linux-kernel - Re: [PATCH 09/12] badblocks: fix missing bad blocks on retry in _badblocks

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: <55469db7-f93d-d174-ec8c-47e7e9b3b001@huaweicloud.com>
Date: Sat, 22 Feb 2025 09:28:10 +0800
From: Yu Kuai <yukuai1@...weicloud.com>
To: Zheng Qixing <zhengqixing@...weicloud.com>, axboe@...nel.dk,
 song@...nel.org, colyli@...nel.org, dan.j.williams@...el.com,
 vishal.l.verma@...el.com, dave.jiang@...el.com, ira.weiny@...el.com,
 dlemoal@...nel.org, yanjun.zhu@...ux.dev, kch@...dia.com, hare@...e.de,
 zhengqixing@...wei.com, john.g.garry@...cle.com, geliang@...nel.org,
 xni@...hat.com, colyli@...e.de
Cc: linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-raid@...r.kernel.org, nvdimm@...ts.linux.dev, yi.zhang@...wei.com,
 yangerkun@...wei.com, "yukuai (C)" <yukuai3@...wei.com>
Subject: Re: [PATCH 09/12] badblocks: fix missing bad blocks on retry in
 _badblocks_check()

在 2025/02/21 16:11, Zheng Qixing 写道:
> From: Zheng Qixing <zhengqixing@...wei.com>
> 
> The bad blocks check would miss bad blocks when retrying under contention,
> as checking parameters are not reset. These stale values from the previous
> attempt could lead to incorrect scanning in the subsequent retry.
> 
> Move seqlock to outer function and reinitialize checking state for each
> retry. This ensures a clean state for each check attempt, preventing any
> missed bad blocks.
> 
> Fixes: 3ea3354cb9f0 ("badblocks: improve badblocks_check() for multiple ranges handling")
> Signed-off-by: Zheng Qixing <zhengqixing@...wei.com>
> ---
>   block/badblocks.c | 50 +++++++++++++++++++++++------------------------
>   1 file changed, 24 insertions(+), 26 deletions(-)
> 
LGTM
Reviewed-by: Yu Kuai <yukuai3@...wei.com>

> diff --git a/block/badblocks.c b/block/badblocks.c
> index 381f9db423d6..79d91be468c4 100644
> --- a/block/badblocks.c
> +++ b/block/badblocks.c
> @@ -1191,31 +1191,12 @@ static int _badblocks_clear(struct badblocks *bb, sector_t s, int sectors)
>   static int _badblocks_check(struct badblocks *bb, sector_t s, int sectors,
>   			    sector_t *first_bad, int *bad_sectors)
>   {
> -	int unacked_badblocks, acked_badblocks;
>   	int prev = -1, hint = -1, set = 0;
>   	struct badblocks_context bad;
> -	unsigned int seq;
> +	int unacked_badblocks = 0;
> +	int acked_badblocks = 0;
> +	u64 *p = bb->page;
>   	int len, rv;
> -	u64 *p;
> -
> -	WARN_ON(bb->shift < 0 || sectors == 0);
> -
> -	if (bb->shift > 0) {
> -		sector_t target;
> -
> -		/* round the start down, and the end up */
> -		target = s + sectors;
> -		rounddown(s, 1 << bb->shift);
> -		roundup(target, 1 << bb->shift);
> -		sectors = target - s;
> -	}
> -
> -retry:
> -	seq = read_seqbegin(&bb->lock);
> -
> -	p = bb->page;
> -	unacked_badblocks = 0;
> -	acked_badblocks = 0;
>   
>   re_check:
>   	bad.start = s;
> @@ -1281,9 +1262,6 @@ static int _badblocks_check(struct badblocks *bb, sector_t s, int sectors,
>   	else
>   		rv = 0;
>   
> -	if (read_seqretry(&bb->lock, seq))
> -		goto retry;
> -
>   	return rv;
>   }
>   
> @@ -1324,7 +1302,27 @@ static int _badblocks_check(struct badblocks *bb, sector_t s, int sectors,
>   int badblocks_check(struct badblocks *bb, sector_t s, int sectors,
>   			sector_t *first_bad, int *bad_sectors)
>   {
> -	return _badblocks_check(bb, s, sectors, first_bad, bad_sectors);
> +	unsigned int seq;
> +	int rv;
> +
> +	WARN_ON(bb->shift < 0 || sectors == 0);
> +
> +	if (bb->shift > 0) {
> +		/* round the start down, and the end up */
> +		sector_t target = s + sectors;
> +
> +		rounddown(s, 1 << bb->shift);
> +		roundup(target, 1 << bb->shift);
> +		sectors = target - s;
> +	}
> +
> +retry:
> +	seq = read_seqbegin(&bb->lock);
> +	rv = _badblocks_check(bb, s, sectors, first_bad, bad_sectors);
> +	if (read_seqretry(&bb->lock, seq))
> +		goto retry;
> +
> +	return rv;
>   }
>   EXPORT_SYMBOL_GPL(badblocks_check);
>   
>