On Thu, May 2, 2019 at 6:02 PM XXX ZZZ <emartinez1...@gmail.com> wrote: > > No use of C via CGO at all. > > Afaik, there isn't any unsafe use of the string, we are basically reading it > from a get parameter (fasthttp server) on an http request and then adding it > into this structure, most of the times is just a 5 char string. Out of > several millions requests, this panic happens.
Does this "fasthttp" have any unsafe pointers? > > I failed to find any kind of race using go race detector, I'm currently doing > some more debugging, hopefuly I should have more info/tests soon. > > El jueves, 2 de mayo de 2019, 20:44:33 (UTC-3), Burak Serdar escribió: >> >> On Thu, May 2, 2019 at 3:56 PM Ian Lance Taylor <ia...@golang.org> wrote: >> > >> > On Thu, May 2, 2019 at 2:50 PM Anthony Martin <al...@pbrane.org> wrote: >> > > >> > > What version of Go are you using? >> > > >> > > XXX ZZZ <emarti...@gmail.com> once said: >> > > > fmt.(*pp).fmtString(0xc023c17740, 0x0, 0x5, 0xc000000076) >> > > > /usr/local/go/src/fmt/print.go:448 +0x132 >> > > > fmt.(*pp).printArg(0xc023c17740, 0x9978e0, 0xc016a68a30, 0x76) >> > > > /usr/local/go/src/fmt/print.go:684 +0x880 >> > > > fmt.(*pp).doPrintf(0xc023c17740, 0xa6e22f, 0x5, 0xc048c27818, 0x1, 0x1) >> > > > /usr/local/go/src/fmt/print.go:1112 +0x3ff >> > > > fmt.Sprintf(0xa6e22f, 0x5, 0xc048c27818, 0x1, 0x1, 0x80, 0xa36200) >> > > > /usr/local/go/src/fmt/print.go:214 +0x66 >> > > >> > > This shows signs of memory corruption. The last argument passed to >> > > fmtString (0xc000000076) should be the same as the last argument >> > > passed to printArg (0x76 or 'v') but it has some high bits set. Also, >> > > the pointer to the format string data changes from 0xa6e22f (which is >> > > probably in the .rodata section of the binary) to 0x0. >> > > >> > > Something is amiss. >> > >> > The change from 0x76 to 0xc000000076 does not necessarily indicate a >> > problem. The stack backtrace does not know the types. The value here >> > is a rune, which is 32 bits. The compiler will only set the low order >> > 32 bits on the stack, leaving the high order 32 bits unset. So the >> > 0xc000000000 could just be garbage left on the stack. >> > >> > I don't *think* the format string is changing. I think the 0 is from >> > the string being printed, not the format string. They both happen to >> > be length 5. >> >> There's something that doesn't make sense here. The 0 is from the >> string being printed, it is not the format string. But how can that >> be? >> >> Even if there is a race, the string cannot have a 0 for the slice, can >> it? So the other option is when Sprintf is called, the string being >> printed is already corrupt. Can there be an overflow somewhere that is >> somehow undetected? Any unsafe use in the program? >> >> >> > >> > Ian >> > >> > -- >> > 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 golan...@googlegroups.com. >> > For more options, visit https://groups.google.com/d/optout. > > -- > 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 golang-nuts+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. -- 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 golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
