From nobody Sat Feb 7 22:21:33 2026 Received: from mail-oi1-f198.google.com (mail-oi1-f198.google.com [209.85.167.198]) (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 0A2292E7648 for ; Fri, 9 Jan 2026 09:09:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.198 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767949792; cv=none; b=t+4rV3gByEOgaqQIVBj24ip4LyXclIqty2tjIdmtYlAmsaYJ79/9aumEbUBApJ3UaW232ZqEraTY3rydClg1f8MFLNx19WJQ1Kb/f1/UEl6B2q4EkzY/QO5YDPQB7moDUmMOWJp3w1zYPVdNJVixkpfqVneuNrqC3q4cp2hrY80= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767949792; c=relaxed/simple; bh=S6IcWEbTeMQSJRQyYpjUj60+zDDylLZVN54kWEAfHQ4=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=irV/Um2UOtWA5k0uZhBZdgpnBr3K/mbj68HwzvY6w42/xlatLv1WAtqnM2xITuIhwkSon3c4pcQrrm7HQn/kAZjRpZXKdzFfot1UQoy55BqL9+WCH891V5bAArUJs5aQ8g/OScXGg5QJ1bQhj/yntOacbU8ClhJiJbpBSGMYF/Q= 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=209.85.167.198 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-oi1-f198.google.com with SMTP id 5614622812f47-459f458b781so7435403b6e.3 for ; Fri, 09 Jan 2026 01:09:50 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767949790; x=1768554590; h=to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=it33QHCudcAfHpbb6qw6WIWL1M52rMXv5UnK7VRw8iY=; b=NQygyG7a4h8orLScOfkoqz6BhKKCTU03e+KY8EsyvHNX2HAZ9gTSeZYcRjJHF6A+Ei T7KFMNX3wU6C0WIJhzyfBYVzgMT6lYd1imG3KCqswxmyRIs6D1jjCeOKbc8Rm8Zz3E6P IlR605BmzAhN6C/hbHdxbWQGrKkSZK4nNmTV2xA4qazm7TjnSgOhYArkPg6A1rx3F4Y6 i//QxnrKyQegetrCogkxTl/DnpDQ+BLjAJG61SZkHgrbdmsLyeElATxatHI8zp2JlWO0 WO5TriQL1gv+ioZaFPXUaD/veIclWIYH//J1gFO08ZVDVcmWahKDs2L0zTgy7/aTd0Xk 46lA== X-Gm-Message-State: AOJu0Yypq10iUNKiiTQFbwho/L1FRpXlaP5wSI7qxkaL/Eq77+Lvr8S9 CbBBAPKxF/MgEH+2wCq0Osaa7awWeKRHr31ZuwSLGYf/BbM7mTP5Kq6xHmatBxdbIsNPFm5Bb7F w0mGXDKD+JIk1PKrx6lKIuNEdcbFz3bc+0VfM13DmTXlWuN5ClFOiJGCw6Ug= X-Google-Smtp-Source: AGHT+IFvFpRWJHujhbffXARCzsUoZbDXhk1gMM6zP3Vl/fgcgqlGWYxaNY5LQzOVAFvWORIrjglCqvj8NW8G+HsaEIr1lS5Rpl5U Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:16a1:b0:450:275c:87d8 with SMTP id 5614622812f47-45a6bdfc74emr4101510b6e.32.1767949790058; Fri, 09 Jan 2026 01:09:50 -0800 (PST) Date: Fri, 09 Jan 2026 01:09:50 -0800 In-Reply-To: <695faa63.050a0220.1c677c.039b.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6960c5de.050a0220.1c677c.03c0.GAE@google.com> Subject: Forwarded: [PATCH] btrfs: debug block device parameters before reading superblock From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" For archival purposes, forwarding an incoming command email to linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com. *** Subject: [PATCH] btrfs: debug block device parameters before reading superb= lock Author: kartikey406@gmail.com #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git= master Debug patch to understand NULL pointer dereference in create_empty_buffers. Print logical_block_size and mapping_min_folio_order to identify the correct check needed. NOT FOR MERGE - debug only. Signed-off-by: Deepanshu Kartikey --- fs/btrfs/volumes.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 13c514684cfb..40de5be63172 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1341,6 +1341,9 @@ struct btrfs_super_block *btrfs_read_disk_super(struc= t block_device *bdev, struct address_space *mapping =3D bdev->bd_mapping; int ret; =20 + pr_err("DEBUG btrfs: logical_block_size=3D%u min_folio_order=3D%u\n", + bdev_logical_block_size(bdev), + mapping_min_folio_order(mapping)); bytenr_orig =3D btrfs_sb_offset(copy_num); ret =3D btrfs_sb_log_location_bdev(bdev, copy_num, READ, &bytenr); if (ret < 0) { --=20 2.43.0