From: Andrew Morton <akpm@linux-foundation.org>
To: Eugeniu Rosca <erosca@de.adit-jv.com>
Cc: Dongli Zhang <dongli.zhang@oracle.com>, <linux-mm@kvack.org>,
<stable@vger.kernel.org>, Eugeniu Rosca <roscaeugeniu@gmail.com>
Subject: Re: [PATCH] mm: slub: fix conversion of freelist_corrupted()
Date: Tue, 11 Aug 2020 13:49:09 -0700 [thread overview]
Message-ID: <20200811134909.536004dcfc4c78204313dcd2@linux-foundation.org> (raw)
In-Reply-To: <20200811124656.10308-1-erosca@de.adit-jv.com>
On Tue, 11 Aug 2020 14:46:56 +0200 Eugeniu Rosca <erosca@de.adit-jv.com> wrote:
> Commit 52f23478081ae0 ("mm/slub.c: fix corrupted freechain in
> deactivate_slab()") suffered an update when picked up from LKML [1].
>
> Specifically, relocating 'freelist = NULL' into 'freelist_corrupted()'
> created a no-op statement. Fix it by sticking to the behavior intended
> in the original patch [1]. Prefer the lowest-line-count solution.
>
> [1] https://lore.kernel.org/linux-mm/20200331031450.12182-1-dongli.zhang@oracle.com/
>
> ...
>
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -677,7 +677,6 @@ static bool freelist_corrupted(struct kmem_cache *s, struct page *page,
> if ((s->flags & SLAB_CONSISTENCY_CHECKS) &&
> !check_valid_pointer(s, page, nextfree)) {
> object_err(s, page, freelist, "Freechain corrupt");
> - freelist = NULL;
> slab_fix(s, "Isolate corrupted freechain");
> return true;
> }
> @@ -2184,8 +2183,10 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page,
> * 'freelist' is already corrupted. So isolate all objects
> * starting at 'freelist'.
> */
> - if (freelist_corrupted(s, page, freelist, nextfree))
> + if (freelist_corrupted(s, page, freelist, nextfree)) {
> + freelist = NULL;
> break;
> + }
>
> do {
> prior = page->freelist;
Looks right.
What are the runtime effects of this change? In other words, what are
the end user visible effects of the present defect?
next prev parent reply other threads:[~2020-08-11 20:49 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-11 12:46 [PATCH] mm: slub: fix conversion of freelist_corrupted() Eugeniu Rosca
2020-08-11 20:49 ` Andrew Morton [this message]
2020-08-12 9:06 ` Eugeniu Rosca
2020-08-14 6:57 ` Dongli Zhang
2020-08-14 7:46 ` Eugeniu Rosca
2020-08-14 19:43 ` Dongli Zhang
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