On Thu, Oct 30, 2025 at 10:48:03PM +0100, Jiri Olsa wrote: > On Wed, Oct 29, 2025 at 08:17:05AM +0100, Jiri Olsa wrote: > > On Tue, Oct 28, 2025 at 08:39:33PM -0700, Josh Poimboeuf wrote: > > > On Mon, Oct 27, 2025 at 11:38:50PM +0100, Jiri Olsa wrote: > > > > On Mon, Oct 27, 2025 at 01:19:52PM -0700, Josh Poimboeuf wrote: > > > > > On Mon, Oct 27, 2025 at 01:52:18PM +0000, [email protected] wrote: > > > > > > Does this revert re-introduce the BPF selftest failure that was > > > > > > fixed in > > > > > > 2019? The test > > > > > > tools/testing/selftests/bpf/prog_tests/stacktrace_map_raw_tp.c > > > > > > still exists in the kernel tree. > > > > > > > > > > I have the same question. And note there may be subtle differences > > > > > between the frame pointer and ORC unwinders. The testcase would need > > > > > to > > > > > pass for both. > > > > > > > > as I wrote in the other email that test does not check ips directly, > > > > it just compare stacks taken from bpf_get_stackid and bpf_get_stack > > > > helpers.. so it passes for both orc and frame pointer unwinder > > > > > > Ok. So the original fix wasn't actually a fix at all? It would be good > > > to understand that and mention it in the commit log. Otherwise it's not > > > clear why it's ok to revert a fix with no real explanation. > > > > I think it was a fix when it was pushed 6 years ago, but some > > unwind change along that time made it redundant, I'll try to > > find what the change was > > hum I can't tell what changed since v5.2 (kernel version when [1] landed) > that reverted the behaviour which the [1] commit was fixing > > I did the test for both orc and framepointer unwind with and without the > fix (revert of [1]) and except for the initial entry it does not seem to > change the rest of the unwind ... though I'd expect orc unwind to have > more entries > > please check results below > > any idea? thanks, > jirka
The "missing" ORC entries are probably fine, they're likely caused by the compiler generating more tail calls with FP disabled. -- Josh
