Re: [PATCH 5.10 000/286] 5.10.209-rc1 review

[Nathan Chancellor <nathan@kernel.org>]

On Fri, Jan 26, 2024 at 10:17:23AM -0800, Guenter Roeck wrote:
> On 1/26/24 09:51, Greg Kroah-Hartman wrote:
> > On Fri, Jan 26, 2024 at 08:46:42AM -0800, Guenter Roeck wrote:
> > > On 1/22/24 15:55, Greg Kroah-Hartman wrote:
> > > > This is the start of the stable review cycle for the 5.10.209 release.
> > > > There are 286 patches in this series, all will be posted as a response
> > > > to this one.  If anyone has any issues with these being applied, please
> > > > let me know.
> > > > 
> > > > Responses should be made by Wed, 24 Jan 2024 23:56:49 +0000.
> > > > Anything received after that time might be too late.
> > > > 
> > > [ ... ]
> > > 
> > > > zhenwei pi <pizhenwei@bytedance.com>
> > > >       virtio-crypto: implement RSA algorithm
> > > > 
> > > 
> > > Curious: Why was this (and its subsequent fixes) backported to v5.10.y ?
> > > It is quite beyond a bug fix. Also, unless I am really missing something,
> > > the series (or at least this patch) was not applied to v5.15.y, so we now
> > > have functionality in v5.10.y which is not in v5.15.y.
> > 
> > See the commit text, it was a dependency of a later fix and documented
> > as such.
> > 
> > Having it in 5.10 and not 5.15 is a bit odd, I agree, so patches are
> > gladly accepted :)
> > 
> 
> We reverted the entire series from the merge because it results in a build
> failure for us.
> 
> In file included from /home/groeck/src/linux-chromeos/drivers/crypto/virtio/virtio_crypto_akcipher_algs.c:10:
> In file included from /home/groeck/src/linux-chromeos/include/linux/mpi.h:21:
> In file included from /home/groeck/src/linux-chromeos/include/linux/scatterlist.h:5:
> In file included from /home/groeck/src/linux-chromeos/include/linux/string.h:293:
> /home/groeck/src/linux-chromeos/include/linux/fortify-string.h:512:4: error: call to __read_overflow2_field declared with 'warning' attribute: detected read beyond size of field (2nd parameter); maybe use struct_group()? [-Werror,-Wattribute-warning]
>                         __read_overflow2_field(q_size_field, size);

For what it's worth, this is likely self inflicted for chromeos-5.10,
which carries a revert of commit eaafc590053b ("fortify: Explicitly
disable Clang support") as commit c19861d34c003 ("CHROMIUM: Revert
"fortify: Explicitly disable Clang support""). I don't see the series
that added proper support for clang to fortify in 5.18 that ended with
commit 281d0c962752 ("fortify: Add Clang support") in that ChromeOS
branch, so this seems somewhat expected.

> I also see that upstream (starting with 6.1) when trying to build it with clang,
> so I guess it is one of those bug-for-bug compatibility things. I really have
> no idea what causes it, or why we don't see the problem when building
> chromeos-6.1 or chromeos-6.6, but (so far) only with chromeos-5.10 after
> merging 5.10.209 into it. Making things worse, the problem isn't _always_
> seen. Sometimes I can compile the file in 6.1.y without error, sometimes not.
> I have no idea what triggers the problem.

Have a .config that reproduces it on upstream? I have not personally
seen this warning in my build matrix nor has our continuous-integration
matrix (I don't see it in the warning output at the bottom but that
could have missed something for some reason) in 6.1:

https://github.com/ClangBuiltLinux/continuous-integration2/actions/runs/7662499796
https://github.com/ClangBuiltLinux/continuous-integration2/actions/runs/7662534888

Reverting this series from 5.10 seems reasonable given your other
comments but if there is still something to sort out upstream, I
definitely want to.

> Of course, on top of all that, the error message is completely useless.

Indeed, outstanding papercut unfortunately:
https://github.com/ClangBuiltLinux/linux/issues/1571

Cheers,
Nathan