On Mon, Jun 22, 2020 at 05:09:04PM -0700, Andrii Nakryiko wrote: > Extend original variable-length tests with a case to catch a common > existing pattern of testing for < 0 for errors. Note because > verifier also tracks upper bounds and we know it can not be greater > than MAX_LEN here we can skip upper bound check. > > In ALU64 enabled compilation converting from long->int return types > in probe helpers results in extra instruction pattern, <<= 32, s >>= 32. > The trade-off is the non-ALU64 case works. If you really care about > every extra insn (XDP case?) then you probably should be using original > int type. > > In addition adding a sext insn to bpf might help the verifier in the > general case to avoid these types of tricks. > > Signed-off-by: John Fastabend <john.fastabend@xxxxxxxxx> Please keep John's 'Author:' on the patch. git commit --author= --amend or keep 'From:' when you applied to your local git. Also add your SOB after John's. Even if you didn't change the patch at all. Same thing if you've reworked the patch.
