Re: [PATCH v5 09/17] x86/crash: Fix massive out-of-bounds write on 32-bit Highmem

[sashiko-bot]

> 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@xxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxxxx>
> Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
> Cc: "Mike Rapoport (Microsoft)" <rppt@xxxxxxxxxx>
> Cc: Vishal Verma <vishal.l.verma@xxxxxxxxx>
> Cc: Baoquan He <baoquan.he@xxxxxxxxx>
> Cc: Chao Gao <chao.gao@xxxxxxxxx>
> Cc: Sean Christopherson <seanjc@xxxxxxxxxx>
> Cc: Eric DeVolder <eric.devolder@xxxxxxxxxx>
> Cc: Hari Bathini <hbathini@xxxxxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Sourabh Jain <sourabhjain@xxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> 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 <ruanjinjie@xxxxxxxxxx>

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

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260918100442.3841135-1-ruanjinjie@xxxxxxxxxx?part=9