x/tools/gopls/internal/{util/lru,filecache}: SEGV in TestConcurrency [loong64 miscompile]

[gopherbot]

#!watchflakes
default <- ((pkg == "golang.org/x/tools/gopls/internal/util/lru" && test == "TestConcurrency") ||
 (pkg ==  "golang.org/x/tools/gopls/internal/filecache" && test == "TestConcurrency"))

Issue created automatically to collect these failures.

Example (log):

=== RUN   TestConcurrency
unexpected fault address 0x69abaf403f08
fatal error: fault
[signal SIGSEGV: segmentation violation code=0x2 addr=0x69abaf403f08 pc=0x1b3a58]

goroutine 168 gp=0x69abaeff3880 m=4 mp=0x69abaecef008 [running]:
runtime.throw({0x22a2bb?, 0x0?})
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/panic.go:1227 +0x38 fp=0x69abaf3fff08 sp=0x69abaf3ffee0 pc=0x8f628
runtime.sigpanic()
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/signal_unix.go:939 +0x240 fp=0x69abaf3fff60 sp=0x69abaf3fff08 pc=0x91210
...
created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 14
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 +0x98

goroutine 213 gp=0x69abaf01a8c0 m=nil [runnable]:
golang.org/x/sync/errgroup.(*Group).Go.func1()
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 fp=0x69abaf013fd8 sp=0x69abaf013fd8 pc=0x1b25f0
runtime.goexit({})
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/asm_loong64.s:701 +0x4 fp=0x69abaf013fd8 sp=0x69abaf013fd8 pc=0x973d4
created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 14
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 +0x98

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
default <- pkg == "golang.org/x/tools/gopls/internal/util/lru" && test == "TestConcurrency"

2025-09-19 01:07 x_tools-gotip-linux-loong64 tools@ef6334c8 go@b8af7443 x/tools/gopls/internal/util/lru.TestConcurrency [SKIP] (log)

=== RUN   TestConcurrency
unexpected fault address 0x69abaf403f08
fatal error: fault
[signal SIGSEGV: segmentation violation code=0x2 addr=0x69abaf403f08 pc=0x1b3a58]

goroutine 168 gp=0x69abaeff3880 m=4 mp=0x69abaecef008 [running]:
runtime.throw({0x22a2bb?, 0x0?})
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/panic.go:1227 +0x38 fp=0x69abaf3fff08 sp=0x69abaf3ffee0 pc=0x8f628
runtime.sigpanic()
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/signal_unix.go:939 +0x240 fp=0x69abaf3fff60 sp=0x69abaf3fff08 pc=0x91210
...
created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 14
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 +0x98

goroutine 213 gp=0x69abaf01a8c0 m=nil [runnable]:
golang.org/x/sync/errgroup.(*Group).Go.func1()
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 fp=0x69abaf013fd8 sp=0x69abaf013fd8 pc=0x1b25f0
runtime.goexit({})
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/asm_loong64.s:701 +0x4 fp=0x69abaf013fd8 sp=0x69abaf013fd8 pc=0x973d4
created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 14
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 +0x98

2025-09-19 21:25 x_tools-gotip-linux-loong64 tools@ef565f56 go@9693b94b x/tools/gopls/internal/util/lru.TestConcurrency [SKIP] (log)

=== RUN   TestConcurrency
unexpected fault address 0x2e0e58403f08
fatal error: fault
[signal SIGSEGV: segmentation violation code=0x2 addr=0x2e0e58403f08 pc=0x1b3a58]

goroutine 211 gp=0x2e0e57e79dc0 m=7 mp=0x2e0e58200008 [running]:
runtime.throw({0x22a2bb?, 0x0?})
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/panic.go:1227 +0x38 fp=0x2e0e583fff08 sp=0x2e0e583ffee0 pc=0x8f628
runtime.sigpanic()
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/signal_unix.go:939 +0x240 fp=0x2e0e583fff60 sp=0x2e0e583fff08 pc=0x91210
...
created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 24
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 +0x98

goroutine 238 gp=0x2e0e57e7ce00 m=nil [runnable]:
golang.org/x/sync/errgroup.(*Group).Go.func1()
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 fp=0x2e0e580997d8 sp=0x2e0e580997d8 pc=0x1b25f0
runtime.goexit({})
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/asm_loong64.s:701 +0x4 fp=0x2e0e580997d8 sp=0x2e0e580997d8 pc=0x973d4
created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 24
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 +0x98

