linux-kernel - Re: [RFC PATCH v4 5/5] btrfs: ioctl: don't free iov when -EAGAIN in uring encoded read

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <849ce82d-d87a-428a-be79-abdeb53a1a99@gmail.com>
Date: Tue, 18 Mar 2025 07:21:00 +0000
From: Pavel Begunkov <asml.silence@...il.com>
To: Sidong Yang <sidong.yang@...iosa.ai>, Josef Bacik <josef@...icpanda.com>,
 David Sterba <dsterba@...e.com>, Jens Axboe <axboe@...nel.dk>
Cc: linux-btrfs@...r.kernel.org, linux-kernel@...r.kernel.org,
 io-uring@...r.kernel.org, Mark Harmstone <maharmstone@...a.com>
Subject: Re: [RFC PATCH v4 5/5] btrfs: ioctl: don't free iov when -EAGAIN in
 uring encoded read

On 3/17/25 13:57, Sidong Yang wrote:
> This patch fixes a bug on encoded_read. In btrfs_uring_encoded_read(),
> btrfs_encoded_read could return -EAGAIN when receiving requests concurrently.
> And data->iov goes to out_free and it freed and return -EAGAIN. io-uring
> subsystem would call it again and it doesn't reset data. And data->iov
> freed and iov_iter reference it. iov_iter would be used in
> btrfs_uring_read_finished() and could be raise memory bug.

Fixes should go first. Please send it separately, and CC Mark.
A "Fixes" tag would also be good to have.

> Signed-off-by: Sidong Yang <sidong.yang@...iosa.ai>
> ---
>   fs/btrfs/ioctl.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index a7b52fd99059..02fa8dd1a3ce 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -4922,6 +4922,9 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue
>   
>   	ret = btrfs_encoded_read(&kiocb, &data->iter, &data->args, &cached_state,
>   				 &disk_bytenr, &disk_io_size);
> +
> +	if (ret == -EAGAIN)
> +		goto out_acct;
>   	if (ret < 0 && ret != -EIOCBQUEUED)
>   		goto out_free;
>   

-- 
Pavel Begunkov