Hi Mark,
On Wed, Feb 1, 2023 at 11:52 AM Mark Rutland <mark.rutland@xxxxxxx> wrote:
On Tue, Jan 31, 2023 at 08:02:51PM +0000, Al Viro wrote:
On x86 it had been noticed and fixed back in 2014, in 26178ec11ef3 "x86:
mm: consolidate VM_FAULT_RETRY handling". Some of the other architectures
had it dealt with later - e.g. arm in 2017, the fix is 746a272e44141
"ARM: 8692/1: mm: abort uaccess retries upon fatal signal"; xtensa -
in 2021, the fix is 7b9acbb6aad4f "xtensa: fix uaccess-related livelock
in do_page_fault", etc.
However, it never had been done on a bunch of architectures - the
current mainline still has that bug on alpha, hexagon, itanic, m68k,
microblaze, nios2, openrisc, parisc, riscv and sparc (both sparc32 and
sparc64). Fixes are trivial, but I've no way to test them for most
of those architectures.
FWIW, when I fixed arm and arm64 back in 2017, I did report the issue here with
a test case (and again in 2021, with maintainers all explciitly Cc'd):
https://lore.kernel.org/lkml/20170822102527.GA14671@leverpostej/
https://lore.kernel.org/linux-arch/20210121123140.GD48431@C02TD0UTHF1T.local/
... so if anyone has access to those architectures, that test might be useful
for verifying the fix.
Thanks a lot! This showed the problem on m68k, and confirmed Al's fix.
I'll give it a try on a few more systems later...
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
