false staticcheck reports not reproducible with standalone staticcheck

[dvyukov]

Thank you for creating the issue!

• Yes, I'm using a binary release within 2 latest major releases. Only such installations are supported.
• Yes, I've searched similar issues on GitHub and didn't find any.
• Yes, I've included all information below (version, config, etc).

Please include the following information:

Version of golangci-lint

$ golangci-lint --version
golangci-lint has version v1.37.1 built from (unknown, mod sum: "h1:Unt38FmBltdoILo6oQUMp6PuxwWbJ1YyNSStCrvA7+8=") on (unknown)

Config file

$ cat .golangci.yml
# Copyright 2019 syzkaller project authors. All rights reserved.
# Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.

run:
  deadline: 8m
  skip-dirs:
    - pkg/kd
    - tools/syz-trace2syz
  # Autogenerated files take too much time and memory to load,
  # even if we skip them with skip-dirs.
  # So we define this tag and use it in the autogenerated files.
  build-tags:
    - codeanalysis

output:
  print-linter-name: false

linters:
  enable:
    - lll
    - vet
    - gofmt
    - golint
    - structcheck
    - unconvert
    - deadcode
    - goconst
    - unused
    - gosimple
    - varcheck
    - misspell
    - gocyclo
    - vetshadow
    - megacheck
    - stylecheck
    - govet
    - whitespace
    - nestif
    - goprintffuncname
    - godot
    - gocognit
    - funlen
    - dupl
    - staticcheck
    #- syz-linter
  disable:
    - bodyclose
    - depguard
    - dogsled
    - gochecknoglobals
    - gochecknoinits
    - godox
    - goimports
    - gomnd
    - gomodguard
    - gosec
    - maligned
    - rowserrcheck
    - testpackage
    - typecheck
    - ineffassign
    # errcheck would be good to enable, but we need to fix existing warnings first.
    - errcheck
    - interfacer
    - unparam
    - nakedret
    - prealloc
    - scopelint
    - gocritic
    - wsl

linters-settings:
  lll:
    line-length: 120
  gocyclo:
    # TODO: consider reducing this value.
    min-complexity: 24
  dupl:
    threshold: 60
  goconst:
    min-len: 3
    min-occurrences: 3
  nestif:
    # TODO: consider reducing this value.
    min-complexity: 12
  godot:
    check-all: true
  gocognit:
    # TODO: consider reducing this value.
    min-complexity: 70
  funlen:
    # TODO: consider reducing these value.
    lines: 140
    statements: 80
  custom:
    syz-linter:
      path: bin/syz-linter.so

issues:
  exclude-use-default: false
  max-same-issues: 0
  exclude:
    - "exported .* should have comment"
    - "comment on .* should be of the form"
    - "at least one file in a package should have a package comment"
    # This check gives false positives related to the standard log.Fatalf
    # (which is strange, standard log package should be supported).#
    #- "SA5011: possible nil pointer dereference"
  exclude-rules:
    - path: (pkg/csource/generated.go|pkg/build/linux_generated.go)
      linters:
        - lll
    - path: (sys/.*/init.*|sys/targets/common.go)
      text: "don't use ALL_CAPS in Go names|should not use ALL_CAPS in Go names"
    - path: (prog/.*)
      text: "methods on the same type should have the same receiver name"
    - path: (dashboard/app/.*_test\.go)
      linters:
        - dupl
    - path: (prog/.*_test\.go)
      linters:
        - goconst
    - path: (.*_test\.go)
      text: "Function '.*' is too long"

Go environment

$ go version && go env
go version go1.16 linux/amd64
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/.cache/go-build"
GOENV="/home/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/go1.16"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/go1.16/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.16"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/go/src/github.com/google/syzkaller/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build1111402449=/tmp/go-build -gno-record-gcc-switches"

Verbose output of running

$ golangci-lint cache clean
$ golangci-lint run -v
syzkaller$ golangci-lint cache clean

