From e8bb9129d185bf98ba173ec018bf2b6c9d62aa6c Mon Sep 17 00:00:00 2001 From: Nick Ripley Date: Fri, 1 Nov 2024 13:43:34 -0400 Subject: [PATCH] runtime/pprof: relax TestProfilerStackDepth MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The TestProfilerStackDepth/heap test can spuriously fail if the profiler happens to capture a stack with an allocation several frames deep into runtime code. The pprof API hides runtime frames at the leaf-end of stacks, but those frames still count against the profiler's stack depth limit. The test checks only the first stack it finds with the desired prefix and fails if it's not deep enough or doesn't have the right root frame. So it can fail in that scenario, even though the implementation isn't really broken. Relax the test to check that there is at least one stack with desired prefix, depth, and root frame. Fixes #70112 Change-Id: I337fb3cccd1ddde76530b03aa1ec0f9608aa4112 Reviewed-on: https://go-review.googlesource.com/c/go/+/623998 Reviewed-by: Felix Geisendörfer Reviewed-by: Michael Pratt Reviewed-by: Cherry Mui LUCI-TryBot-Result: Go LUCI --- src/runtime/pprof/pprof_test.go | 35 +++++++++++++++++++++++---------- 1 file changed, 25 insertions(+), 10 deletions(-) diff --git a/src/runtime/pprof/pprof_test.go b/src/runtime/pprof/pprof_test.go index 19641f62aa..64ca9957d2 100644 --- a/src/runtime/pprof/pprof_test.go +++ b/src/runtime/pprof/pprof_test.go @@ -2545,19 +2545,34 @@ func TestProfilerStackDepth(t *testing.T) { t.Logf("Profile = %v", p) stks := profileStacks(p) - var stk []string - for _, s := range stks { - if hasPrefix(s, test.prefix) { - stk = s - break + var matchedStacks [][]string + for _, stk := range stks { + if !hasPrefix(stk, test.prefix) { + continue } + // We may get multiple stacks which contain the prefix we want, but + // which might not have enough frames, e.g. if the profiler hides + // some leaf frames that would count against the stack depth limit. + // Check for at least one match + matchedStacks = append(matchedStacks, stk) + if len(stk) != depth { + continue + } + if rootFn, wantFn := stk[depth-1], "runtime/pprof.produceProfileEvents"; rootFn != wantFn { + continue + } + // Found what we wanted + return } - if len(stk) != depth { - t.Fatalf("want stack depth = %d, got %d", depth, len(stk)) - } + for _, stk := range matchedStacks { + t.Logf("matched stack=%s", stk) + if len(stk) != depth { + t.Errorf("want stack depth = %d, got %d", depth, len(stk)) + } - if rootFn, wantFn := stk[depth-1], "runtime/pprof.produceProfileEvents"; rootFn != wantFn { - t.Fatalf("want stack stack root %s, got %v", wantFn, rootFn) + if rootFn, wantFn := stk[depth-1], "runtime/pprof.produceProfileEvents"; rootFn != wantFn { + t.Errorf("want stack stack root %s, got %v", wantFn, rootFn) + } } }) }