runtime: SIGBUS in go/types in TestVet

[gopherbot]

#!watchflakes
default <- pkg == "cmd/vet" && test == "TestVet/method"

Issue created automatically to collect these failures.

Example (log):

=== RUN   TestVet/method
=== PAUSE TestVet/method
=== CONT  TestVet/method
    vet_test.go:195: error check failed: 
        Unmatched Errors:
        unexpected fault address 0x10769e80
        fatal error: fault
        [signal SIGBUS: bus error code=0x2 addr=0x10769e80 pc=0x10769e80]
        goroutine 1 gp=0xc000002380 m=2 mp=0xc00004c808 [running]:
        runtime.throw({0x10663d90?, 0x28?})
...
        	../../runtime/proc.go:435 +0xce fp=0xc000043f38 sp=0xc000043f18 pc=0x1038d26e
        runtime.gcBgMarkWorker(0xc0000ca620)
        	../../runtime/mgc.go:1423 +0xe9 fp=0xc000043fc8 sp=0xc000043f38 pc=0x10339389
        runtime.gcBgMarkStartWorkers.gowrap1()
        	../../runtime/mgc.go:1339 +0x25 fp=0xc000043fe0 sp=0xc000043fc8 pc=0x10339265
        runtime.goexit({})
        	../../runtime/asm_amd64.s:1700 +0x1 fp=0xc000043fe8 sp=0xc000043fe0 pc=0x10394601
        created by runtime.gcBgMarkStartWorkers in goroutine 1
        	../../runtime/mgc.go:1339 +0x105
--- FAIL: TestVet/method (4.09s)

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
default <- pkg == "cmd/vet" && test == "TestVet/method"

2025-01-22 16:03 gotip-darwin-amd64_14 go@70b603f4 cmd/vet.TestVet/method (log)

=== RUN   TestVet/method
=== PAUSE TestVet/method
=== CONT  TestVet/method
    vet_test.go:195: error check failed: 
        Unmatched Errors:
        unexpected fault address 0x10769e80
        fatal error: fault
        [signal SIGBUS: bus error code=0x2 addr=0x10769e80 pc=0x10769e80]
        goroutine 1 gp=0xc000002380 m=2 mp=0xc00004c808 [running]:
        runtime.throw({0x10663d90?, 0x28?})
...
        	../../runtime/proc.go:435 +0xce fp=0xc000043f38 sp=0xc000043f18 pc=0x1038d26e
        runtime.gcBgMarkWorker(0xc0000ca620)
        	../../runtime/mgc.go:1423 +0xe9 fp=0xc000043fc8 sp=0xc000043f38 pc=0x10339389
        runtime.gcBgMarkStartWorkers.gowrap1()
        	../../runtime/mgc.go:1339 +0x25 fp=0xc000043fe0 sp=0xc000043fc8 pc=0x10339265
        runtime.goexit({})
        	../../runtime/asm_amd64.s:1700 +0x1 fp=0xc000043fe8 sp=0xc000043fe0 pc=0x10394601
        created by runtime.gcBgMarkStartWorkers in goroutine 1
        	../../runtime/mgc.go:1339 +0x105
--- FAIL: TestVet/method (4.09s)

— watchflakes

[adonovan]

The SIGBUS occurs on this line:

		panic(fmt.Sprintf("%s: unknown expression type %T", check.fset.Position(e.Pos()), e))

The addresses are properly aligned. I can't correlate the program counter to a valid instruction in the disassembly of this amd64 executable though.

[adonovan]

The second stack implicates a different line:

				d.pred.add(n)

Either way, this is a sign of memory corruption or a code generation bug.

[mknyszek]

This might be an issue with this particular Darwin machine, we've seen other bugs filed by watchflakes that look like it's an issue with some of our fleet. This might be similar.

[mknyszek]

This is actually exactly the same machine we saw earlier! #71300