hwpmc: fix false callchain assertion on the PMC_UR ring

[afscoelho_gmail.com]

Summary

pmc_capture_user_callchain() asserts that TDP_CALLCHAIN is set on the
current thread, but PMC_UR samples never set that flag -- only PMC_HR
and PMC_SR do. That makes the assertion always fail for PMC_UR,
panicking INVARIANTS kernels as soon as pmcstat -U is used.

Skip the assertion for PMC_UR. No functional change on kernels built
without INVARIANTS.

Signed-off-by: Andre Silva <[e-mail]>
Sponsored by: AMD

[ali_mashtizadeh.com]

These two diffs should be merged but does it fix the -U flag bug? I don’t see why we need to keep the two path I had a patch to unify them but I hit a different assert.

[afscoelho_gmail.com]

In D58572#1344314, @ali_mashtizadeh.com wrote:

These two diffs should be merged but does it fix the -U flag bug? I don’t see why we need to keep the two path I had a patch to unify them but I hit a different assert.

Yes, we can merge, no problem. I just kept them separate because I thought the two assertion bugs were clearer as two small diffs. D58572 fixes the -U panic, while D58571 fixes the other runcount assertion. With both applied, -U survived my stress test.