runtime: workbuf is (not) empty on RISC-V

[mknyszek]

#!watchflakes
post <- log ~ `workbuf is (not )?empty` && builder == "linux-riscv64-unmatched"

2023-07-31 18:05 linux-riscv64-unmatched go@789980ec (log)
2023-08-01 17:41 linux-riscv64-unmatched net@8ffa475f go@fb6f38dd x/net/internal/timeseries [build] (log)
2023-08-07 00:28 linux-riscv64-unmatched go@41981930 path/filepath [build] (log)
2023-08-08 21:20 linux-riscv64-unmatched go@fe1daf2e net/http_test [build] (log)
2023-08-16 17:51 linux-riscv64-unmatched go@91bea5a2 go/types.TestStdFixed (log)

CC @golang/riscv64

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
post <- log ~ `workbuf is (not )?empty` && builder == "linux-riscv64-unmatched"

2023-07-31 18:05 linux-riscv64-unmatched go@789980ec (log)

fatal error: workbuf is not empty

runtime stack:
runtime.throw({0x176436?, 0x2ee68?})
	runtime/panic.go:837 +0x44 fp=0x3ffff27490 sp=0x3ffff27468 pc=0x44d74
runtime.(*workbuf).checkempty(0x0?)
	runtime/mgcwork.go:344 +0x48 fp=0x3ffff274a8 sp=0x3ffff27490 pc=0x36340
runtime.getempty()
	runtime/mgcwork.go:357 +0x1f0 fp=0x3ffff27500 sp=0x3ffff274a8 pc=0x36538
runtime.handoff(0x3f8844a800)
	runtime/mgcwork.go:439 +0x2c fp=0x3ffff27528 sp=0x3ffff27500 pc=0x366fc
runtime.(*gcWork).balance(0x3f88025740)
	runtime/mgcwork.go:297 +0x50 fp=0x3ffff27538 sp=0x3ffff27528 pc=0x36220
runtime.gcDrain(0x3f88025740, 0x400000002?)
	runtime/mgcmark.go:1085 +0x154 fp=0x3ffff275a0 sp=0x3ffff27538 pc=0x2e6cc
runtime.gcBgMarkWorker.func2()
	runtime/mgc.go:1405 +0x84 fp=0x3ffff275e8 sp=0x3ffff275a0 pc=0x2abe4
runtime.systemstack()
	runtime/asm_riscv64.s:133 +0x54 fp=0x3ffff275f0 sp=0x3ffff275e8 pc=0x72ca4

2023-08-01 17:41 linux-riscv64-unmatched net@8ffa475f go@fb6f38dd x/net/internal/timeseries [build] (log)

fatal error: workbuf is empty
fatal error: workbuf is empty
fatal error: workbuf is empty

runtime stack:
runtime.throw({0x2fc22e?, 0x10eb0cad125ad?})
	runtime/panic.go:837 +0x44 fp=0x3f8004fed0 sp=0x3f8004fea8 pc=0x452b4
runtime.(*workbuf).checknonempty(0x364e4?)
	runtime/mgcwork.go:338 +0x48 fp=0x3f8004fee8 sp=0x3f8004fed0 pc=0x36558
runtime.trygetfull()
...
runtime.trygetfull()
	runtime/mgcwork.go:430 +0x74 fp=0x3f8004bf00 sp=0x3f8004bee8 pc=0x36914
runtime.(*gcWork).tryGet(0x3f8002e140)
	runtime/mgcwork.go:216 +0x68 fp=0x3f8004bf28 sp=0x3f8004bf00 pc=0x362f0
runtime.gcDrain(0x3f8002e140, 0x400000002?)
	runtime/mgcmark.go:1090 +0x1b4 fp=0x3f8004bf90 sp=0x3f8004bf28 pc=0x2e9a4
runtime.gcBgMarkWorker.func2()
	runtime/mgc.go:1405 +0x84 fp=0x3f8004bfd8 sp=0x3f8004bf90 pc=0x2aebc
runtime.systemstack()
	runtime/asm_riscv64.s:133 +0x54 fp=0x3f8004bfe0 sp=0x3f8004bfd8 pc=0x72ed4

2023-08-07 00:28 linux-riscv64-unmatched go@41981930 path/filepath [build] (log)

fatal error: workbuf is empty
fatal error: workbuf is empty
fatal error: workbuf is empty
fatal error: workbuf is empty

runtime stack:
runtime.throw({0x2fc5de?, 0x0?})
	runtime/panic.go:845 +0x44 fp=0x3f74093ed0 sp=0x3f74093ea8 pc=0x45384
runtime.(*workbuf).checknonempty(0x364e4?)
	runtime/mgcwork.go:338 +0x48 fp=0x3f74093ee8 sp=0x3f74093ed0 pc=0x36558
...
runtime.(*gcWork).tryGet(0x3f74023240)
	runtime/mgcwork.go:207 +0x34 fp=0x3fffa162d8 sp=0x3fffa162b0 pc=0x362bc
runtime.gcDrainN(0x3f74023240, 0x10000)
	runtime/mgcmark.go:1170 +0x118 fp=0x3fffa16300 sp=0x3fffa162d8 pc=0x2ed28
runtime.gcAssistAlloc1(0x3f740001a0, 0x3f743f21a0?)
	runtime/mgcmark.go:568 +0x144 fp=0x3fffa16360 sp=0x3fffa16300 pc=0x2d8c4
runtime.gcAssistAlloc.func1()
	runtime/mgcmark.go:476 +0x28 fp=0x3fffa16378 sp=0x3fffa16360 pc=0x2d760
runtime.systemstack()
	runtime/asm_riscv64.s:133 +0x54 fp=0x3fffa16380 sp=0x3fffa16378 pc=0x72fa4

