[GHC] #3874: GHC.Exts.traceEvent segfaults

[GHC]

#3874: GHC.Exts.traceEvent segfaults
-------------------------------+--------------------------------------------
    Reporter:  cjs             |       Owner:                 
        Type:  bug             |      Status:  new            
    Priority:  normal          |   Component:  Runtime System 
     Version:  6.12.1          |    Keywords:  event, eventlog
          Os:  Linux           |    Testcase:                 
Architecture:  x86_64 (amd64)  |     Failure:  None/Unknown   
-------------------------------+--------------------------------------------

Comment(by cjs):

 Oh, and for further fun, I've walked through the calls from traceMessage
 down, and I don't see anywhere where we check for format specifiers in the
 string the user passes in. I think we want to change this function:
 {{{
 void postUserMsg(Capability *cap, char *msg)
 {
     postLogMsg(&capEventBuf[cap->no], EVENT_USER_MSG, msg, NULL);
 }
 }}}
 to have the body
 {{{
     postLogMsg(&capEventBuf[cap->no], EVENT_USER_MSG, "%s", msg, NULL);
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3874#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler