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Date:   Fri, 8 Jan 2021 09:26:56 +0000
From:   Will Deacon <will@kernel.org>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Arnd Bergmann <arnd@kernel.org>,
        Russell King - ARM Linux admin <linux@armlinux.org.uk>,
        linux-toolchains@vger.kernel.org,
        Mark Rutland <mark.rutland@arm.com>,
        Theodore Ts'o <tytso@mit.edu>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Andreas Dilger <adilger.kernel@dilger.ca>,
        Ext4 Developers List <linux-ext4@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: Aarch64 EXT4FS inode checksum failures - seems to be weak memory
 ordering issues
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On Fri, Jan 08, 2021 at 10:21:54AM +0100, Peter Zijlstra wrote:
> On Thu, Jan 07, 2021 at 10:20:38PM +0100, Arnd Bergmann wrote:
> > On Thu, Jan 7, 2021 at 2:37 PM Russell King - ARM Linux admin
> 
> > > So, do we raise the minimum gcc version for the kernel as a whole to 5.1
> > > or just for aarch64?
> > 
> > I'd personally love to see gcc-5 as the global minimum version, as that
> > would let us finally use --std=gnu11 features instead of gnu89. [There are
> > a couple of useful features that are incompatible with gnu89, and
> > gnu99/gnu11 support in gcc didn't like the kernel sources]
> 
> +1 for raising the tree-wide minimum (again!). We actually have a bunch
> of work-arounds for 4.9 bugs we can get rid of as well.

We even just added another one for arm64 KVM! [1]

So yes, I'm in favour of leaving gcc 4.9 to rot as well, especially after
this ext4 debugging experience.

Will

[1] https://git.kernel.org/linus/9fd339a45be5