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From: David Sterba <dsterba@suse.cz>
To: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: David Sterba <dsterba@suse.com>,
	linux-btrfs@vger.kernel.org, Anand Jain <anand.jain@oracle.com>,
	Nikolay Borisov <nborisov@suse.com>,
	syzbot+582e66e5edf36a22c7b0@syzkaller.appspotmail.com
Subject: Re: [PATCH v2] btrfs: don't access possibly stale fs_info data for printing duplicate device
Date: Mon, 16 Nov 2020 16:38:33 +0100	[thread overview]
Message-ID: <20201116153833.GO6756@twin.jikos.cz> (raw)
In-Reply-To: <0e9eb675e0a199bf034f13c58fbe5678f4e94a3c.1605513154.git.johannes.thumshirn@wdc.com>

On Mon, Nov 16, 2020 at 04:52:54PM +0900, Johannes Thumshirn wrote:
> Syzbot reported a possible use-after-free when printing a duplicate device
> warning device_list_add().
> 
> At this point it can happen that a btrfs_device::fs_info is not correctly
> setup yet, so we're accessing stale data, when printing the warning
> message using the btrfs_printk() wrappers.
> 
> Instead of printing possibly uninitialized or already freed memory in
> btrfs_printk(), explicitly pass in a NULL fs_info so the printing of the
> device name will be skipped altogether.

This would be good to add some info about the evolution of the fix, also
a comment saying why we can't use fs_info.

  parent reply	other threads:[~2020-11-16 15:40 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-16  7:52 [PATCH v2] btrfs: don't access possibly stale fs_info data for printing duplicate device Johannes Thumshirn
2020-11-16  7:59 ` Nikolay Borisov
2020-11-16 15:38 ` David Sterba [this message]
2020-11-17  7:20 ` Anand Jain
2020-11-17  8:19   ` Johannes Thumshirn
2020-11-17 10:50     ` Anand Jain

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