Hi Wang, On 04/26/2019 12:56 PM, Wang YanQing wrote: > The current method to compare 64-bit numbers for conditional jump is: > > 1) Compare the high 32-bit first. > > 2) If the high 32-bit isn't the same, then goto step 4. > > 3) Compare the low 32-bit. > > 4) Check the desired condition. > > This method is right for unsigned comparison, but it is buggy for signed > comparison, because it does signed comparison for low 32-bit too. > > There is only one sign bit in 64-bit number, that is the MSB in the 64-bit > number, it is wrong to treat low 32-bit as signed number and do the signed > comparison for it. > > This patch fixes the bug. > > Signed-off-by: Wang YanQing <udknight@xxxxxxxxx> I presume this issue has coverage in our BPF kselftest suite, right? (If not, please also add a test into the test_verifier tool.) Thanks, Daniel
