runtime/pprof is failing with unhelpful "signal: blah" error messages on a lot of builders. For some reason we're not getting any further details though. E.g., which runtime/pprof test is failing or a sigpanic stack trace.

linux/386 ("signal: segmentation fault"):

http://build.golang.org/log/07ee563d20864714eacb0e7307b474f7442008d7
http://build.golang.org/log/9ec79d102626ec6e8fc3fd392380bc0b520f35f4

linux/amd64 ("signal: segmentation fault"):

http://build.golang.org/log/10ef18cb3cd066f886ae1e8a8402f506a3cdb119
http://build.golang.org/log/1f5252c1bfda6d36b3dd5f1145cb702e075244b6
http://build.golang.org/log/59217a106b0b2382b49fec6f3519ed8336a971a9
http://build.golang.org/log/7b6a1ea33b8328df1effa7c793cebe137db2bf92
http://build.golang.org/log/d9507dafead6918ad32bcfeb8755f1fa78556911
http://build.golang.org/log/f2c7f09283cbba3767f0494a7be2a33a0e53132a

linux/arm64 ("signal: segmentation fault (core dumped)"):

http://build.golang.org/log/581d4aa6c33932de2ed35c4be71f1cd351ac4525
http://build.golang.org/log/881f201ecb2c30677f09e7ea9c2f3c3c44dfbde7
http://build.golang.org/log/90143ce9b0f68fc8e7b62f5ca26404b13ab033e1
http://build.golang.org/log/e2606ffaac1b253d21cd788ce0a2c561edf4d61e
http://build.golang.org/log/f93c432aa050385a27afc0227df3b96c101fcf96

netbsd/386 ("signal: killed"):

http://build.golang.org/log/93432c69d4ebf598a862589ab9283eff5b66373a