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From: Andrew Morton <akpm@linux-foundation.org>
To: Sang-Heon Jeon <ekffu200098@gmail.com>
Cc: Thomas Gleixner <tglx@kernel.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] debugobjects: Fix NULL pointer dereference in kmem_alloc_batch()
Date: Sun, 8 Nov 2026 20:56:00 -0800	[thread overview]
Message-ID: <20261108205600.3e737ad18ce85b6ce3049309@linux-foundation.org> (raw)
In-Reply-To: <20261109041215.11280-2-ekffu200098@gmail.com>

On Mon,  9 Nov 2026 13:12:10 +0900 Sang-Heon Jeon <ekffu200098@gmail.com> wrote:

> During boot, debug_objects_replace_static_objects() calls
> kmem_alloc_batch() while obj_cache is still NULL.
> 
> If kmem_cache_zalloc() fails, kmem_alloc_batch() tries to free the
> allocated objects with free_object_list(). But free_object_list()
> always calls kmem_cache_free() with obj_cache, which causes a NULL
> pointer dereference.
> 
> So use the cache passed to kmem_alloc_batch() instead.

Thanks.

We conventionally assume that memory allocations in __init code cannot
fail.  Because if they do fail, something has already gone horribly
wrong with the kernel and it simply isn't viable.  If an unchecked
allocation results in an oops then that's fine - it was inevitable
anyway.



  reply	other threads:[~2026-11-09  4:56 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-11-09  4:12 [PATCH 0/2] " Sang-Heon Jeon
2026-11-09  4:12 ` [PATCH 1/2] " Sang-Heon Jeon
2026-11-09  4:56   ` Andrew Morton [this message]
2026-11-09  5:15     ` Sang-Heon Jeon
2026-11-09  4:12 ` [PATCH 2/2] debugobjects: Use free_object_list() in the boot error path Sang-Heon Jeon

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