Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

cmd/pprof: nil pointer dereference when reading memory profiles #10364

mewmew opened this issue Apr 7, 2015 · 2 comments

cmd/pprof: nil pointer dereference when reading memory profiles #10364

mewmew opened this issue Apr 7, 2015 · 2 comments


Copy link

@mewmew mewmew commented Apr 7, 2015

go tool pprof works just fine with CPU profiles, but crashes for memory profiles with a nil pointer dereference.

$ go version
go version devel +0c8fe34 Tue Apr 7 17:48:03 2015 +0000 linux/amd64
$ go get
$ go test -run=NONE -bench=. -memprofile=lexer.mprof
$ go tool pprof lexer.test
Entering interactive mode (type "help" for commands)
(pprof) top5
1300ms of 2040ms total (63.73%)
Dropped 11 nodes (cum <= 10.20ms)
Showing top 5 nodes out of 36 (cum >= 840ms)
      flat  flat%   sum%        cum   cum%
     390ms 19.12% 19.12%      390ms 19.12%  runtime.indexbytebody
     360ms 17.65% 36.76%     1150ms 56.37%
     220ms 10.78% 47.55%      380ms 18.63%*lexer).next
     200ms  9.80% 57.35%      200ms  9.80%  runtime.memeqbody
     130ms  6.37% 63.73%      840ms 41.18%*lexer).accept
$ go tool pprof lexer.test lexer.mprof
panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xb code=0x1 addr=0x8 pc=0x486a1a]

goroutine 1 [running]:
regexp.(*bitState).reset(0x0, 0xc, 0x12, 0x0)
    /home/u/go/src/regexp/backtrack.go:70 +0x2a
regexp.(*machine).backtrack(0xc2080fcd80, 0x7f9b04fc2c38, 0xc2080fce58, 0x0, 0xc, 0x0, 0x2)
    /home/u/go/src/regexp/backtrack.go:314 +0x117
regexp.(*Regexp).doExecute(0xc2080f0aa0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xc2081f2320, 0xc, 0x0, 0x0, ...)
    /home/u/go/src/regexp/exec.go:449 +0x413
regexp.(*Regexp).MatchString(0xc2080f0aa0, 0xc2081f2320, 0xc, 0xc208263980)
    /home/u/go/src/regexp/regexp.go:400 +0x6e
cmd/pprof/internal/profile.(*Profile).Prune(0xc2080822a0, 0xc2080f0aa0, 0xc2080f0be0)
    /home/u/go/src/cmd/pprof/internal/profile/prune.go:30 +0x23a
cmd/pprof/internal/profile.(*Profile).RemoveUninteresting(0xc2080822a0, 0x0, 0x0)
    /home/u/go/src/cmd/pprof/internal/profile/prune.go:94 +0x479
cmd/pprof/internal/driver.PProf(0x7f9b04fc2790, 0xb87390, 0x9e25c8, 0x9e2bb8, 0x7f9b04fc2750, 0xc2080f6670, 0x7f9b04fc2708, 0xc208026150, 0x0, 0x0, ...)
    /home/u/go/src/cmd/pprof/internal/driver/driver.go:110 +0x998
    /home/u/go/src/cmd/pprof/pprof.go:28 +0x250

goroutine 17 [syscall, locked to thread]:
    /home/u/go/src/runtime/asm_amd64.s:1671 +0x1
@ianlancetaylor ianlancetaylor added this to the Go1.5 milestone Apr 7, 2015
Copy link

@dspezia dspezia commented Apr 27, 2015

I cannot reproduce with tip anymore.

Here is the recent history of the regexp package:

 +485f348 Michael Matloob 2015-04-17 17:10:07 +0000 regexp: set b.cap[0] and b.cap[1] only when captures requested
 +a513088 Matthew Brennan 2015-04-09 09:38:23 +0000 regexp: skip backtracker for long programs
 +fc9a234 Brad Fitzpatrick 2015-03-23 19:17:52 +0000 regexp: fix link to RE2 syntax
 +9323862 Michael Matloob 2015-03-23 16:17:42 +0000 regexp: port RE2's bitstate backtracker to the regexp package

It appears the OP demonstrated the issue between the introduction of the RE2's bitstate backtracker, and the corresponding later fixes.

I have checked that the problem can be reproduced by using version +0c8fe34 (the one used by the OP), and not anymore by using version +a513088 (the one including Matthew Brennan's fix).

So, I believe the problem is already fixed, and this issue can be closed.

Copy link

@bradfitz bradfitz commented Apr 27, 2015

@bradfitz bradfitz closed this Apr 27, 2015
@golang golang locked and limited conversation to collaborators Jun 25, 2016
Sign up for free to subscribe to this conversation on GitHub. Already have an account? Sign in.
None yet
Linked pull requests

Successfully merging a pull request may close this issue.

None yet
5 participants
You can’t perform that action at this time.