Re: [PATCH v5 09/17] x86/crash: Fix massive out-of-bounds write on 32-bit Highmem
From: sashiko-bot@kernel.org
Date: 2026-09-18 10:16:40
Also in:
driver-core, kexec, linux-fsdevel, linux-mm, lkml, loongarch
On 32-bit x86 systems with HIGHMEM, kmap_local_page() only maps a single
4KB page. However, the elfcorehdr segment can span several pages (up to
hundreds of kilobytes).
The original code blindly copies 'elfsz' bytes at once via
memcpy_flushcache(), overwriting adjacent fixmap entries or critical
virtual addresses.
Fix this by copying the new elfcorehdr page by page.
Cc: Thomas Gleixner <tglx@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Chao Gao <redacted>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Eric DeVolder <redacted>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Sourabh Jain <redacted>
Cc: stable@vger.kernel.org
Fixes: ea53ad9cf73b ("x86/crash: add x86 crash hotplug support")
Link: https://sashiko.dev/#/patchset/20260907125404.922123-1-ruanjinjie%40huawei.com
Signed-off-by: Jinjie Ruan <redacted>Sashiko has reviewed this patch and found no issues. It looks great! -- Sashiko AI review · https://sashiko.dev/#/patchset/20260918100442.3841135-1-ruanjinjie@huawei.com?part=9