Re: [PATCH v3 08/12] mm: Add VM_CRASH_MARK

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Low] mm: VM_CRASH_MARK missing from ftrace mmflags VMA flag definitions
- [Low] mm: proc.rst missing documentation for 'cm' VmFlags mnemonic
--

commit 7b00e78975a449ed080eb0472f9ec80a85b781f6
Author: Jan Sebastian Götte <linux@jaseg.de>

mm: Add VM_CRASH_MARK

This commit adds a new VMA flag, VM_CRASH_MARK, to describe folios mapped
into a VMA to the kdump kernel through crash_memaction. The flag indicates
pages to be handled based on the cmdline param, such as secret or cache
pages.

> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> index c0d228036b8a6..880946edf4dfa 100644
> --- a/fs/proc/task_mmu.c
> +++ b/fs/proc/task_mmu.c
> @@ -1161,6 +1161,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
>  #endif
>  #ifdef CONFIG_64BIT
>  		[ilog2(VM_SEALED)] = "sl",
> +#endif
> +#ifdef CONFIG_CRASH_MEMACTION
> +		[ilog2(VM_CRASH_MARK)] = "cm",

[Severity: Low]
Since this adds the new cm mnemonic to the smaps output in show_smap_vma_flags(),
shouldn't this also be documented in Documentation/filesystems/proc.rst so users
reading the smaps file can understand what the string means?

>  #endif
>  	};
>  	size_t i;
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index b9ed4f569b75f..4ffe6350f8655 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
[ ... ]
> @@ -526,6 +530,11 @@ enum {
>  #define VM_ALLOW_ANY_UNCACHED	VM_NONE
>  #define VM_SEALED		VM_NONE
>  #endif
> +#ifdef CONFIG_CRASH_MEMACTION
> +#define VM_CRASH_MARK		INIT_VM_FLAG(CRASH_MARK)

[Severity: Low]
When defining a new VMA flag here, does it also need to be registered in the
__def_vmaflag_names array in include/trace/events/mmflags.h?

If it is omitted, tracing tools capturing mmap or madvise events might output
an unknown hexadecimal bit instead of the human-readable crash_mark flag.

> +#else
> +#define VM_CRASH_MARK		VM_NONE
> +#endif

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260928-crash-memaction-upstream-20260921-v3-0-e511e9ee2329@jaseg.de?part=8