#172: bug in zlib binding makes cabal-install segfault ---------------------+------------------------------------------------------ Reporter: guest | Owner: duncan Type: defect | Status: closed Priority: normal | Milestone: Component: misc | Version: Severity: normal | Resolution: fixed Keywords: | Difficulty: hard (< 1 day) Ghcversion: 6.6 | Platform: Linux ---------------------+------------------------------------------------------ Changes (by duncan): * status: new => closed * resolution: => fixed Comment: I think I've found the bug. I think it was caused by a change between zlib-1.1.x and 1.2.x but it was also my fault for not being sufficiently careful with error handling. My guess is that in zlib-1.1.x, functions like inflateInit can return error codes without setting the string error message `msg`. The zlib binding code was always looking at the `msg` member of the `z_stream` structure and trying to read a string error message from it. If the `msg` member was NULL then this would produce the behavior in the ltrace output above. So I've changed the error handling code to check if the `msg` is NULL before inspecting its contents. This should fix the segfault but it does not explain why `inflateInit2` was returning `Z_STREAM_ERROR`. The documentation says it can return `Z_STREAM_ERROR` "if a parameter is invalid (such as a negative memLevel)" but I cannot see what it is talking about since `memLevel` is a parameter to `deflateInit` not `inflateInit`. I've uploaded zlib-0.4.0.3 http://hackage.haskell.org/cgi-bin/hackage-scripts/package/zlib-0.4.0.3 So I'm closing because I think the segfault is fixed. If you can still get a problem where decompressing the index file fails then re-open or file a new bug. -- Ticket URL: http://hackage.haskell.org/trac/hackage/ticket/172#comment:6 Hackage http://haskell.org/cabal/ Hackage: Cabal and related projects