From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: "Jitindar SIngh, Suraj" <surajjs@amazon.com>
Cc: "cai@lca.pw" <cai@lca.pw>,
"adilger.kernel@dilger.ca" <adilger.kernel@dilger.ca>,
"linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"paulmck@kernel.org" <paulmck@kernel.org>
Subject: Re: null-ptr-deref due to "ext4: fix potential race between online resizing and write operations"
Date: Fri, 21 Feb 2020 19:33:54 -0500 [thread overview]
Message-ID: <20200222003354.GB873427@mit.edu> (raw)
In-Reply-To: <d6ca935e3c70f275ec669fae8984b11f383baa1f.camel@amazon.com>
On Fri, Feb 21, 2020 at 07:58:01PM +0000, Jitindar SIngh, Suraj wrote:
> On Fri, 2020-02-21 at 09:02 -0500, Qian Cai wrote:
> > Reverted the linux-next commit c20bac9bf82c ("ext4: fix potential
> > race between
> > s_flex_groups online resizing and access") fixed the crash below
> > (with line
> > numbers),
>
> Good catch, this is a bug where the dereference of the array
> s_flex_groups needs to happen after the "if (flex_size > 1)" if
> statement in fs/ext4/ialloc.c:373
Cai, thanks for noting the problem! Suraj, I've fixed up the patch on
the ext4.git tree.
- Ted
prev parent reply other threads:[~2020-02-22 0:34 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-21 14:02 null-ptr-deref due to "ext4: fix potential race between online resizing and write operations" Qian Cai
2020-02-21 19:58 ` Jitindar SIngh, Suraj
2020-02-22 0:33 ` Theodore Y. Ts'o [this message]
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