From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f70.google.com (mail-oo1-f70.google.com [209.85.161.70]) (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 547FE3B6364 for ; Fri, 17 Apr 2026 10:12:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.70 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776420751; cv=none; b=ZtZjL5CeibGRlSLDu9SsfI/c9H9rZYnRdj3xUyKTyGHw8ffWtQOaEb4JO5Pajj9m4wYpWzYys7/r/aQp+huLuK3f5ILZO5I6+QoaP1wexRyq0JQQ9l4qtiGeJO3dg3M8Dzc1SoPX5AYrNIAnUnSI+lcLAEuZdqYofNHo5IZc8fA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776420751; c=relaxed/simple; bh=tRU5rAiHFe0CF0pBk6LVGyLF+b9vMdIKw/sJNG4MQcM=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To:Cc: Content-Type; b=BBO6pvzEXVWhi/7wt6p+YKSegtjvOU1EQHmv7oJj/li9a7tsqJBd0j3n21XXnnhTvAIcTa2TDVPqbnwrVAfDhsXH+D9SMcZjQ7dDr2jLxRxf1ggOUUUpd3lCzUxhzPMisCY8Zm9tK1GHHFN/wQ0sW/iHdRlewlV/rNqLB6EPQqw= 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=209.85.161.70 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-f70.google.com with SMTP id 006d021491bc7-68ca9de3a6dso455321eaf.1 for ; Fri, 17 Apr 2026 03:12:30 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776420749; x=1777025549; h=cc: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=oefsglqVIph8a1BDnngirTSHMnH5tPQJKiRtOmlWIYM=; b=V3jt4rSLZTKw4spyh31YZGjfoaWdasHu2XlCsD7ePJp8jjqbykXwXt4NNHC4eI6KiV uYP/FMgUB1I9ra+NUq6BUQHlxxTJLbNPHOFKXtLRoOvDJvkD/96W8CcuPEBKCS+ChzT6 nDJsQISAMm9jKcR28dAmi9GFLucNSofCMtFnB619YlOtr93xa2+xUw0EqsC9ZmhJ/JkA TucqL7Ue517KMXIsChluJAVa02/cc9XSlZN/F64de01WH3dsPiWV0R8Zt8swXdwRO5Xc DIgLPt+AjLpHpyx/BzB82JjXhW69SUeNOAkN/VNrht9wTa3JH+LF2cxWF/Kroerz/76k uUUA== X-Forwarded-Encrypted: i=1; AFNElJ8fdiGTUxmhKqMZLNvS/ACqIhMeUpF3BCsBSbCXR1CrHTP6L9At+kbYCMp2uLyrMSDqjkNr5FNI64QF7H0=@vger.kernel.org X-Gm-Message-State: AOJu0YygJufbJu8VaQ15Cq3ei53DUiob8skyOyP9OUtSZlG0kCVdGuzT ZTcBwjJD2VAn+tipFfvth5F9dzXHmjbCgcm90werkHUVto/qOqc+N38s0LiTT2IqTivqFvyZkZz CNEFf01hYQjUW2xyLPwpexVosYTtS4ZBedGmb1FIM1jk2sGr+X7FAnr4nnmo= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:2d0b:b0:67d:e6cf:69a7 with SMTP id 006d021491bc7-69462ee6143mr1017048eaf.38.1776420749404; Fri, 17 Apr 2026 03:12:29 -0700 (PDT) Date: Fri, 17 Apr 2026 03:12:29 -0700 In-Reply-To: <20260417101227.2490949-1-tristmd@gmail.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69e2078d.a00a0220.1cdc.000d.GAE@google.com> Subject: Re: [PATCH] ocfs2: replace BUG_ON with error return in From: syzbot To: tristmd@gmail.com Cc: tristmd@gmail.com, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" > From: Tristan Madani > > #syz test: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master This crash does not have a reproducer. I cannot test it. > > __ocfs2_page_mkwrite > > __ocfs2_page_mkwrite() calls ocfs2_write_end_nolock() and panics the > kernel via BUG_ON if the return value is not equal to the requested > length: > > err = ocfs2_write_end_nolock(mapping, pos, len, len, fsdata); > BUG_ON(err != len); > > When the filesystem encounters I/O errors or on-disk corruption > (e.g. from a crafted image), ocfs2_write_end_nolock() can return > a negative error code or a short write count. This crashes the > kernel instead of returning an error to userspace. > > Replace the BUG_ON with a proper error return path that converts > the failure to a VM_FAULT_SIGBUS, which gracefully reports the > fault to the application. > > Reported-by: syzbot+ea5aff81e35d189b9335@syzkaller.appspotmail.com > Closes: https://syzkaller.appspot.com/bug?extid=ea5aff81e35d189b9335 > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") > Cc: stable@vger.kernel.org > Signed-off-by: Tristan Madani > --- > fs/ocfs2/mmap.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/fs/ocfs2/mmap.c b/fs/ocfs2/mmap.c > index XXXXXXX..XXXXXXX 100644 > --- a/fs/ocfs2/mmap.c > +++ b/fs/ocfs2/mmap.c > @@ -105,7 +105,12 @@ static vm_fault_t __ocfs2_page_mkwrite(struct vm_fault *vmf, > goto out; > } > err = ocfs2_write_end_nolock(mapping, pos, len, len, fsdata); > - BUG_ON(err != len); > + if (unlikely(err != len)) { > + if (err >= 0) > + err = -EIO; > + ret = vmf_error(err); > + goto out; > + } > ret = VM_FAULT_LOCKED; > out: > return ret; > -- > 2.43.0