arch/x86/include/asm/uaccess_32.h:212: copy_from_user() buffer sizeis not provably correct

From: Christian Kujau
Date: Sat Mar 05 2011 - 21:25:32 EST


Hi,

while trying to compile 2.6.38-rc7 with randconfigs, I noticed
compilation would sometimes fail with:

-------------------------------------------------------
In file included from
/usr/local/src/linux-2.6-git/arch/x86/include/asm/uaccess.h:571,
from /usr/local/src/linux-2.6-git/include/net/checksum.h:25,
from
/usr/local/src/linux-2.6-git/include/linux/skbuff.h:28,
from
/usr/local/src/linux-2.6-git/include/linux/if_ether.h:126,
from
/usr/local/src/linux-2.6-git/include/linux/netdevice.h:29,
from
/usr/local/src/linux-2.6-git/net/packet/af_packet.c:58:
In function 'copy_from_user',
inlined from 'packet_getsockopt' at
/usr/local/src/linux-2.6-git/net/packet/af_packet.c:2137:
/usr/local/src/linux-2.6-git/arch/x86/include/asm/uaccess_32.h:212: error:
call to 'copy_from_user_overflow' declared with attribute error:
copy_from_user() buffer size is not provably correct
-------------------------------------------------------

A few failed configs (and compile logs) are here:

http://nerdbynature.de/bits/2.6.38-rc7/copy_from_user/

I've seen a thread[0] in Jan 2010, dealing with copy_from_user, but don't
know if that is the reason for these compile failures.

It's not really an issue for me, since they're randconfigs anyway so might
not even be runnable on real hardware, but thought it would be worth to
mention anyway.

Thanks,
Christian.

[0] http://lkml.org/lkml/2010/1/5/75
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