linux-next: build failure after merge of the kspp tree

Stephen Rothwell
2022-01-25T03:53:47Z

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Hi all,

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@canb.auug.org.au>
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@canb.auug.org.au>
---
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
--
2.34.1

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Cheers,
Stephen Rothwell

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