From: Michael Cree <mcree@orcon.net.nz>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Peter Xu <peterx@redhat.com>,
linux-arch@vger.kernel.org, linux-alpha@vger.kernel.org,
Richard Henderson <richard.henderson@linaro.org>
Subject: Re: [RFC][PATCHSET] VM_FAULT_RETRY fixes
Date: Thu, 2 Feb 2023 21:54:35 +1300 [thread overview]
Message-ID: <Y9t6Swqt+A9noVIf@creeky> (raw)
In-Reply-To: <Y9te+4n4ajSF++Ex@ZenIV>
On Thu, Feb 02, 2023 at 06:58:03AM +0000, Al Viro wrote:
> Other bugs in the same area:
> * we ought to compare address with VMALLOC_START,
> not TASK_SIZE.
> * we ought to do that *before* checking for
> kernel threads/pagefault_disable() being in effect.
>
> Wait a minute - pgd_present() on alpha has become constant 1
> since a73c948952cc "alpha: use pgtable-nopud instead of 4level-fixup"
>
> So that thing had been completely broken for 3 years and nobody
> had noticed.
I have never noticed because I haven't been able to run a 5.9 or
newer kernel on Alpha reliably so have been running a 5.8 kernel
for quite some time. Bad commit is about
25788738eb9ce46fe6a0fd84a3ceef5c795d41f0 but bisection proved very
difficult because the bug might only show up once per day (memory
corruption in user space causing gcc in big long builds to ICE
reporting corrupted structures, or similar) and so could never be
entirely sure a kernel marked as good was truly good in bisection
and went wrong a number of times. There is a good possibility the bad
commit is one of facdaa917c4d5a376d or 25788738eb9ce46fe6.
Cheers,
Michael.
next prev parent reply other threads:[~2023-02-02 8:54 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-31 20:02 [RFC][PATCHSET] VM_FAULT_RETRY fixes Al Viro
2023-01-31 20:03 ` [PATCH 01/10] alpha: fix livelock in uaccess Al Viro
2023-03-07 0:48 ` patchwork-bot+linux-riscv
2023-01-31 20:03 ` [PATCH 02/10] hexagon: " Al Viro
2023-02-10 2:59 ` Brian Cain
2023-01-31 20:04 ` [PATCH 03/10] ia64: " Al Viro
2023-01-31 20:04 ` [PATCH 04/10] m68k: " Al Viro
2023-02-05 6:18 ` Finn Thain
2023-02-05 18:51 ` Linus Torvalds
2023-02-07 3:07 ` Finn Thain
2023-02-05 20:39 ` Al Viro
2023-02-05 20:41 ` Linus Torvalds
2023-02-06 12:08 ` Geert Uytterhoeven
2023-01-31 20:05 ` [PATCH 05/10] microblaze: " Al Viro
2023-01-31 20:05 ` [PATCH 06/10] nios2: " Al Viro
2023-01-31 20:06 ` [PATCH 07/10] openrisc: " Al Viro
2023-01-31 20:06 ` [PATCH 08/10] parisc: " Al Viro
2023-02-06 16:58 ` Helge Deller
2023-02-28 17:34 ` Al Viro
2023-02-28 15:22 ` Guenter Roeck
2023-02-28 19:18 ` Michael Schmitz
2023-01-31 20:06 ` [PATCH 09/10] riscv: " Al Viro
2023-02-06 20:06 ` Björn Töpel
2023-02-07 16:11 ` Geert Uytterhoeven
2023-01-31 20:07 ` [PATCH 10/10] sparc: " Al Viro
2023-01-31 20:24 ` [RFC][PATCHSET] VM_FAULT_RETRY fixes Linus Torvalds
2023-01-31 21:10 ` Al Viro
2023-01-31 21:19 ` Linus Torvalds
2023-01-31 21:49 ` Al Viro
2023-02-01 0:00 ` Linus Torvalds
2023-02-01 19:48 ` Peter Xu
2023-02-01 22:18 ` Al Viro
2023-02-02 0:57 ` Al Viro
2023-02-02 22:56 ` Peter Xu
2023-02-04 0:26 ` Al Viro
2023-02-05 5:10 ` Al Viro
2023-02-01 8:21 ` Helge Deller
2023-02-01 19:51 ` Linus Torvalds
2023-02-02 6:58 ` Al Viro
2023-02-02 8:54 ` Michael Cree [this message]
2023-02-02 9:56 ` John Paul Adrian Glaubitz
2023-02-02 15:20 ` Al Viro
2023-02-02 20:20 ` Al Viro
2023-02-02 20:34 ` Linus Torvalds
2023-02-01 10:50 ` Mark Rutland
2023-02-06 12:08 ` Geert Uytterhoeven
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