From: Michal Nazarewicz Date: Tue, 12 Nov 2013 23:11:42 +0000 (-0800) Subject: drivers: w1: make w1_slave::flags long to avoid memory corruption X-Git-Tag: v3.13-rc1~106^2~5 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bb67093796a41e0f2601f5c0022fd8873ed59fee;p=pandora-kernel.git drivers: w1: make w1_slave::flags long to avoid memory corruption On architectures where long is more then 32 bits, modifying a 32-bit field with set_bit (and other atomic bit operations) may cause bytes following the field to by modified. Because the endianness of the bits within a field is the native endianness of the CPU[1], on big-endian machines, bit number zero is in the last byte of the field. Therefore, `set_bit(0, ptr)' on a 64-bit big-endian machine is roughly equivalent to `((char *)ptr)[7] |= 1', and since w1 driver uses a 32-bit field for holding the flags, this causes bytes beyond the field to be modified. [1] From Documentation/atomic_ops.txt: Native atomic bit operations are defined to operate on objects aligned to the size of an "unsigned long" C data type, and are least of that size. The endianness of the bits within each "unsigned long" are the native endianness of the cpu. Signed-off-by: Michal Nazarewicz Cc: Evgeniy Polyakov Cc: Greg KH Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed