linux-kernel - Re: [dm-devel] [PATCH -next v2 6/6] md: enhance checking in md_check

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: <d5407a0d-f97b-ce31-9319-911695f2e5e8@redhat.com>
Date:   Wed, 14 Jun 2023 15:24:26 +0800
From:   Xiao Ni <xni@...hat.com>
To:     Yu Kuai <yukuai1@...weicloud.com>, guoqing.jiang@...ux.dev,
        agk@...hat.com, snitzer@...nel.org, dm-devel@...hat.com,
        song@...nel.org
Cc:     yi.zhang@...wei.com, yangerkun@...wei.com,
        linux-kernel@...r.kernel.org, linux-raid@...r.kernel.org,
        yukuai3@...wei.com
Subject: Re: [dm-devel] [PATCH -next v2 6/6] md: enhance checking in
 md_check_recovery()


在 2023/5/29 下午9:20, Yu Kuai 写道:
> From: Yu Kuai <yukuai3@...wei.com>
>
> For md_check_recovery():
>
> 1) if 'MD_RECOVERY_RUNING' is not set, register new sync_thread.
> 2) if 'MD_RECOVERY_RUNING' is set:
>   a) if 'MD_RECOVERY_DONE' is not set, don't do anything, wait for
>     md_do_sync() to be done.
>   b) if 'MD_RECOVERY_DONE' is set, unregister sync_thread. Current code
>     expects that sync_thread is not NULL, otherwise new sync_thread will
>     be registered, which will corrupt the array.
>
> Make sure md_check_recovery() won't register new sync_thread if
> 'MD_RECOVERY_RUNING' is still set, and a new WARN_ON_ONCE() is added for
> the above corruption,
>
> Signed-off-by: Yu Kuai <yukuai3@...wei.com>
> ---
>   drivers/md/md.c | 22 +++++++++++++++-------
>   1 file changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index f90226e6ddf8..9da0fc906bbd 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -9397,16 +9397,24 @@ void md_check_recovery(struct mddev *mddev)
>   		if (mddev->sb_flags)
>   			md_update_sb(mddev, 0);
>   
> -		if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
> -		    !test_bit(MD_RECOVERY_DONE, &mddev->recovery)) {
> -			/* resync/recovery still happening */
> -			clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
> -			goto unlock;
> -		}
> -		if (mddev->sync_thread) {
> +		/*
> +		 * Never start a new sync thread if MD_RECOVERY_RUNNING is
> +		 * still set.
> +		 */
> +		if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) {
> +			if (!test_bit(MD_RECOVERY_DONE, &mddev->recovery)) {
> +				/* resync/recovery still happening */
> +				clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
> +				goto unlock;
> +			}
> +
> +			if (WARN_ON_ONCE(!mddev->sync_thread))
> +				goto unlock;
> +
>   			md_reap_sync_thread(mddev);
>   			goto unlock;
>   		}
> +
>   		/* Set RUNNING before clearing NEEDED to avoid
>   		 * any transients in the value of "sync_action".
>   		 */

It makes the logical more clear.

Reviewed-by: Xiao Ni <xni@...hat.com>