2023-08-08 21:20 linux-riscv64-unmatched go@fe1daf2e net/http_test [build] (log)

fatal error: workbuf is empty
fatal error: workbuf is empty

runtime stack:
runtime.throw({0x2fc5be?, 0x0?})
	runtime/panic.go:859 +0x44 fp=0x3f80091ed0 sp=0x3f80091ea8 pc=0x453fc
runtime.(*workbuf).checknonempty(0x36504?)
	runtime/mgcwork.go:338 +0x48 fp=0x3f80091ee8 sp=0x3f80091ed0 pc=0x36578
runtime.trygetfull()
	runtime/mgcwork.go:430 +0x74 fp=0x3f80091f00 sp=0x3f80091ee8 pc=0x36934
...
runtime.(*gcWork).tryGet(0x3f80025740)
	runtime/mgcwork.go:207 +0x34 fp=0x3f80043f38 sp=0x3f80043f10 pc=0x362dc
runtime.gcDrainN(0x3f80025740, 0x10000)
	runtime/mgcmark.go:1170 +0x118 fp=0x3f80043f60 sp=0x3f80043f38 pc=0x2ed48
runtime.gcAssistAlloc1(0x3f800001a0, 0x3f803326b0?)
	runtime/mgcmark.go:568 +0x144 fp=0x3f80043fc0 sp=0x3f80043f60 pc=0x2d8c4
runtime.gcAssistAlloc.func1()
	runtime/mgcmark.go:476 +0x28 fp=0x3f80043fd8 sp=0x3f80043fc0 pc=0x2d760
runtime.systemstack()
	runtime/asm_riscv64.s:133 +0x54 fp=0x3f80043fe0 sp=0x3f80043fd8 pc=0x73174

2023-08-16 17:51 linux-riscv64-unmatched go@91bea5a2 go/types.TestStdFixed (log)

fatal error: workbuf is empty

runtime stack:
runtime.throw({0x2e8224?, 0x365d8?})
	/tmp/workdir-host-linux-riscv64-unmatched/go/src/runtime/panic.go:1018 +0x44 fp=0x3f8820ded0 sp=0x3f8820dea8 pc=0x47614
runtime.(*workbuf).checknonempty(0x36b6c?)
	/tmp/workdir-host-linux-riscv64-unmatched/go/src/runtime/mgcwork.go:338 +0x48 fp=0x3f8820dee8 sp=0x3f8820ded0 pc=0x36be0
runtime.trygetfull()
	/tmp/workdir-host-linux-riscv64-unmatched/go/src/runtime/mgcwork.go:430 +0x74 fp=0x3f8820df00 sp=0x3f8820dee8 pc=0x36f9c
runtime.(*gcWork).tryGet(0x3f88027c40)
...
	/tmp/workdir-host-linux-riscv64-unmatched/go/src/go/types/check.go:384 +0x1ec fp=0x3f8aa37a90 sp=0x3f8aa37a08 pc=0x17de9c
go/types.(*Checker).Files(...)
	/tmp/workdir-host-linux-riscv64-unmatched/go/src/go/types/check.go:344
go/types.(*Config).Check(0x3f888e1b60, {0x3f8970c050?, 0x45?}, 0x3f88fc6c00, {0x3f89bbfcf8, 0x1, 0x1}, 0x0)
	/tmp/workdir-host-linux-riscv64-unmatched/go/src/go/types/api.go:436 +0x18c fp=0x3f8aa37ae0 sp=0x3f8aa37a90 pc=0x16aba4
go/types_test.testTestDir(0x3f88ebeb60, {0x3f886eda80, 0x3b}, {0x3f883a0d98, 0x1d, 0xe3830?})
	/tmp/workdir-host-linux-riscv64-unmatched/go/src/go/types/stdlib_test.go:270 +0x544 fp=0x3f8aa37d30 sp=0x3f8aa37ae0 pc=0x25f33c
go/types_test.TestStdFixed(0x3f88ebeb60)
	/tmp/workdir-host-linux-riscv64-unmatched/go/src/go/types/stdlib_test.go:310 +0x140 fp=0x3f8aa37f78 sp=0x3f8aa37d30 pc=0x25f840
testing.tRunner(0x3f88ebeb60, 0x309dd8)

— watchflakes

[bcmills]

Duplicate of #62185