linux-next: build failure after merge of the btrfs tree (Was: Re: linux-next: build failure after merge of the kspp tree)

[Stephen Rothwell]

Hi all,

On Tue, 25 Jan 2022 15:07:30 +0100 David Sterba <dsterba@xxxxxxx> wrote:
>
> On Tue, Jan 25, 2022 at 11:57:57AM +1100, Stephen Rothwell wrote:
> > 
> > After merging the kspp tree, today's linux-next build (x86_64
> > allmodconfig) failed like this:
> > 
> > In file included from include/linux/string.h:253,
> >                  from include/linux/bitmap.h:11,
> >                  from include/linux/cpumask.h:12,
> >                  from arch/x86/include/asm/cpumask.h:5,
> >                  from arch/x86/include/asm/msr.h:11,
> >                  from arch/x86/include/asm/processor.h:22,
> >                  from arch/x86/include/asm/cpufeature.h:5,
> >                  from arch/x86/include/asm/thread_info.h:53,
> >                  from include/linux/thread_info.h:60,
> >                  from arch/x86/include/asm/preempt.h:7,
> >                  from include/linux/preempt.h:78,
> >                  from include/linux/spinlock.h:55,
> >                  from include/linux/wait.h:9,
> >                  from include/linux/mempool.h:8,
> >                  from include/linux/bio.h:8,
> >                  from fs/btrfs/ioctl.c:7:
> > In function 'fortify_memcpy_chk',
> >     inlined from 'btrfs_ioctl_encoded_write' at fs/btrfs/ioctl.c:5082:3:
> > include/linux/fortify-string.h:316:25: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
> >   316 |                         __write_overflow_field(p_size_field, size);
> >       |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > include/linux/fortify-string.h:324:25: error: call to '__read_overflow2_field' declared with attribute warning: detected read beyond size of field (2nd parameter); maybe use struct_group()? [-Werror=attribute-warning]
> >   324 |                         __read_overflow2_field(q_size_field, size);
> >       |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > cc1: all warnings being treated as errors
> > 
> > Caused by commit
> > 
> >   602670289b69 ("fortify: Detect struct member overflows in memcpy() at compile-time")
> > 
> > interacting with commit
> > 
> >   504e1ebb6316 ("btrfs: add BTRFS_IOC_ENCODED_WRITE")
> > 
> > from the btrfs tree.
> > 
> > I applied the following hack:
> > 
> > From: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> > Date: Tue, 25 Jan 2022 11:47:17 +1100
> > Subject: [PATCH] fix up for "btrfs: add BTRFS_IOC_ENCODED_WRITE"
> > 
> > Signed-off-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> > ---
> >  fs/btrfs/ioctl.c | 11 ++++++++---
> >  1 file changed, 8 insertions(+), 3 deletions(-)
> > 
> > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> > index 73ad918a05a9..d34620034f8e 100644
> > --- a/fs/btrfs/ioctl.c
> > +++ b/fs/btrfs/ioctl.c
> > @@ -5079,9 +5079,14 @@ static int btrfs_ioctl_encoded_write(struct file *file, void __user *argp,
> >  		}
> >  		args.iov = compat_ptr(args32.iov);
> >  		args.iovcnt = args32.iovcnt;
> > -		memcpy(&args.offset, &args32.offset,
> > -		       sizeof(args) -
> > -		       offsetof(struct btrfs_ioctl_encoded_io_args, offset));
> > +		args.offset = args32.offset;
> > +		args.flags = args32.flags;
> > +		args.len = args32.len;
> > +		args.unencoded_len = args32.unencoded_len;
> > +		args.unencoded_offset = args32.unencoded_offset;
> > +		args.compression = args32.compression;
> > +		args.encryption = args32.encryption;
> > +		memcpy(args.reserved, args32.reserved, sizeof(args.reserved));
> >  #else
> >  		return -ENOTTY;
> >  #endif  
> 
> Thanks, the patchset is still in progress so I'll apply this a fixup
> until the patch gets updated.

This has come back today ... presumably the hack was removed but the
original patch was not fixed.

I have used the btrfs tree from next-20220210 for today.

-- 
Cheers,
Stephen Rothwell

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