My go code errors out with a strack trace like this:
unexpected fault address 0x0
fatal error: fault
[signal 0xb code=0x80 addr=0x0 pc=0x407d50]
goroutine 52246872 [running]:
runtime.throw(0xad6a77)
/usr/local/go/src/pkg/runtime/panic.c:464 +0x69 fp=0xc214d2c1f8
runtime.sigpanic()
/usr/local/go/src/pkg/runtime/os_linux.c:237 +0xe9 fp=0xc214d2c210
hash_lookup(0x671ec0, 0xc21001eed0, 0xc214d2c2d0)
/usr/local/go/src/pkg/runtime/hashmap.c:502 +0x150 fp=0xc214d2c290
runtime.mapaccess(0x671ec0, 0xc21001eed0, 0xc214d2c318, 0xc214d2c328, 0xc214d2c330)
/usr/local/go/src/pkg/runtime/hashmap.c:1004 +0x57 fp=0xc214d2c2c0
runtime.mapaccess2(0x671ec0, 0xc21001eed0, 0x389c, 0x2060009ae, 0xad4dc0, ...)
/usr/local/go/src/pkg/runtime/hashmap.c:1061 +0x5d fp=0xc214d2c308
growmobile.com/rtb/cache.HistogramCheck(0xc2121eafd0, 0xc, 0xeca93c6a0, 0x852a9f8, 0xad4dc0, ...)
/mnt/rtb_server/go/src/growmobile.com/rtb/cache/histogram_cache.go:211 +0x16b fp=0xc214d2c798
growmobile.com/rtb/controller.processBidRequest(0xc2121eafd0, 0xc, 0xeca93c6a0, 0x852a9f8, 0xad4dc0, ...)
/mnt/rtb_server/go/src/growmobile.com/rtb/controller/bidder_logic.go:272 +0x7c2 fp=0xc214d2e928
----- stack segment boundary -----
growmobile.com/rtb/controller.Bid(0x7f7a14250ed8, 0xc2197b3a00, 0xc2157f9dd0)
/mnt/rtb_server/go/src/growmobile.com/rtb/controller/controller.go:96 +0x903 fp=0x7f79f8dd9da0
net/http.HandlerFunc.ServeHTTP(0x800850, 0x7f7a14250ed8, 0xc2197b3a00, 0xc2157f9dd0)
/usr/local/go/src/pkg/net/http/server.go:1220 +0x40 fp=0x7f79f8dd9dc0
net/http.(*ServeMux).ServeHTTP(0xc21001e660, 0x7f7a14250ed8, 0xc2197b3a00, 0xc2157f9dd0)
/usr/local/go/src/pkg/net/http/server.go:1496 +0x163 fp=0x7f79f8dd9df8
net/http.serverHandler.ServeHTTP(0xc21001fa00, 0x7f7a14250ed8, 0xc2197b3a00, 0xc2157f9dd0)
/usr/local/go/src/pkg/net/http/server.go:1597 +0x16e fp=0x7f79f8dd9e38
net/http.(*conn).serve(0xc215d60a00)
/usr/local/go/src/pkg/net/http/server.go:1167 +0x7b7 fp=0x7f79f8dd9f98
runtime.goexit()
/usr/local/go/src/pkg/runtime/proc.c:1394 fp=0x7f79f8dd9fa0
created by net/http.(*Server).Serve
/usr/local/go/src/pkg/net/http/server.go:1644 +0x28b
goroutine 1 [chan receive]:
main.serve()
/mnt/rtb_server/go/src/growmobile.com/rtb/rtb_server/rtb_server.go:71 +0x5f0
main.main()
/mnt/rtb_server/go/src/growmobile.com/rtb/rtb_server/rtb_server.go:86 +0x1d8
At the time it is trying to access a hash which is a struct that maps to a pointer. The hash is a global one and looks like this:
var histogramCache = make(map[model.HistogramKey]*model.HistogramValue)
The access is a very standard access which looks like:
value, ok := histogramCache[key]
I tried to google something similar but could not find it. I do not use cgo or assertions. This is the go version we are using: go version go1.2 linux/amd64
Thank you, any help would be appreciated.
Maps are not safe for concurrent access. This might very well be the reason why your code is failing.
Use a central goroutine (see this example) and retrieve things using channels or use locking tools from sync.
Reinstalling the goland package fixed this problem for me. Some dependencies had been replaced by another package or were not correctly installed.