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

> 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 <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Borislav Petkov <[email protected]>
> Cc: Dave Hansen <[email protected]>
> Cc: "H. Peter Anvin" <[email protected]>
> Cc: "Mike Rapoport (Microsoft)" <[email protected]>
> Cc: Vishal Verma <[email protected]>
> Cc: Baoquan He <[email protected]>
> Cc: Chao Gao <[email protected]>
> Cc: Sean Christopherson <[email protected]>
> Cc: Eric DeVolder <[email protected]>
> Cc: Hari Bathini <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Cc: Sourabh Jain <[email protected]>
> Cc: [email protected]
> 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 <[email protected]>

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

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