From: Dave Hansen <dave.hansen@intel.com>
To: Thorsten Blum <thorsten.blum@linux.dev>,
kernel test robot <oliver.sang@intel.com>
Cc: oe-lkp@lists.linux.dev, lkp@intel.com, linux-sgx@vger.kernel.org,
Jarkko Sakkinen <jarkko@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/sgx: Replace kmalloc() + copy_from_user() with memdup_user()
Date: Thu, 25 Sep 2025 08:37:22 -0700 [thread overview]
Message-ID: <ee907cef-684b-49a3-84c3-ba2efead9caa@intel.com> (raw)
In-Reply-To: <9A7F15AA-836C-457B-BFD9-B37497B16A27@linux.dev>
On 9/22/25 06:18, Thorsten Blum wrote:
>> The kernel config and materials to reproduce are available at:
>> https://download.01.org/0day-ci/archive/20250921/202509211747.1edb60f-
>> lkp@intel.com
> Can someone explain why this test is failing?
>
> After some digging into SGX, I think it's the different allocators
> kmalloc() vs. kmem_buckets_alloc_track_caller(), but I'm not exactly
> sure why it fails.
>
> Perhaps we should add a comment for anyone else trying to replace this?
I can't fathom that this is an SGX problem. The SGX code is as dirt
simple as it gets:
secs = kmalloc(PAGE_SIZE, GFP_KERNEL);
There are literally thousands of those in the kernel.
memdup_user() look suspicious to me, though:
p = kmem_buckets_alloc_track_caller(...GFP_USER | __GFP_NOWARN);
That GFP_USER looks wrong. It shouldn't matter _much_ in practice, but
it's allocating kernel memory with GFP_USER.
prev parent reply other threads:[~2025-09-25 15:37 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-08 20:12 [PATCH] x86/sgx: Replace kmalloc() + copy_from_user() with memdup_user() Thorsten Blum
2025-09-10 17:12 ` Jarkko Sakkinen
2025-09-21 9:59 ` kernel test robot
2025-09-22 13:18 ` Thorsten Blum
2025-09-25 15:37 ` Dave Hansen [this message]
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