From: David Sterba <dsterba@suse.cz>
To: fdmanana@kernel.org
Cc: linux-btrfs@vger.kernel.org
Subject: Re: [PATCH] btrfs: zoned: fix use-after-free due to race with dev replace
Date: Thu, 9 May 2024 19:13:36 +0200 [thread overview]
Message-ID: <20240509171336.GL13977@twin.jikos.cz> (raw)
In-Reply-To: <ccab86c78fc2a1fd6dd320efa289863df7158ca9.1715167144.git.fdmanana@suse.com>
On Wed, May 08, 2024 at 12:20:40PM +0100, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
>
> While loading a zone's info during creation of a block group, we can race
> with a device replace operation and then trigger a use-after-free on the
> device that was just replaced (source device of the replace operation).
>
> This happens because at btrfs_load_zone_info() we extract a device from
> the chunk map into a local variable and then use the device while not
> under the protection of the device replace rwsem. So if there's a device
> replace operation happening when we extract the device and that device
> is the source of the replace operation, we will trigger a use-after-free
> if before we finish using the device the replace operaton finishes and
> frees the device.
>
> Fix this by enlarging the critical section under the protection of the
> device replace rwsem so that all uses of the device are done inside the
> critical section.
>
> Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
I'll add CC for 6.1+ before sending a pull request, there are some
dependencies but otherwise it applies cleanly.
prev parent reply other threads:[~2024-05-09 17:13 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-08 11:20 [PATCH] btrfs: zoned: fix use-after-free due to race with dev replace fdmanana
2024-05-08 15:29 ` Johannes Thumshirn
2024-05-09 17:13 ` David Sterba [this message]
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