From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f71.google.com (mail-oo1-f71.google.com [209.85.161.71]) (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 D4DD8285C80 for ; Mon, 9 Mar 2026 18:09:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.71 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773079770; cv=none; b=QVmzSIp6c5PBygEDfY8eR3/m8eOfwa+LIZio2C56hJPMVJ+4YxfmPlWAEhX0Ezr7O09POWUWiOx3iaeBaafXwf65d6evXttCL37CQsMOeBFGgK7RJ/rW90Q/gvvJSCHZtUEn5OholYXrnGgkDvt9rgYx/MdPHtIksESe6ImGTec= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773079770; c=relaxed/simple; bh=SznvAvqNCRElUNPMzSkqSUSr8mKELL3XsKc1SwggWmw=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=NksgcnNxMGn+LQMXirCobt1UHm9/rzSvZlJSzhf8If2mL4c82V/BneMIiEgcHSMCdVoCY54v+UjF50W44rRCJKcRO7nenUIqpDYglIFDeOLgM7RJ1p83tpcj4wQ8oWB3149jjwLA9EBlKx6dd/y9owVDukJ7878gh8N9jlGfrKw= 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=209.85.161.71 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-oo1-f71.google.com with SMTP id 006d021491bc7-67bb77eb9f8so9409573eaf.1 for ; Mon, 09 Mar 2026 11:09:28 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1773079768; x=1773684568; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=fMD6/Q/SdweF5qLhXKzO6kQHbt/0bKCUTR88DfHKC0k=; b=VCcPYvZVTFye+vav68OQNaaytjFlm6dEAeBfb6w6QGZFMqvV8f1RUBzd/gAjKI9CaN R4RJfggEH1DA4TSkRYZEQ57+8lRnjc8Qv3+9uENH+icbhAzSyhQvbioRjYjdiFLlGNQC 65y6cC1EfZGyb6mPGGfdewRaV/onG9QQPUMPx0bE0C+TfV4ZBG4Vi5s2gySPOWVn/1Wq zELma0dm9LzUtfm+QdTMG5JNNblYRTBZV772rBOoboOQZ/1DEQW3eD+wAF9qXZAIDr/y VNLQp7WbN5Z+wg2DcnPfU4bdWVO0lQQOmW6S/Q5fG0bTlpSXGDK9kUugzl6zUKhQcuRa j2UA== X-Forwarded-Encrypted: i=1; AJvYcCU2JTMR5RP1/OCHM0/DzbLZFcJXYtGsAo5JmMfAUf5iJHoJ6Vsk2CDwMMFKm1+B4BP+5HO7OyW36One5g==@vger.kernel.org X-Gm-Message-State: AOJu0YyoXYKMJTqjxdfhOD5ErgJMJ9XrKDegruvN9+CeVss0UbIwYEaY O7QKoLXz8E+ZBFLJaudsUIoHTw9XCGhDEq4nd5ryHFRfx08jCrQQgTffdWWhBhxRZYrGc00DEOV tUbkPhRTTBp0c5TU/nu4Khcbb8xm1MYC8hACeJIQdxS7I4QddNZHyHuEqA6E= Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:4d09:b0:67b:aa33:408f with SMTP id 006d021491bc7-67baa33467amr4720903eaf.55.1773079767903; Mon, 09 Mar 2026 11:09:27 -0700 (PDT) Date: Mon, 09 Mar 2026 11:09:27 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69af0cd7.050a0220.310d8.0030.GAE@google.com> Subject: [syzbot] [btrfs?] kernel BUG in btrfs_backref_release_cache (3) From: syzbot To: clm@fb.com, dsterba@suse.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: c107785c7e8d Merge tag 'modules-7.0-rc3.fixes' of git://gi.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=12d0ab5a580000 kernel config: https://syzkaller.appspot.com/x/.config?x=c5c49ee0942d1cdb dashboard link: https://syzkaller.appspot.com/bug?extid=128c98b49b7ffb4c8fa3 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 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-c107785c.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/f3bc281ac705/vmlinux-c107785c.xz kernel image: https://storage.googleapis.com/syzbot-assets/ecd5165e5812/bzImage-c107785c.