On Thu, Mar 15, 2018 at 09:18:14PM -0600, Jason Gunthorpe wrote: > What is going on here is a bit subtle, in the kernel there is no > problem because the struct is copied using copy_from_user, so it > can safely have an 8 byte alignment, however in userspace it must > be constructed by concatenation with the ib_uverbs_alloc_pd_resp > struct. This is due to the required memory layout to execute the > command. > > Since ibv_uverbs_alloc_pd_resp is only 4 bytes long, this causes > misalignment, and the user space will experience an unexpected padding. > Currently it works around this via pointer maths. > > Make everything more robust by having the compiler reduce the alignment > of the struct to 4. The userspace has assertions to ensure this > works properly in all situations. > > Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx> > --- > include/uapi/rdma/bnxt_re-abi.h | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) Applied to for-next Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