syzkaller$ golangci-lint run -v
INFO [config_reader] Config search paths: [./ /home/dvyukov/go/src/github.com/google/syzkaller /home/dvyukov/go/src/github.com/google /home/dvyukov/go/src/github.com /home/dvyukov/go/src /home/dvyukov/go /home/dvyukov /home /] 
INFO [config_reader] Used config file .golangci.yml 
INFO Loaded bin/syz-linter.so: syz-linter         
INFO [lintersdb] Active 22 linters: [deadcode dupl funlen gocognit goconst gocyclo godot gofmt golint goprintffuncname gosimple govet lll misspell nestif staticcheck structcheck stylecheck unconvert unused varcheck whitespace] 
INFO [loader] Using build tags: [codeanalysis]    
INFO [loader] Go packages loading at mode 575 (types_sizes|files|imports|name|compiled_files|deps|exports_file) took 2.757195184s 
INFO [runner/filename_unadjuster] Pre-built 0 adjustments in 44.045785ms 
INFO [linters context/goanalysis] analyzers took 1m32.020864178s with top 10 stages: buildir: 24.540296988s, dupl: 5.807368928s, gofmt: 3.943640542s, unconvert: 2.831761317s, inspect: 1.653510331s, golint: 1.378760885s, whitespace: 1.258429192s, the_only_name: 1.204208885s, ctrlflow: 1.100919231s, printf: 951.530516ms 
INFO [linters context/goanalysis] analyzers took 8.638602766s with top 10 stages: buildir: 6.583385026s, U1000: 2.05521774s 
INFO [runner/skip dirs] Skipped 23 issues from dir tools/syz-trace2syz/proggen by pattern tools/syz-trace2syz 
INFO [runner/skip dirs] Skipped 45 issues from dir pkg/kd by pattern pkg/kd 
INFO [runner/skip dirs] Skipped 17 issues from dir tools/syz-trace2syz/parser by pattern tools/syz-trace2syz 
INFO [runner] Issues before processing: 1622, after processing: 3 
INFO [runner] Processors filtering stat (out/in): sort_results: 3/3, exclude: 430/1480, nolint: 3/235, diff: 3/3, max_from_linter: 3/3, max_per_file_from_linter: 3/3, autogenerated_exclude: 1480/1537, exclude-rules: 235/430, max_same_issues: 3/3, source_code: 3/3, filename_unadjuster: 1622/1622, path_prettifier: 1622/1622, skip_files: 1622/1622, skip_dirs: 1537/1622, path_shortener: 3/3, severity-rules: 3/3, cgo: 1622/1622, identifier_marker: 1480/1480, uniq_by_line: 3/3, path_prefixer: 3/3 
INFO [runner] processing took 80.194485ms with stages: nolint: 32.84438ms, identifier_marker: 31.266005ms, path_prettifier: 5.38418ms, autogenerated_exclude: 4.074242ms, exclude: 3.980446ms, exclude-rules: 1.420827ms, skip_dirs: 984.961µs, cgo: 108.51µs, filename_unadjuster: 71.76µs, source_code: 49.752µs, uniq_by_line: 2.255µs, max_from_linter: 1.978µs, path_shortener: 1.957µs, max_same_issues: 1.264µs, max_per_file_from_linter: 690ns, diff: 327ns, sort_results: 302ns, severity-rules: 238ns, skip_files: 226ns, path_prefixer: 185ns 
INFO [runner] linters took 9.72484146s with stages: goanalysis_metalinter: 7.900493804s, unused: 1.744060286s 
sys/fuchsia/fidlgen/main.go:27:17: SA5011: possible nil pointer dereference
	arch := target.KernelHeaderArch
	               ^
tools/syz-runtest/runtest.go:271:6: SA5011: possible nil pointer dereference
	req.Output = a.Output
	    ^
tools/syz-runtest/runtest.go:272:6: SA5011: possible nil pointer dereference
	req.Info = a.Info
	    ^
INFO File cache stats: 369 entries of total size 3.3MiB 
INFO Memory: 126 samples, avg is 488.8MB, max is 812.6MB 
INFO Execution took 12.531268835s                 

Repro instructions:

$ git clone https://github.com/google/syzkaller.git
$ cd syzkaller
$ git checkout fcc6d71be2c3ce7d9305c04fc2e87af554571bac

Apply the following change:

diff --git a/.golangci.yml b/.golangci.yml
index cb0306b56650..3dcedd7390b8 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -42,7 +42,7 @@ linters:
     - funlen
     - dupl
     - staticcheck
-    - syz-linter
+    #- syz-linter
   disable:
     - bodyclose
     - depguard
@@ -105,7 +105,7 @@ issues:
     - "at least one file in a package should have a package comment"
     # This check gives false positives related to the standard log.Fatalf
     # (which is strange, standard log package should be supported).#
-    - "SA5011: possible nil pointer dereference"
+    #- "SA5011: possible nil pointer dereference"
   exclude-rules:
     - path: (pkg/csource/generated.go|pkg/build/linux_generated.go)
       linters:

Then:

$ go install github.com/golangci/golangci-lint/cmd/golangci-lint (vendored)
$ golangci-lint run ./tools/syz-runtest
tools/syz-runtest/runtest.go:271:6: SA5011: possible nil pointer dereference
	req.Output = a.Output
	    ^
tools/syz-runtest/runtest.go:272:6: SA5011: possible nil pointer dereference
	req.Info = a.Info

These are false reports, the line is preceded by log.Fatalf and standalone staticcheck does not produce these warnings:

$ go install honnef.co/go/tools/cmd/staticcheck@latest
$ staticcheck ./tools/syz-runtest

I've found #1189 but it seems to be only about reporting context/related info.

@dominikh

[ldez]

Duplicate of #1189

[dvyukov]

Duplicate of #1189

Isn't it only about reporting context/related info?

[ldez]

Maybe I misread.

I'm trying to reproduce.

[dvyukov]

One thing I forgot to mention:
The false warnings appeared only after switch to Go 1.16. Warnings did not show up with Go 1.15.
The same happened with golangci-lint 1.31. I've updated to 1.37 just to not report issues on older releases, but FWIW everything was exactly the same with 1.31.

[ldez]

Currently, I followed your steps, but I'm not able to run the linter on your project

$ golangci-lint run ./tools/syz-runtest
WARN [runner] Can't run linter goanalysis_metalinter: deadcode: analysis skipped: errors in package: [/home/ldez/sources/go/src/github.com/google/syzkaller/tools/syz-runtest/runtest.go:21:2: could not import github.com/google/syzkaller/pkg/instance (/home/ldez/sources/go/src/github.com/google/syzkaller/pkg/instance/instance.go:18:2: could not import github.com/google/syzkaller/pkg/build (/home/ldez/sources/go/src/github.com/google/syzkaller/pkg/build/build.go:17:2: could not import github.com/google/syzkaller/pkg/report (/home/ldez/sources/go/src/github.com/google/syzkaller/pkg/report/fuzz.go:9:2: could not import github.com/google/syzkaller/pkg/mgrconfig (/home/ldez/sources/go/src/github.com/google/syzkaller/pkg/mgrconfig/load.go:18:4: could not import github.com/google/syzkaller/sys (/home/ldez/sources/go/src/github.com/google/syzkaller/sys/sys.go:8:4: could not import github.com/google/syzkaller/sys/akaros/gen (sys/sys.go:8:2: cannot find package "." in:
	/home/ldez/sources/go/src/github.com/google/syzkaller/sys/akaros/gen)))))) /home/ldez/sources/go/src/github.com/google/syzkaller/tools/syz-runtest/runtest.go:22:2: could not import github.com/google/syzkaller/pkg/mgrconfig (/home/ldez/sources/go/src/github.com/google/syzkaller/pkg/mgrconfig/load.go:18:4: could not import github.com/google/syzkaller/sys (/home/ldez/sources/go/src/github.com/google/syzkaller/sys/sys.go:8:4: could not import github.com/google/syzkaller/sys/akaros/gen (sys/sys.go:8:2: cannot find package "." in:
	/home/ldez/sources/go/src/github.com/google/syzkaller/sys/akaros/gen))) /home/ldez/sources/go/src/github.com/google/syzkaller/tools/syz-runtest/runtest.go:24:2: could not import github.com/google/syzkaller/pkg/report (/home/ldez/sources/go/src/github.com/google/syzkaller/pkg/report/fuzz.go:9:2: could not import github.com/google/syzkaller/pkg/mgrconfig (/home/ldez/sources/go/src/github.com/google/syzkaller/pkg/mgrconfig/load.go:18:4: could not import github.com/google/syzkaller/sys (/home/ldez/sources/go/src/github.com/google/syzkaller/sys/sys.go:8:4: could not import github.com/google/syzkaller/sys/akaros/gen (sys/sys.go:8:2: cannot find package "." in:
	/home/ldez/sources/go/src/github.com/google/syzkaller/sys/akaros/gen)))) /home/ldez/sources/go/src/github.com/google/syzkaller/tools/syz-runtest/runtest.go:25:2: could not import github.com/google/syzkaller/pkg/rpctype (/home/ldez/sources/go/src/github.com/google/syzkaller/pkg/rpctype/rpctype.go:9:2: could not import github.com/google/syzkaller/pkg/host (/home/ldez/sources/go/src/github.com/google/syzkaller/pkg/host/features.go:10:2: could not import github.com/google/syzkaller/pkg/csource (/home/ldez/sources/go/src/github.com/google/syzkaller/pkg/csource/options.go:14:2: could not import github.com/google/syzkaller/pkg/mgrconfig (/home/ldez/sources/go/src/github.com/google/syzkaller/pkg/mgrconfig/load.go:18:4: could not import github.com/google/syzkaller/sys (/home/ldez/sources/go/src/github.com/google/syzkaller/sys/sys.go:8:4: could not import github.com/google/syzkaller/sys/akaros/gen (sys/sys.go:8:2: cannot find package "." in:
