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| author | Cherry Zhang <cherryyz@google.com> | 2019-10-31 10:32:31 -0400 |
|---|---|---|
| committer | Cherry Zhang <cherryyz@google.com> | 2019-11-05 18:58:41 +0000 |
| commit | f07cbc7f88e5e15e41ec8b9c2b850d2179e0834e (patch) | |
| tree | e49406289dc2b3e6f9f8cf3733d3f287f2f462da /src/runtime/signal_unix.go | |
| parent | fb05264fe1626c9d0b6d00d51e6c4d8d213d6dc7 (diff) | |
| download | go-f07cbc7f88e5e15e41ec8b9c2b850d2179e0834e.tar.gz go-f07cbc7f88e5e15e41ec8b9c2b850d2179e0834e.zip | |
runtime: don't fetch G from signal stack when using cgo
When using cgo, we save G to TLS, and when a signal happens, we
load G from TLS in sigtramp. This should give us a valid G. Don't
try to fetch from the signal stack. In particular, C code may
change the signal stack or call our signal handler directly (e.g.
TSAN), so we are not necessarily running on the original gsignal
stack where we saved G.
Also skip saving G on the signal stack when using cgo.
Updates #35249.
Change-Id: I40749ce6682709bd4ebfdfd9f23bd0f317fc197d
Reviewed-on: https://go-review.googlesource.com/c/go/+/204519
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Diffstat (limited to 'src/runtime/signal_unix.go')
| -rw-r--r-- | src/runtime/signal_unix.go | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/src/runtime/signal_unix.go b/src/runtime/signal_unix.go index 6563186392..fab8574d1c 100644 --- a/src/runtime/signal_unix.go +++ b/src/runtime/signal_unix.go @@ -360,9 +360,11 @@ func preemptM(mp *m) { func sigFetchG(c *sigctxt) *g { switch GOARCH { case "arm", "arm64": - if inVDSOPage(c.sigpc()) { - // Before making a VDSO call we save the g to the bottom of the - // signal stack. Fetch from there. + if !iscgo && inVDSOPage(c.sigpc()) { + // When using cgo, we save the g on TLS and load it from there + // in sigtramp. Just use that. + // Otherwise, before making a VDSO call we save the g to the + // bottom of the signal stack. Fetch from there. // TODO: in efence mode, stack is sysAlloc'd, so this wouldn't // work. sp := getcallersp() |