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| author | Heschi Kreinick <heschi@google.com> | 2018-08-17 16:32:02 -0400 |
|---|---|---|
| committer | Heschi Kreinick <heschi@google.com> | 2018-08-23 19:48:12 +0000 |
| commit | c9986d1452f3ef226bfd044fb0f128175a7dff03 (patch) | |
| tree | b8f78037be8e0d16aec2700255bfdd52a5e3c0b6 /src/runtime/traceback.go | |
| parent | b15a1e3cfb64aeeb90f74e0748524b38fde5ebf9 (diff) | |
| download | go-c9986d1452f3ef226bfd044fb0f128175a7dff03.tar.gz go-c9986d1452f3ef226bfd044fb0f128175a7dff03.zip | |
runtime: fix use of wrong g in gentraceback
gentraceback gets the currently running g to do some sanity checks, but
should use gp everywhere to do its actual work. Some noncritical checks
later accidentally used g instead of gp. This seems like it could be a
problem in many different contexts, but I noticed in Windows profiling,
where profilem calls gentraceback on a goroutine from a different
thread.
Change-Id: I3da27a43e833b257f6411ee6893bdece45a9323f
Reviewed-on: https://go-review.googlesource.com/128895
Run-TryBot: Heschi Kreinick <heschi@google.com>
Reviewed-by: Austin Clements <austin@google.com>
Diffstat (limited to 'src/runtime/traceback.go')
| -rw-r--r-- | src/runtime/traceback.go | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/src/runtime/traceback.go b/src/runtime/traceback.go index a1f32016b9e..78589f5ea38 100644 --- a/src/runtime/traceback.go +++ b/src/runtime/traceback.go @@ -99,8 +99,9 @@ func gentraceback(pc0, sp0, lr0 uintptr, gp *g, skip int, pcbuf *uintptr, max in if skip > 0 && callback != nil { throw("gentraceback callback cannot be used with non-zero skip") } - g := getg() - if g == gp && g == g.m.curg { + + // Don't call this "g"; it's too easy get "g" and "gp" confused. + if ourg := getg(); ourg == gp && ourg == ourg.m.curg { // The starting sp has been passed in as a uintptr, and the caller may // have other uintptr-typed stack references as well. // If during one of the calls that got us here or during one of the @@ -200,7 +201,7 @@ func gentraceback(pc0, sp0, lr0 uintptr, gp *g, skip int, pcbuf *uintptr, max in // g0, this systemstack is at the top of the stack. // if we're not on g0 or there's a no curg, then this is a regular call. sp := frame.sp - if flags&_TraceJumpStack != 0 && f.funcID == funcID_systemstack && gp == g.m.g0 && gp.m.curg != nil { + if flags&_TraceJumpStack != 0 && f.funcID == funcID_systemstack && gp == gp.m.g0 && gp.m.curg != nil { sp = gp.m.curg.sched.sp frame.sp = sp cgoCtxt = gp.m.curg.cgoCtxt @@ -425,7 +426,7 @@ func gentraceback(pc0, sp0, lr0 uintptr, gp *g, skip int, pcbuf *uintptr, max in if frame.pc > f.entry { print(" +", hex(frame.pc-f.entry)) } - if g.m.throwing > 0 && gp == g.m.curg || level >= 2 { + if gp.m != nil && gp.m.throwing > 0 && gp == gp.m.curg || level >= 2 { print(" fp=", hex(frame.fp), " sp=", hex(frame.sp), " pc=", hex(frame.pc)) } print("\n") |