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+128c98b49b7ffb4c8fa3@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): found 1 extents, stage: move data extents BTRFS info (device loop0): relocating block group 5242880 flags data|metadata BTRFS info (device loop0): found 10 extents, stage: move data extents assertion failed: !cache->nr_nodes :: 0, in fs/btrfs/backref.c:3151 ------------[ cut here ]------------ kernel BUG at fs/btrfs/backref.c:3151! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI CPU: 0 UID: 0 PID: 5318 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+0x234/0x260 fs/btrfs/backref.c:3151 Code: 0f 0b e8 6f 74 bd fd 48 c7 c7 e0 96 17 8c 48 c7 c6 00 9e 17 8c 31 d2 48 c7 c1 80 97 17 8c 41 b8 4f 0c 00 00 e8 9d 85 1f fd 90 <0f> 0b e8 45 74 bd fd 48 c7 c7 e0 96 17 8c 48 c7 c6 40 9e 17 8c 31 RSP: 0018:ffffc9000dd477a8 EFLAGS: 00010246 RAX: 0000000000000043 RBX: ffff8880434c6020 RCX: e86cf94f153c5b00 RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000 RBP: 0000000000000002 R08: ffffc9000dd47527 R09: 1ffff92001ba8ea4 R10: dffffc0000000000 R11: fffff52001ba8ea5 R12: dffffc0000000000 R13: 1ffff11008698c04 R14: ffff8880434c60f0 R15: 1ffff11008698c21 FS: 00007f83542826c0(0000) GS:ffff88808ca56000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055819b279168 CR3: 0000000044955000 CR4: 0000000000352ef0 Call Trace: relocate_block_group+0xb80/0xe90 fs/btrfs/relocation.c:3628 do_nonremap_reloc+0xa8/0x5b0 fs/btrfs/relocation.c:5251 btrfs_relocate_block_group+0x75b/0xae0 fs/btrfs/relocation.c:5410 btrfs_relocate_chunk+0x10f/0x810 fs/btrfs/volumes.c:3590 __btrfs_balance+0x1dab/0x2ae0 fs/btrfs/volumes.c:4492 btrfs_balance+0xafa/0x11f0 fs/btrfs/volumes.c:4879 btrfs_ioctl_balance+0x3d3/0x610 fs/btrfs/ioctl.c:3445 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:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f835339c799 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:00007f8354281fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f8353616090 RCX: 00007f835339c799 RDX: 0000200000000180 RSI: 00000000c4009420 RDI: 0000000000000006 RBP: 00007f8353432bd9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8353616128 R14: 00007f8353616090 R15: 00007ffd7d2ef558 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:btrfs_backref_release_cache+0x234/0x260 fs/btrfs/backref.c:3151 Code: 0f 0b e8 6f 74 bd fd 48 c7 c7 e0 96 17 8c 48 c7 c6 00 9e 17 8c 31 d2 48 c7 c1 80 97 17 8c 41 b8 4f 0c 00 00 e8 9d 85 1f fd 90 <0f> 0b e8 45 74 bd fd 48 c7 c7 e0 96 17 8c 48 c7 c6 40 9e 17 8c 31 RSP: 0018:ffffc9000dd477a8 EFLAGS: 00010246 RAX: 0000000000000043 RBX: ffff8880434c6020 RCX: e86cf94f153c5b00 RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000 RBP: 0000000000000002 R08: ffffc9000dd47527 R09: 1ffff92001ba8ea4 R10: dffffc0000000000 R11: fffff52001ba8ea5 R12: dffffc0000000000 R13: 1ffff11008698c04 R14: ffff8880434c60f0 R15: 1ffff11008698c21 FS: 00007f83542826c0(0000) GS:ffff88808ca56000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055819b279168 CR3: 0000000044955000 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