31.08.2017 13:38, Dmitry V. Levin пишет: > On Thu, Aug 31, 2017 at 02:11:34PM +0400, Stanislav Kinsburskiy wrote: >> Due to integer variables alignment size of struct autofs_v5_packet in 300 >> bytes in 32-bit architectures (instead of 304 bytes in 64-bits >> architectures). >> >> This may lead to memory corruption (64 bits kernel always send 304 bytes, >> while 32-bit userspace application expects for 300). >> >> https://jira.sw.ru/browse/PSBM-71078 >> >> Signed-off-by: Stanislav Kinsburskiy <skinsbur...@virtuozzo.com> >> --- >> include/uapi/linux/auto_fs4.h | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/include/uapi/linux/auto_fs4.h b/include/uapi/linux/auto_fs4.h >> index e02982f..8729a47 100644 >> --- a/include/uapi/linux/auto_fs4.h >> +++ b/include/uapi/linux/auto_fs4.h >> @@ -137,6 +137,8 @@ struct autofs_v5_packet { >> __u32 pid; >> __u32 tgid; >> __u32 len; >> + __u32 blob; /* This is needed to align structure up to 8 >> + bytes for ALL archs including 32-bit */ >> char name[NAME_MAX+1]; >> }; > > This change breaks ABI because it changes offsetof(struct autofs_v5_packet, > name). > If you need to fix the alignment, use __attribute__((aligned(8))). >
Nice to know you're watching. Yes, attribute is better. But how ABI is broken? On x86_64 this alignment is implied, so nothing is changed. > An alignment change would also be an ABI breakage on 32-bit architectures, > though. > True. But from my POW better have it working on 64bit archs for 32bit apps. But anyway, upstream guys will device, whether they want 32-bit autofs applications properly work on 64 or 32 bits. _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel
