[PATCH v4] ARM: mm: acquire mmap write lock around show_pte() for user faults

[Linus Walleij]

On Sat, Jul 25, 2026 at 4:10 AM Xie Yuanbin <xieyuanbin1 at huawei.com> wrote:
> On Sat, 25 Jul 2026 00:05:58 +0200, Linus Walleij wrote:
> > On Thu, 16 Jul 2026 09:40:22 +0800, Xie Yuanbin <xieyuanbin1 at huawei.com> wrote:

> >> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> >> Fixes: 6d021b724481 ("ARM: dump pgd, pmd and pte states on unhandled data abort faults")
> >> Depends-on: <20260629123349.134224-1-xieyuanbin1 at huawei.com>
> >> Depends-on: 59e4f3b45b96 ("ARM: ensure interrupts are enabled in __do_user_fault()")
> >
> > This looks a bit odd. I don't get the first fix tag, drop it.
>
> The first fix tag can be open as:
> Link: https://github.com/torvalds/linux/commit/1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
> Link: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
> It seems that a 12-character hash is no longer sufficient to index it. :)
>
> May I increase the number of hash characters or just drop it?

You still don't explain why you add this odd Fixes tag, which is
why I ask.

If your point is that this bug goes back before the start of git, then
just write that in the commit message, no-one will backport it
to 2.6.x.

> These tags are for the maintainers of the stable/LTS branches. Since
> the bug is very old (we discovered it in linux-5.10), they are likely to
> be backported to the LTS versions. However, the depends-on commits may
> not be merged to the LTS versions.

They will figure it out anyway, both Greg and Sasha are very clever
people with very clever scripts.

Yours,
Linus Walleij