118947b6e.50.1790890706629; Thu, 01 Oct 2026 14:38:26 -0700 (PDT) Date: Thu, 01 Oct 2026 14:38:26 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6abed2d2.eb639fcc.2b981.0006.GAE@google.com> Subject: [syzbot] [btrfs?] kernel BUG in btrfs_backref_release_cache (4) From: syzbot To: clm@fb.com, dsterba@suse.com, linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, mason@kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: d266640c6c76 Merge tag 'driver-core-7.3-rc5' of git://git... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16cc3315580000 kernel config: https://syzkaller.appspot.com/x/.config?x=2b924f079099ba6e dashboard link: https://syzkaller.appspot.com/bug?extid=918038c3f9425b05dcd3 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-d266640c.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/25e4cb4d0962/vmlinux-d266640c.xz kernel image: https://storage.googleapis.com/syzbot-assets/ea6eec983242/bzImage-d266640c.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+918038c3f9425b05dcd3@syzkaller.appspotmail.com BTRFS info (device loop0): balance: start -d -m BTRFS info (device loop0): relocating block group 6881280 flags data|metadata BTRFS info (device loop0): relocating block group 5242880 flags data|metadata BTRFS info (device loop0): found 9 extents, stage: move data extents assertion failed: !cache->nr_nodes, in fs/btrfs/backref.c:3163 (cache->nr_nodes=2) ------------[ cut here ]------------ kernel BUG at fs/btrfs/backref.c:3163! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI CPU: 0 UID: 0 PID: 5328 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:btrfs_backref_release_cache+0x1fe/0x230 fs/btrfs/backref.c:3163 Code: 0f 0b e8 75 da 90 fd 48 c7 c7 20 c8 5b 8c 48 c7 c6 80 c8 5b 8c 48 c7 c2 80 bf 5b 8c b9 5b 0c 00 00 41 89 e8 e8 23 9e f0 fc 90 <0f> 0b e8 4b da 90 fd 48 c7 c7 c0 c8 5b 8c 48 c7 c6 20 c9 5b 8c 48 RSP: 0018:ffffc9000eb7f7e8 EFLAGS: 00010246 RAX: 0000000000000052 RBX: ffff88801fa82020 RCX: 980914ae5784ef00 RDX: 0000000000000000 RSI: 8000000000000000 RDI: 0000000000000000 RBP: 0000000000000002 R08: ffffc9000eb7f567 R09: 1ffff92001d6feac R10: dffffc0000000000 R11: fffff52001d6fead R12: dffffc0000000000 R13: 1ffff11003f50404 R14: ffff88801fa820f0 R15: ffff8880525fd3b0 FS: 00007facfea6b6c0(0000) GS:ffff88808c2bc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000001000 CR3: 000000001235c000 CR4: 0000000000352ef0 Call Trace: relocate_block_group+0xb84/0xeb0 fs/btrfs/relocation.c:3756 do_nonremap_reloc+0xa7/0x560 fs/btrfs/relocation.c:5391 btrfs_relocate_block_group+0x6e2/0xaf0 fs/btrfs/relocation.c:5558 btrfs_relocate_chunk+0x114/0x810 fs/btrfs/volumes.c:3729 __btrfs_balance+0x1b5f/0x29d0 fs/btrfs/volumes.c:4668 btrfs_balance+0xaa6/0x1180 fs/btrfs/volumes.c:5055 btrfs_ioctl_balance+0x3da/0x640 fs/btrfs/ioctl.c:3494 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7facfdb9e159 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007facfea6afe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007facfde26090 RCX: 00007facfdb9e159 RDX: 0000200000000180 RSI: 00000000c4009420 RDI: 0000000000000006 RBP: 00007facfdc3506b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007facfde26128 R14: 00007facfde26090 R15: 00007fff41f35e48 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:btrfs_backref_release_cache+0x1fe/0x230 fs/btrfs/backref.c:3163 Code: 0f 0b e8 75 da 90 fd 48 c7 c7 20 c8 5b 8c 48 c7 c6 80 c8 5b 8c 48 c7 c2 80 bf 5b 8c b9 5b 0c 00 00 41 89 e8 e8 23 9e f0 fc 90 <0f> 0b e8 4b da 90 fd 48 c7 c7 c0 c8 5b 8c 48 c7 c6 20 c9 5b 8c 48 RSP: 0018:ffffc9000eb7f7e8 EFLAGS: 00010246 RAX: 0000000000000052 RBX: ffff88801fa82020 RCX: 980914ae5784ef00 RDX: 0000000000000000 RSI: 8000000000000000 RDI: 0000000000000000 RBP: 0000000000000002 R08: ffffc9000eb7f567 R09: 1ffff92001d6feac R10: dffffc0000000000 R11: fffff52001d6fead R12: dffffc0000000000 R13: 1ffff11003f50404 R14: ffff88801fa820f0 R15: ffff8880525fd3b0 FS: 00007facfea6b6c0(0000) GS:ffff88808c2bc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000001000 CR3: 000000001235c000 CR4: 0000000000352ef0 --- 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