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From: sashiko-bot@kernel.org
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Cc: kexec@lists.infradead.org, ruanjinjie@huawei.com
Subject: Re: [PATCH v6 14/14] crash: Fix TOCTOU race in crash memory range collection
Date: Mon, 21 Sep 2026 09:25:27 +0000	[thread overview]
Message-ID: <20260921092528.17C231F000FF@smtp.kernel.org> (raw)
In-Reply-To: <20260921090450.807575-15-ruanjinjie@huawei.com>

> The crash kernel ELF core header construction counts system memory
> ranges via `arch_get_system_nr_ranges()`, allocates the crash_mem
> buffer, and then populates it via `arch_crash_populate_cmem()`.
> This sequence has a time-of-check-to-time-of-use (TOCTOU) race with
> memory hotplug: a concurrent hotplug event between the count
> and populate steps can increase the number of ranges beyond the allocated
> capacity, causing an out-of-bounds write. If the event triggers
> memblock_double_array(), the memblock array can be freed and reallocated
> during iteration, leading to a use-after-free.
> 
> Protect the entire range collection with device_hotplug_lock. Since
> the hotplug notification path already holds that lock, add a lockless
> helper, crash_get_memory_ranges_nolock(), for use there. The regular
> crash_get_memory_ranges() acquires the lock and calls the helper.
> 
> [ ... ]
> Fixes: 3751e728cef2 ("arm64: kexec_file: add crash dump support")
> Fixes: 8acea455fafa ("RISC-V: Support for kexec_file on panic")
> Fixes: 1bcca8620a91 ("LoongArch: Add crash dump support for kexec_file")
> Link: https://sashiko.dev/#/patchset/20260729031235.2840255-1-ruanjinjie%40huawei.com
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260921090450.807575-1-ruanjinjie@huawei.com?part=14



WARNING: multiple messages have this Message-ID (diff)
From: sashiko-bot@kernel.org
To: kees@kernel.org, piliu@redhat.com, npiggin@gmail.com,
	mpe@ellerman.id.au, me@linux.beauty, bgwin@google.com,
	mingo@redhat.com, x86@kernel.org, baoquan.he@linux.dev,
	guodongtai@kylinos.cn, leitao@debian.org,
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	maddy@linux.ibm.com
Cc: kexec@lists.infradead.org, ruanjinjie@huawei.com
Subject: Re: [PATCH v6 14/14] crash: Fix TOCTOU race in crash memory range collection
Date: Mon, 21 Sep 2026 09:25:27 +0000	[thread overview]
Message-ID: <20260921092528.17C231F000FF@smtp.kernel.org> (raw)
In-Reply-To: <20260921090450.807575-15-ruanjinjie@huawei.com>

> The crash kernel ELF core header construction counts system memory
> ranges via `arch_get_system_nr_ranges()`, allocates the crash_mem
> buffer, and then populates it via `arch_crash_populate_cmem()`.
> This sequence has a time-of-check-to-time-of-use (TOCTOU) race with
> memory hotplug: a concurrent hotplug event between the count
> and populate steps can increase the number of ranges beyond the allocated
> capacity, causing an out-of-bounds write. If the event triggers
> memblock_double_array(), the memblock array can be freed and reallocated
> during iteration, leading to a use-after-free.
> 
> Protect the entire range collection with device_hotplug_lock. Since
> the hotplug notification path already holds that lock, add a lockless
> helper, crash_get_memory_ranges_nolock(), for use there. The regular
> crash_get_memory_ranges() acquires the lock and calls the helper.
> 
> [ ... ]
> Fixes: 3751e728cef2 ("arm64: kexec_file: add crash dump support")
> Fixes: 8acea455fafa ("RISC-V: Support for kexec_file on panic")
> Fixes: 1bcca8620a91 ("LoongArch: Add crash dump support for kexec_file")
> Link: https://sashiko.dev/#/patchset/20260729031235.2840255-1-ruanjinjie%40huawei.com
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260921090450.807575-1-ruanjinjie@huawei.com?part=14


  reply	other threads:[~2026-09-21  9:25 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-21  9:04 [PATCH v6 00/14] crash: Fix several bugs Jinjie Ruan
2026-09-21  9:04 ` [PATCH v6 01/14] kexec: Fix CMA segment address translation with non-zero text_offset Jinjie Ruan
2026-09-21  9:17   ` sashiko-bot
2026-09-21  9:04 ` [PATCH v6 02/14] kexec: Record allocated CMA pages to fix release size mismatch Jinjie Ruan
2026-09-21  9:14   ` sashiko-bot
2026-09-21  9:04 ` [PATCH v6 03/14] kexec: Extract kexec_free_segment_cma() from kimage_free_cma() Jinjie Ruan
2026-09-21  9:13   ` sashiko-bot
2026-09-21  9:13     ` sashiko-bot
2026-09-21  9:04 ` [PATCH v6 04/14] arm64: kexec_file: Fix CMA page leaks in segment placement retry loops Jinjie Ruan
2026-09-21  9:18   ` sashiko-bot
2026-09-21  9:04 ` [PATCH v6 05/14] arm64: kexec_file: Fix elf_headers memory leak in retry loop Jinjie Ruan
2026-09-21  9:15   ` sashiko-bot
2026-10-10 20:00   ` Catalin Marinas
2026-09-21  9:04 ` [PATCH v6 06/14] LoongArch: kexec_file: Fix CMA page leaks in segment placement retry loops Jinjie Ruan
2026-09-21  9:13   ` sashiko-bot
2026-09-21  9:13     ` sashiko-bot
2026-09-21  9:04 ` [PATCH v6 07/14] LoongArch: kexec_file: Fix elf_headers memory leak in retry loop Jinjie Ruan
2026-09-21  9:14   ` sashiko-bot
2026-09-21  9:04 ` [PATCH v6 08/14] LoongArch: kexec_file: Fix a modified_cmdline leak Jinjie Ruan
2026-09-21  9:15   ` sashiko-bot
2026-09-21  9:04 ` [PATCH v6 09/14] x86/crash: Fix massive out-of-bounds write on 32-bit Highmem Jinjie Ruan
2026-09-21  9:12   ` sashiko-bot
2026-09-21  9:12     ` sashiko-bot
2026-09-21  9:04 ` [PATCH v6 10/14] crash: Extract crash_get_memory_ranges() helper Jinjie Ruan
2026-09-21  9:19   ` sashiko-bot
2026-09-21  9:04 ` [PATCH v6 11/14] crash: Factor out crash_find_elfcorehdr() helper Jinjie Ruan
2026-09-21  9:17   ` sashiko-bot
2026-09-21  9:04 ` [PATCH v6 12/14] crash: Normalize the kexec_load elfcorehdr at load time Jinjie Ruan
2026-09-21  9:19   ` sashiko-bot
2026-09-21  9:04 ` [PATCH v6 13/14] driver core: Add device_hotplug_lock_assert_held() helper Jinjie Ruan
2026-09-21  9:18   ` sashiko-bot
2026-09-21  9:04 ` [PATCH v6 14/14] crash: Fix TOCTOU race in crash memory range collection Jinjie Ruan
2026-09-21  9:25   ` sashiko-bot [this message]
2026-09-21  9:25     ` sashiko-bot
2026-10-08  1:57 ` [PATCH v6 00/14] crash: Fix several bugs Jinjie Ruan
2026-10-08  3:26   ` Baoquan He
2026-10-08  6:42   ` Mike Rapoport

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