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Hem_D-PsKKEO_RF6pDy8_q2EcFX01NiS On Wed, Aug 28, 2024 at 04:11:29PM -0400, Eugene Loh wrote: > It's been a while, but if I remember correctly it's actually just the other > way around.  That is, to make stack and depth consistent, we're forced into > this "depth reduction" patch.  Put another way, the stack simply does not > include NULL pointers -- there is no way to remove them. > > E.g., let's say we have a buffer of 8 pointers and we ask for the stack and > get back: > >     0xdead 0xbeef 0xfeed 0xface NULL NULL NULL NULL > > Looks like 4 pointers.  But we don't count them.  We just use the return > value from the helper function.  If it tells us "4", then everything is > consistent.  But for some reason (I haven't looked at the code to figure out > why), it can be 5 or even 6.  So this patch bumps that value down -- to > attain the consistency I think you're asking about. So you are saying that the number of values that is actually filled in is not consistent with the return value of the bpf_get_stack() helper? That would sound like a kernel bug.