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From: Andrew Morton <akpm@linux-foundation.org>
To: 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>,
	david@kernel.org, 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: Sat, 29 Aug 2026 19:37:58 -0700	[thread overview]
Message-ID: <20260829193758.b251f3c89f8201bdc585a305@linux-foundation.org> (raw)
In-Reply-To: <20260803-memory_failure_rewrite_test-v2-1-ed020ce42129@debian.org>

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.

Wondering if we can sneakily use fault-injection to do this.  Add a new
i_should_crash_now() and use fault-injection to make this function
"fail", by returning zero.  Or something else.



WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: 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>,
	david@kernel.org, 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: Sat, 29 Aug 2026 19:37:58 -0700	[thread overview]
Message-ID: <20260829193758.b251f3c89f8201bdc585a305@linux-foundation.org> (raw)
In-Reply-To: <20260803-memory_failure_rewrite_test-v2-1-ed020ce42129@debian.org>

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.

Wondering if we can sneakily use fault-injection to do this.  Add a new
i_should_crash_now() and use fault-injection to make this function
"fail", by returning zero.  Or something else.


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http://lists.infradead.org/mailman/listinfo/linux-riscv

  parent reply	other threads:[~2026-08-30  2:38 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 [this message]
2026-08-30  2:37   ` Andrew Morton
2026-09-07 12:42   ` David Hildenbrand (Arm)
2026-09-07 12:42     ` David Hildenbrand (Arm)

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