2025-09-19 22:09 x_tools-gotip-linux-loong64 tools@cb57b4c2 go@177cd8d7 x/tools/gopls/internal/util/lru.TestConcurrency [SKIP] (log)

=== RUN   TestConcurrency
unexpected fault address 0x78efb403f08
fatal error: fault
[signal SIGSEGV: segmentation violation code=0x2 addr=0x78efb403f08 pc=0x1b3a58]

goroutine 44 gp=0x78efb0816c0 m=4 mp=0x78efb010008 [running]:
runtime.throw({0x22a2bb?, 0x0?})
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/panic.go:1227 +0x38 fp=0x78efb3fff08 sp=0x78efb3ffee0 pc=0x8f628
runtime.sigpanic()
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/signal_unix.go:939 +0x240 fp=0x78efb3fff60 sp=0x78efb3fff08 pc=0x91210
...
created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 42
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 +0x98

goroutine 138 gp=0x78efb2dfdc0 m=nil [runnable]:
golang.org/x/sync/errgroup.(*Group).Go.func1()
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 fp=0x78efb2ec7d8 sp=0x78efb2ec7d8 pc=0x1b25f0
runtime.goexit({})
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/asm_loong64.s:701 +0x4 fp=0x78efb2ec7d8 sp=0x78efb2ec7d8 pc=0x973d4
created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 42
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 +0x98

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
default <- pkg == "golang.org/x/tools/gopls/internal/util/lru" && test == "TestConcurrency"

2025-09-22 16:45 x_tools-gotip-linux-loong64 tools@4fb47d0d go@177cd8d7 x/tools/gopls/internal/util/lru.TestConcurrency [SKIP] (log)

=== RUN   TestConcurrency
unexpected fault address 0x114c10003f08
fatal error: fault
[signal SIGSEGV: segmentation violation code=0x1 addr=0x114c10003f08 pc=0x1b3a58]

goroutine 100 gp=0x114c0fbe7a40 m=4 mp=0x114c0f900008 [running]:
runtime.throw({0x22a2bb?, 0x0?})
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/panic.go:1227 +0x38 fp=0x114c0fffff08 sp=0x114c0ffffee0 pc=0x8f628
runtime.sigpanic()
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/signal_unix.go:939 +0x240 fp=0x114c0fffff60 sp=0x114c0fffff08 pc=0x91210
...
created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 26
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 +0x98

goroutine 225 gp=0x114c0fc37880 m=nil [runnable]:
golang.org/x/sync/errgroup.(*Group).Go.func1()
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 fp=0x114c0fc31fd8 sp=0x114c0fc31fd8 pc=0x1b25f0
runtime.goexit({})
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/asm_loong64.s:701 +0x4 fp=0x114c0fc31fd8 sp=0x114c0fc31fd8 pc=0x973d4
created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 26
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 +0x98

— watchflakes

[findleyr]

@golang/loong64

This is a pretty old test, so this seems to indicate a bug in the loong64 port.

