From: Matthew Wilcox <willy@infradead.org>
To: "zhaoyang.huang" <zhaoyang.huang@unisoc.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Zhaoyang Huang <huangzhaoyang@gmail.com>,
steve.kang@unisoc.com
Subject: Re: [PATCH] mm: fix a race scenario in folio_isolate_lru
Date: Fri, 15 Mar 2024 12:46:29 +0000 [thread overview]
Message-ID: <ZfRDJTrFJq3KSbIB@casper.infradead.org> (raw)
In-Reply-To: <20240314083921.1146937-1-zhaoyang.huang@unisoc.com>
On Thu, Mar 14, 2024 at 04:39:21PM +0800, zhaoyang.huang wrote:
> From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
>
> Panic[1] reported which is caused by lruvec->list break. Fix the race
> between folio_isolate_lru and release_pages.
>
> race condition:
> release_pages could meet a non-refered folio which escaped from being
> deleted from LRU but add to another list_head
I don't think the bug is in folio_isolate_lru() but rather in its
caller.
* Context:
*
* (1) Must be called with an elevated refcount on the folio. This is a
* fundamental difference from isolate_lru_folios() (which is called
* without a stable reference).
So when release_pages() runs, it must not see a refcount decremented to
zero, because the caller of folio_isolate_lru() is supposed to hold one.
Your stack trace is for the thread which is calling release_pages(), not
the one calling folio_isolate_lru(), so I can't help you debug further.
next prev parent reply other threads:[~2024-03-15 12:46 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-14 8:39 [PATCH] mm: fix a race scenario in folio_isolate_lru zhaoyang.huang
2024-03-15 11:03 ` Zhaoyang Huang
2024-03-15 12:46 ` Matthew Wilcox [this message]
2024-03-16 8:53 ` Zhaoyang Huang
2024-03-16 14:59 ` Matthew Wilcox
2024-03-17 4:07 ` Zhaoyang Huang
2024-03-17 20:46 ` Matthew Wilcox
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