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From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>,
	Breno Leitao <leitao@debian.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>,
	Naoya Horiguchi <nao.horiguchi@gmail.com>,
	Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Alexandre Ghiti <alex@ghiti.fr>, SJ Park <sj@kernel.org>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-riscv@lists.infradead.org, kernel-team@meta.com
Subject: Re: [PATCH v2] tools/mm: add hwpoison-panic tool
Date: Mon, 7 Sep 2026 14:42:06 +0200	[thread overview]
Message-ID: <1ecffc76-55da-4831-8f21-04c97ce90ec8@kernel.org> (raw)
In-Reply-To: <20260829193758.b251f3c89f8201bdc585a305@linux-foundation.org>

On 8/30/26 04:37, Andrew Morton wrote:
> On Mon, 03 Aug 2026 04:31:20 -0700 Breno Leitao <leitao@debian.org> wrote:
> 
>> Add a tool that enables the vm.panic_on_unrecoverable_memory_failure
>> sysctl, picks a kernel-owned PFN and writes its physical address to
>> hard_offline_page.  Three page kinds are selectable with -k: rodata
>> (default), slab or pgtable. In all cases the host should panic.
>>
>> Example:
>>
>>         # ./hwpoison-panic -k slab --yes-panic-my-kernel
>>         injecting hwpoison at phys 0x100032000 (pfn 0x100032, kind=slab)
>>         expecting kernel panic: 'Memory failure: <pfn>: unrecoverable page'
>>
>> In dmesg, you will see:
>>
>>         Memory failure: 0x100032: unhandlable page.
>>         Memory failure: 0x100032: recovery action for reserved kernel page: Ignored
>>         Kernel panic - not syncing: Memory failure: 0x100032: unrecoverable page
>>
>> This lives in tools/mm rather than selftests/mm because every successful
>> run crashes the machine, which is not something to run from CI.
> 
> I wonder if we can fix this.  Add a knob which tells the kernel not to
> panic/oops/crash/etc.  Instead it sends a message "i tried to crash but
> you told me not to" and proceeds.
> 
> Set that knob around your hwpoison-panic tool and voila, it's now a
> selftest.

We just shot down a random "kernel-owned PFN" (marking it hwpoison etc).

That's really not something you want to do from a selftest.

You'd need some kind of hwpoison simulation mode.

-- 
Cheers,

David


WARNING: multiple messages have this Message-ID (diff)
From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>,
	Breno Leitao <leitao@debian.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>,
	Naoya Horiguchi <nao.horiguchi@gmail.com>,
	Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Alexandre Ghiti <alex@ghiti.fr>, SJ Park <sj@kernel.org>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-riscv@lists.infradead.org, kernel-team@meta.com
Subject: Re: [PATCH v2] tools/mm: add hwpoison-panic tool
Date: Mon, 7 Sep 2026 14:42:06 +0200	[thread overview]
Message-ID: <1ecffc76-55da-4831-8f21-04c97ce90ec8@kernel.org> (raw)
In-Reply-To: <20260829193758.b251f3c89f8201bdc585a305@linux-foundation.org>

On 8/30/26 04:37, Andrew Morton wrote:
> On Mon, 03 Aug 2026 04:31:20 -0700 Breno Leitao <leitao@debian.org> wrote:
> 
>> Add a tool that enables the vm.panic_on_unrecoverable_memory_failure
>> sysctl, picks a kernel-owned PFN and writes its physical address to
>> hard_offline_page.  Three page kinds are selectable with -k: rodata
>> (default), slab or pgtable. In all cases the host should panic.
>>
>> Example:
>>
>>         # ./hwpoison-panic -k slab --yes-panic-my-kernel
>>         injecting hwpoison at phys 0x100032000 (pfn 0x100032, kind=slab)
>>         expecting kernel panic: 'Memory failure: <pfn>: unrecoverable page'
>>
>> In dmesg, you will see:
>>
>>         Memory failure: 0x100032: unhandlable page.
>>         Memory failure: 0x100032: recovery action for reserved kernel page: Ignored
>>         Kernel panic - not syncing: Memory failure: 0x100032: unrecoverable page
>>
>> This lives in tools/mm rather than selftests/mm because every successful
>> run crashes the machine, which is not something to run from CI.
> 
> I wonder if we can fix this.  Add a knob which tells the kernel not to
> panic/oops/crash/etc.  Instead it sends a message "i tried to crash but
> you told me not to" and proceeds.
> 
> Set that knob around your hwpoison-panic tool and voila, it's now a
> selftest.

We just shot down a random "kernel-owned PFN" (marking it hwpoison etc).

That's really not something you want to do from a selftest.

You'd need some kind of hwpoison simulation mode.

-- 
Cheers,

David

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  reply	other threads:[~2026-09-07 12:42 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-03 11:31 [PATCH v2] tools/mm: add hwpoison-panic tool Breno Leitao
2026-08-03 11:31 ` Breno Leitao
2026-08-13  7:32 ` Miaohe Lin
2026-08-13  7:32   ` Miaohe Lin
2026-08-13 10:19   ` Breno Leitao
2026-08-13 10:19     ` Breno Leitao
2026-08-30  2:37 ` Andrew Morton
2026-08-30  2:37   ` Andrew Morton
2026-09-07 12:42   ` David Hildenbrand (Arm) [this message]
2026-09-07 12:42     ` David Hildenbrand (Arm)

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