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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Will Deacon <will@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Jan Kara <jack@suse.cz>, Minchan Kim <minchan@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	Vinayak Menon <vinmenon@codeaurora.org>,
	Hugh Dickins <hughd@google.com>,
	Android Kernel Team <kernel-team@android.com>
Subject: Re: [RFC PATCH 4/8] mm: Separate fault info out of 'struct vm_fault'
Date: Thu, 14 Jan 2021 13:11:12 -0800	[thread overview]
Message-ID: <CAHk-=wixswKjAPt0eEVSHqOQB9tBuO5FeqfyKyxFWyBLEG6EcQ@mail.gmail.com> (raw)
In-Reply-To: <20210114194129.GA13314@willie-the-truck>

On Thu, Jan 14, 2021 at 11:41 AM Will Deacon <will@kernel.org> wrote:
>
> Sure enough, an arm64 defconfig builds perfectly alright with that change,
> but it really shouldn't. I'm using clang 11.0.5, so I had another go with
> GCC 9.2.1 and bang:

Ok, looks like a clang bug, but a reasonably benign one.

As long as we have sufficient coverage with gcc, we'll get error
reporting in a timely manner for any new incorrect assignments, so I
think we can do that constant anonymous struct even if it does mean
that clang might let some bad cases through (I personally use gcc for
build testing, and then clang for building my boot kernels, so I'd
catch anything x86-64 allmodconfig in my build tests).

And keeping it unnamed it would avoid a lot of noisy churn..

             Linus

WARNING: multiple messages have this Message-ID (diff)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Will Deacon <will@kernel.org>
Cc: Jan Kara <jack@suse.cz>, Minchan Kim <minchan@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>,
	Vinayak Menon <vinmenon@codeaurora.org>,
	Hugh Dickins <hughd@google.com>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Android Kernel Team <kernel-team@android.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC PATCH 4/8] mm: Separate fault info out of 'struct vm_fault'
Date: Thu, 14 Jan 2021 13:11:12 -0800	[thread overview]
Message-ID: <CAHk-=wixswKjAPt0eEVSHqOQB9tBuO5FeqfyKyxFWyBLEG6EcQ@mail.gmail.com> (raw)
In-Reply-To: <20210114194129.GA13314@willie-the-truck>

On Thu, Jan 14, 2021 at 11:41 AM Will Deacon <will@kernel.org> wrote:
>
> Sure enough, an arm64 defconfig builds perfectly alright with that change,
> but it really shouldn't. I'm using clang 11.0.5, so I had another go with
> GCC 9.2.1 and bang:

Ok, looks like a clang bug, but a reasonably benign one.

As long as we have sufficient coverage with gcc, we'll get error
reporting in a timely manner for any new incorrect assignments, so I
think we can do that constant anonymous struct even if it does mean
that clang might let some bad cases through (I personally use gcc for
build testing, and then clang for building my boot kernels, so I'd
catch anything x86-64 allmodconfig in my build tests).

And keeping it unnamed it would avoid a lot of noisy churn..

             Linus

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2021-01-14 21:12 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-14 17:59 [PATCH v3 0/8] Create 'old' ptes for faultaround mappings on arm64 with hardware access flag Will Deacon
2021-01-14 17:59 ` Will Deacon
2021-01-14 17:59 ` [PATCH v3 1/8] mm: Cleanup faultaround and finish_fault() codepaths Will Deacon
2021-01-14 17:59   ` Will Deacon
2021-02-09 20:24   ` Guenter Roeck
2021-02-09 20:24     ` Guenter Roeck
2021-02-10 11:44     ` Will Deacon
2021-02-10 11:44       ` Will Deacon
2021-02-10 14:57       ` Guenter Roeck
2021-02-10 14:57         ` Guenter Roeck
2021-01-14 17:59 ` [PATCH v3 2/8] mm: Allow architectures to request 'old' entries when prefaulting Will Deacon
2021-01-14 17:59   ` Will Deacon
2021-01-14 17:59 ` [PATCH v3 3/8] arm64: mm: Implement arch_wants_old_prefaulted_pte() Will Deacon
2021-01-14 17:59   ` Will Deacon
2021-01-14 17:59 ` [RFC PATCH 4/8] mm: Separate fault info out of 'struct vm_fault' Will Deacon
2021-01-14 18:16   ` Linus Torvalds
2021-01-14 18:16     ` Linus Torvalds
2021-01-14 18:16     ` Linus Torvalds
2021-01-14 19:00     ` Will Deacon
2021-01-14 19:00       ` Will Deacon
2021-01-14 19:09       ` Linus Torvalds
2021-01-14 19:09         ` Linus Torvalds
2021-01-14 19:09         ` Linus Torvalds
2021-01-14 19:41         ` Will Deacon
2021-01-14 19:41           ` Will Deacon
2021-01-14 20:09           ` Nick Desaulniers
2021-01-14 20:09             ` Nick Desaulniers
2021-01-14 20:09             ` Nick Desaulniers
2021-01-14 21:11           ` Linus Torvalds [this message]
2021-01-14 21:11             ` Linus Torvalds
2021-01-14 21:11             ` Linus Torvalds
2021-01-15  9:23             ` Will Deacon
2021-01-15  9:23               ` Will Deacon
2021-01-15 21:32               ` Linus Torvalds
2021-01-15 21:32                 ` Linus Torvalds
2021-01-15 21:32                 ` Linus Torvalds
2021-01-20  0:00                 ` Nick Desaulniers
2021-01-20  0:00                   ` Nick Desaulniers
2021-01-20  0:00                   ` Nick Desaulniers
2021-01-14 17:59 ` [RFC PATCH 5/8] mm: Pass 'address' to map to do_set_pte() and drop FAULT_FLAG_PREFAULT Will Deacon
2021-01-14 17:59   ` Will Deacon
2021-01-14 18:17   ` Linus Torvalds
2021-01-14 18:17     ` Linus Torvalds
2021-01-14 18:17     ` Linus Torvalds
2021-01-15 10:24     ` Will Deacon
2021-01-15 10:24       ` Will Deacon
2021-01-14 17:59 ` [RFC PATCH 6/8] mm: Avoid modifying vmf.info.address in __collapse_huge_page_swapin() Will Deacon
2021-01-14 17:59   ` Will Deacon
2021-01-14 17:59 ` [RFC PATCH 7/8] mm: Use static initialisers for 'info' field of 'struct vm_fault' Will Deacon
2021-01-14 17:59   ` Will Deacon
2021-01-14 17:59 ` [RFC PATCH 8/8] mm: Mark 'info' field of 'struct vm_fault' as 'const' Will Deacon
2021-01-14 17:59   ` Will Deacon

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