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
default <- pkg == "golang.org/x/tools/gopls/internal/util/lru" && test == "TestConcurrency"

2025-09-22 16:45 x_tools-gotip-linux-loong64 tools@4fb47d0d go@22ac3288 x/tools/gopls/internal/util/lru.TestConcurrency [SKIP] (log)

=== RUN   TestConcurrency
unexpected fault address 0x67ad9e403f08
fatal error: fault
[signal SIGSEGV: segmentation violation code=0x2 addr=0x67ad9e403f08 pc=0x1b3a58]

goroutine 98 gp=0x67ad9da19340 m=8 mp=0x67ad9e100008 [running]:
runtime.throw({0x22a2bb?, 0x0?})
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/panic.go:1227 +0x38 fp=0x67ad9e3fff08 sp=0x67ad9e3ffee0 pc=0x8f628
runtime.sigpanic()
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/signal_unix.go:939 +0x240 fp=0x67ad9e3fff60 sp=0x67ad9e3fff08 pc=0x91210
...
created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 14
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 +0x98

goroutine 215 gp=0x67ad9da6a380 m=nil [runnable]:
golang.org/x/sync/errgroup.(*Group).Go.func1()
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 fp=0x67ad9da657d8 sp=0x67ad9da657d8 pc=0x1b25f0
runtime.goexit({})
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/asm_loong64.s:701 +0x4 fp=0x67ad9da657d8 sp=0x67ad9da657d8 pc=0x973d4
created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 14
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 +0x98

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
default <- pkg == "golang.org/x/tools/gopls/internal/util/lru" && test == "TestConcurrency"

2025-09-22 16:45 x_tools-gotip-linux-loong64 tools@4fb47d0d go@7e0251bf x/tools/gopls/internal/util/lru.TestConcurrency [SKIP] (log)

=== RUN   TestConcurrency
unexpected fault address 0x20627f003f08
fatal error: fault
[signal SIGSEGV: segmentation violation code=0x2 addr=0x20627f003f08 pc=0x1b3a68]

goroutine 46 gp=0x20627ec9ddc0 m=4 mp=0x20627ec00808 [running]:
runtime.throw({0x22a2bb?, 0x0?})
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/panic.go:1227 +0x38 fp=0x20627effff08 sp=0x20627efffee0 pc=0x8f638
runtime.sigpanic()
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/signal_unix.go:939 +0x240 fp=0x20627effff60 sp=0x20627effff08 pc=0x91220
...
created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 14
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 +0x98

goroutine 137 gp=0x20627ecdc000 m=nil [runnable]:
golang.org/x/sync/errgroup.(*Group).Go.func1()
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 fp=0x20627ece27d8 sp=0x20627ece27d8 pc=0x1b2600
runtime.goexit({})
	/home/swarming/.swarming/w/ir/x/w/goroot/src/runtime/asm_loong64.s:701 +0x4 fp=0x20627ece27d8 sp=0x20627ece27d8 pc=0x973e4
created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 14
	/home/swarming/.swarming/w/ir/x/w/gopath/pkg/mod/golang.org/x/sync@v0.17.0/errgroup/errgroup.go:78 +0x98

— watchflakes

[adonovan]

objdump gives me the following output. Possible assembler bug?

TEXT golang.org/x/tools/gopls/internal/util/lru_test.TestConcurrency.func1(SB) /Users/adonovan/x/tools/gopls/internal/util/lru/lru_test.go
  lru_test.go:103       0x1b3a30                28c042d4                MOVV 16(R22), R20                                                                                          
  lru_test.go:103       0x1b3a34                1400197e                LU12IW $203, R30                                                                                           
  lru_test.go:103       0x1b3a38                03bf83de                OR $4064, R30                                                                                              
  lru_test.go:103       0x1b3a3c                0012f878                SGTU R30, R3, R24                                                                                          
  lru_test.go:103       0x1b3a40                44033700                BNE R24, 205(PC)                                                                                           
  lru_test.go:103       0x1b3a44                15ffe69e                LU12IW $-204, R30                                                                                          
  lru_test.go:103       0x1b3a48                038083de                OR $32, R30                                                                                                
  lru_test.go:103       0x1b3a4c                0010f878                ADDV R30, R3, R24                                                                                          
  lru_test.go:103       0x1b3a50                0012e294                SGTU R24, R20                                                                                              
  lru_test.go:103       0x1b3a54                40031e80                BEQ R20, 199(PC)                                                                                           
  lru_test.go:103       0x1b3a58                273fa061                Unknown STPTR.D $-96, R3, R1    <--- SEGV                                                                      
...