From: Guenter Roeck <linux@roeck-us.net>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-arch@vger.kernel.org, linux-alpha@vger.kernel.org,
linux-ia64@vger.kernel.org, linux-hexagon@vger.kernel.org,
linux-m68k@lists.linux-m68k.org, Michal Simek <monstr@monstr.eu>,
Dinh Nguyen <dinguyen@kernel.org>,
openrisc@lists.librecores.org, linux-parisc@vger.kernel.org,
linux-riscv@lists.infradead.org, sparclinux@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 08/10] parisc: fix livelock in uaccess
Date: Tue, 28 Feb 2023 07:22:36 -0800 [thread overview]
Message-ID: <20230228152236.GA4088022@roeck-us.net> (raw)
In-Reply-To: <Y9l0w4M91DwYLO3N@ZenIV>
On Tue, Jan 31, 2023 at 08:06:27PM +0000, Al Viro wrote:
> parisc equivalent of 26178ec11ef3 "x86: mm: consolidate VM_FAULT_RETRY handling"
> If e.g. get_user() triggers a page fault and a fatal signal is caught, we might
> end up with handle_mm_fault() returning VM_FAULT_RETRY and not doing anything
> to page tables. In such case we must *not* return to the faulting insn -
> that would repeat the entire thing without making any progress; what we need
> instead is to treat that as failed (user) memory access.
>
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> ---
> arch/parisc/mm/fault.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c
> index 869204e97ec9..bb30ff6a3e19 100644
> --- a/arch/parisc/mm/fault.c
> +++ b/arch/parisc/mm/fault.c
> @@ -308,8 +308,11 @@ void do_page_fault(struct pt_regs *regs, unsigned long code,
>
> fault = handle_mm_fault(vma, address, flags, regs);
>
> - if (fault_signal_pending(fault, regs))
> + if (fault_signal_pending(fault, regs)) {
> + if (!user_mode(regs))
> + goto no_context;
0-day rightfully complains that this leaves 'msg' uninitialized.
arch/parisc/mm/fault.c:427 do_page_fault() error: uninitialized symbol 'msg'
Guenter
> return;
> + }
>
> /* The fault is fully completed (including releasing mmap lock) */
> if (fault & VM_FAULT_COMPLETED)
next prev parent reply other threads:[~2023-02-28 15:22 UTC|newest]
Thread overview: 55+ 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 18:26 ` Helge Deller
2023-02-28 19:14 ` Al Viro
2023-02-28 19:32 ` Helge Deller
2023-02-28 20:00 ` Helge Deller
2023-02-28 20:22 ` Helge Deller
2023-02-28 22:57 ` Al Viro
2023-03-01 4:00 ` Helge Deller
2023-03-02 17:53 ` Al Viro
2023-02-28 15:22 ` Guenter Roeck [this message]
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
2023-02-04 0:47 ` [loongarch oddities] " 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
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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