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From: Matthew Wilcox <willy@infradead.org>
To: 李龙兴 <coregee2000@gmail.com>
Cc: syzkaller@googlegroups.com, akpm@linux-foundation.org,
	linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org
Subject: Re: [Kernel Bug] KASAN: slab-use-after-free Read in filemap_free_folio
Date: Mon, 2 Feb 2026 14:14:06 +0000	[thread overview]
Message-ID: <aYCxLsCVUT_kky4o@casper.infradead.org> (raw)
In-Reply-To: <CAHPqNmyHRaGj0fn+2FvvaJYi4WYOVmai6XX3bRCwbAZoj_GwWg@mail.gmail.com>

On Mon, Feb 02, 2026 at 02:20:50PM +0800, 李龙兴 wrote:
> Dear Linux kernel developers and maintainers,
> 
> We would like to report a new kernel bug found by our tool. KASAN:

Don't be syzbot.  Get your changes into syzkaller upstream and let
syzbot do its thing.

> Allocated by task 49607:
>  kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
>  kasan_save_track+0x14/0x30 mm/kasan/common.c:77
>  unpoison_slab_object mm/kasan/common.c:342 [inline]
>  __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:368
>  kasan_slab_alloc include/linux/kasan.h:252 [inline]
>  slab_post_alloc_hook mm/slub.c:4978 [inline]
>  slab_alloc_node mm/slub.c:5288 [inline]
>  kmem_cache_alloc_lru_noprof+0x254/0x6e0 mm/slub.c:5307
>  ext4_alloc_inode+0x28/0x610 fs/ext4/super.c:1393

I'd suggest this is an ext4 problem, not a pagecache problem.

syzbot has good heuristics for this kind of thing now.  You don't.


      reply	other threads:[~2026-02-02 14:14 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-02  6:20 李龙兴
2026-02-02 14:14 ` Matthew Wilcox [this message]

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