Hi all, On Wed, 29 Feb 2012 10:52:10 +1100 Stephen Rothwell wrote: > > On Tue, 28 Feb 2012 13:37:24 +0000 Matt Fleming wrote: > > > > From: Matt Fleming > > > > We may need to convert the endianness of the data we read from/write > > to 'buf', so let's use {get,put}_unaligned_le32() to do that. Failure > > to do so can result in accessing invalid memory, leading to a > > segfault. Stephen Rothwell noticed this bug while cross-building an > > x86_64 allmodconfig kernel on PowerPC. > > > > We need to read from and write to 'buf' a byte at a time otherwise > > it's possible we'll perform an unaligned access, which can lead to bus > > errors when cross-building an x86 kernel on risc architectures. > > > > Cc: H. Peter Anvin > > Cc: Nick Bowler > > Tested-by: Stephen Rothwell > > Reported-by: Stephen Rothwell > > Signed-off-by: Matt Fleming > > Just to be absolutely clear, I have not yet tested this version of the > patch and also this fixes a problem with cross building Linus' tree (i.e. > this is a regression with cross building introduced in v3.3-rc1). OK, I tried just that patch on top of Linus' tree and obviously that didn't work :-) so I pulled the x86/build branch from the tip tree into my tree (which contained just Linus' tree of today (v3.3-rc5-97-g891003a)). and the build failed like this: arch/x86/boot/tools/build.c:36:22: error: asm/boot.h: No such file or directory The build is an ARCH=x86_64 defconfig with CONFIG_EFI_STUB=y. -- Cheers, Stephen Rothwell sfr@canb.auug.org.au