It is difficult to be certain, but I would put my bets on your sql anywhere driver may not be handling the c data lifetimes correctly, or might not be keeping a reference. It is difficult to tell without the driver code.
Thanks, -Daniel On Saturday, February 11, 2017 at 7:27:11 PM UTC-8, Mark Crook wrote: > > Hello, > > I'm seeing a panic in go version go1.8rc3 linux/amd64 while trying to > write a database driver using cgo. The go code runs in a docker container, > the database in another. > > Generally it works reliably, but occasionally, during repeated retrieval > of binary data (photos approx 100K to 2M), the code panics. > > I haven't isolated a reproducible example, but I think it's related to > this code: > > > value := new(C.a_sqlany_data_value) > > //load the column value binary data into value.buffer > > C.sqlany_get_column(r.stmt.ptr, C.sacapi_u32(i), value) > > > //copy the value buffer from C to Go > > val = C.GoBytes(unsafe.Pointer(value.buffer), C.int(value.length)) > > > I haven't seen the panic if the last line is commented out. > > Below is a stack trace. Perhaps it panics when a garbage collection is > triggered while waiting for C.GoBytes to return? > > Any suggestions? > > Thank you, > Mark > > > > runtime: unexpected return pc for runtime.sigpanic called from 0xc420e1a000 > fatal error: unknown caller pc > > runtime stack: > runtime.throw(0x59a90e, 0x11) > /go/src/runtime/panic.go:596 +0x95 > runtime.gentraceback(0xffffffffffffffff, 0xc42002a5d8, 0x0, 0xc4200c49c0, > 0x0, 0x0, 0x7fffffff, 0x7fb675ad5cb8, 0x0, 0x0, ...) > /go/src/runtime/traceback.go:317 +0x13ea > runtime.scanstack(0xc4200c49c0, 0xc420021828) > /go/src/runtime/mgcmark.go:842 +0x265 > runtime.newstack(0x0) > /go/src/runtime/stack.go:1064 +0x41e > runtime.morestack() > /go/src/runtime/asm_amd64.s:398 +0x86 > > goroutine 11 [GC worker (idle) (scan)]: > runtime.assertE2I2(0x56c220, 0x569e20, 0x841d20, 0xc42002a6b0, > 0xc4200c49e0, 0xc42002a640) > /go/src/runtime/iface.go:289 +0xb2 fp=0xc42002a5e0 sp=0xc42002a5d8 > runtime.preprintpanics(0xc42002a6b0) > /go/src/runtime/panic.go:389 +0x9f fp=0xc42002a650 sp=0xc42002a5e0 > panic(0x569e20, 0x841d20) > /go/src/runtime/panic.go:528 +0x1ab fp=0xc42002a6e8 sp=0xc42002a650 > runtime.panicmem() > /go/src/runtime/panic.go:63 +0x5e fp=0xc42002a708 sp=0xc42002a6e8 > runtime.sigpanic() > /go/src/runtime/signal_unix.go:290 +0x29f fp=0xc42002a758 sp=0xc42002a708 > created by runtime.gcBgMarkStartWorkers > /go/src/runtime/mgc.go:1410 +0x98 > > goroutine 1 [chan receive]: > testing.(*T).Run(0xc420072820, 0x598622, 0x8, 0x5a3718, 0xc420051d01) > /go/src/testing/testing.go:698 +0x2f4 > testing.runTests.func1(0xc420072820) > /go/src/testing/testing.go:881 +0x67 > testing.tRunner(0xc420072820, 0xc420051de0) > /go/src/testing/testing.go:657 +0x96 > testing.runTests(0xc42000cb60, 0x8461e0, 0x4, 0x4, 0xc420051ef8) > /go/src/testing/testing.go:887 +0x2c1 > testing.(*M).Run(0xc420051f20, 0xc420051f20) > /go/src/testing/testing.go:822 +0xfc > main.main() > github.com/mdcnz/sqlanywhere/_test/_testmain.go:48 +0xf7 > > goroutine 17 [syscall, 6 minutes, locked to thread]: > runtime.goexit() > /go/src/runtime/asm_amd64.s:2197 +0x1 > > goroutine 231 [GC assist wait]: > database/sql.convertAssign(0x5517a0, 0xc4200c20a0, 0x55a040, 0xc42000c0e0, > 0x85b5c0, 0x4535c0) > /go/src/database/sql/convert.go:161 +0x1a22 > database/sql.(*Rows).Scan(0xc42001c6c0, 0xc420041f68, 0x1, 0x1, 0x0, 0x0) > /go/src/database/sql/sql.go:2342 +0xca > github.com/mdcnz/sqlanywhere.TestBlob(0xc4200728f0) > /root/gome/src/github.com/mdcnz/sqlanywhere/test.go:26 +0x2a5 > testing.tRunner(0xc4200728f0, 0x5a3718) > /go/src/testing/testing.go:657 +0x96 > created by testing.(*T).Run > /go/src/testing/testing.go:697 +0x2ca > > goroutine 233 [chan receive]: > database/sql.(*Rows).awaitDone(0xc42001c6c0, 0x84b240, 0xc42047e080) > /go/src/database/sql/sql.go:2091 +0x54 > created by database/sql.(*Rows).initContextClose > /go/src/database/sql/sql.go:2086 +0x92 > > goroutine 232 [chan receive]: > database/sql.(*DB).connectionOpener(0xc42008c210) > /go/src/database/sql/sql.go:835 +0x4a > created by database/sql.Open > /go/src/database/sql/sql.go:580 +0x1c8 > exit status 2 > > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
