From: Andrew Morton <akpm@linux-foundation.org>
To: Jianlin Shi <shijianlin11@foxmail.com>
Cc: linux-mm@kvack.org, vbabka@kernel.org, hannes@cmpxchg.org,
surenb@google.com, mhocko@suse.com, jackmanb@google.com,
ziy@nvidia.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] mm/page_alloc: only update lowmem_reserve_ratio on sysctl write
Date: Sat, 1 Aug 2026 11:44:34 -0700 [thread overview]
Message-ID: <20260801114434.232c97a74d9616c43aac2456@linux-foundation.org> (raw)
In-Reply-To: <tencent_1BB7A5C4D5EEA67346634417753190E92A09@qq.com>
On Sat, 1 Aug 2026 23:11:25 +0800 Jianlin Shi <shijianlin11@foxmail.com> wrote:
> lowmem_reserve_ratio_sysctl_handler() ignores the return value of
> proc_dointvec_minmax() and always calls setup_per_zone_lowmem_reserve(),
> even for read operations.
>
> Fix two issues:
>
> 1. Propagate errors from proc_dointvec_minmax() instead of always
> returning success. For example, writing non-integer garbage to the
> sysctl now returns an error instead of silently succeeding with
> unchanged values.
AI review suggest that this caused a new problem:
https://sashiko.dev/#/patchset/tencent_1BB7A5C4D5EEA67346634417753190E92A09@qq.com
Not sure what to do here. Perhaps pass proc_dointvec_minmax() a
temporary then copy that into sysctl_lowmem_reserve_ratio if all
proc_dointvec_minmax() returns "OK".
But really this is a flaw in proc_dointvec_minmax() isn't it? It
shouldn't update the table data until all the data has been validated.
next prev parent reply other threads:[~2026-08-01 18:44 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-28 10:32 [PATCH] mm/page_alloc: only update lowmem_reserve_ratio on sysctl write Jianlin Shi
2026-07-30 15:28 ` Vlastimil Babka (SUSE)
2026-07-31 3:36 ` Jianlin Shi
2026-07-31 3:42 ` [PATCH v2] " Jianlin Shi
2026-07-31 8:06 ` Vlastimil Babka (SUSE)
2026-08-01 7:36 ` Johannes Weiner
2026-08-01 15:11 ` [PATCH v3] " Jianlin Shi
2026-08-01 18:44 ` Andrew Morton [this message]
2026-08-02 14:31 ` Jianlin Shi
2026-08-03 8:27 ` Vlastimil Babka (SUSE)
2026-08-04 12:20 ` Joel Granados
2026-08-04 14:33 ` Vlastimil Babka (SUSE)
2026-08-06 8:27 ` Joel Granados
2026-08-02 14:57 ` [PATCH v4] " Jianlin Shi
2026-08-04 0:48 ` Andrew Morton
2026-08-06 7:32 ` Jianlin Shi
2026-08-06 8:27 ` [PATCH v5] " Jianlin Shi
2026-08-06 13:50 ` Johannes Weiner
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