	/home/ldez/sources/go/src/github.com/google/syzkaller/sys/akaros/gen)))))) /home/ldez/sources/go/src/github.com/google/syzkaller/tools/syz-runtest/runtest.go:26:2: could not import github.com/google/syzkaller/pkg/runtest (/home/ldez/sources/go/src/github.com/google/syzkaller/pkg/runtest/run.go:27:2: could not import github.com/google/syzkaller/pkg/csource (/home/ldez/sources/go/src/github.com/google/syzkaller/pkg/csource/options.go:14:2: could not import github.com/google/syzkaller/pkg/mgrconfig (/home/ldez/sources/go/src/github.com/google/syzkaller/pkg/mgrconfig/load.go:18:4: could not import github.com/google/syzkaller/sys (/home/ldez/sources/go/src/github.com/google/syzkaller/sys/sys.go:8:4: could not import github.com/google/syzkaller/sys/akaros/gen (sys/sys.go:8:2: cannot find package "." in:
	/home/ldez/sources/go/src/github.com/google/syzkaller/sys/akaros/gen))))) /home/ldez/sources/go/src/github.com/google/syzkaller/tools/syz-runtest/runtest.go:28:4: could not import github.com/google/syzkaller/sys (/home/ldez/sources/go/src/github.com/google/syzkaller/sys/sys.go:8:4: could not import github.com/google/syzkaller/sys/akaros/gen (sys/sys.go:8:2: cannot find package "." in:
	/home/ldez/sources/go/src/github.com/google/syzkaller/sys/akaros/gen)) /home/ldez/sources/go/src/github.com/google/syzkaller/tools/syz-runtest/runtest.go:29:2: could not import github.com/google/syzkaller/vm (/home/ldez/sources/go/src/github.com/google/syzkaller/vm/vm.go:18:2: could not import github.com/google/syzkaller/pkg/mgrconfig (/home/ldez/sources/go/src/github.com/google/syzkaller/pkg/mgrconfig/load.go:18:4: could not import github.com/google/syzkaller/sys (/home/ldez/sources/go/src/github.com/google/syzkaller/sys/sys.go:8:4: could not import github.com/google/syzkaller/sys/akaros/gen (sys/sys.go:8:2: cannot find package "." in:
	/home/ldez/sources/go/src/github.com/google/syzkaller/sys/akaros/gen)))) /home/ldez/sources/go/src/github.com/google/syzkaller/tools/syz-runtest/runtest.go:15:2: "net" imported but not used] 
WARN [runner] Can't run linter unused: buildir: failed to load package : could not load export data: no export data for "github.com/google/syzkaller/sys/akaros/gen" 
ERRO Running error: buildir: failed to load package : could not load export data: no export data for "github.com/google/syzkaller/sys/akaros/gen" 

[dvyukov]

oh, sorry, please run make descriptions after check out

[ldez]

The problem will be fixed by the next version.

$ golangci-lint run ./tools/syz-runtest
tools/syz-runtest/runtest.go:271:6: SA5011: possible nil pointer dereference
	req.Output = a.Output
	    ^
tools/syz-runtest/runtest.go:272:6: SA5011: possible nil pointer dereference
	req.Info = a.Info
	    ^
$ ./golangci-lint run ./tools/syz-runtest

[ldez]

So it's not a duplicate 😉

For now, I don't know if it's related to the update of staticcheck #1756 or to something else

[ldez]

You tried to trick me 😄 :

$ go install honnef.co/go/tools/cmd/staticcheck@latest

But I also tried with v0.0.1-2020.1.6 and I have the same output as the latest

[ldez]

I confirm the problem has been fixed by #1756

[dvyukov]

You tried to trick me smile :

That was @dominikh who tried to trick both me and you :)
https://github.com/golangci/golangci-lint/pull/1756/files

So I need to wait for new golangci-lint version.
Trying to figure out if there is any workaround, e.g. manually import staticcheck 0.1.2