#15260: Xmobar crashes with segmentation fault
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Reporter: Voronwe | Owner: (none)
Type: bug | Status: new
Priority: normal | Milestone: 8.6.1
Component: Compiler | Version: 8.5
Resolution: | Keywords:
Operating System: Linux | Architecture: x86_64 (amd64)
Type of failure: Runtime crash | Test Case:
Blocked By: | Blocking:
Related Tickets: | Differential Rev(s):
Wiki Page: |
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Comment (by osa1):
I wonder if this is a FFI misuse in X11 or xmobar. A `XNextEvent` FFI call
overrides an info table pointer:
{{{
Hardware watchpoint 2: ((StgClosure*)0x4200029f90)->header.info
Old value = (const StgInfoTable *) 0x0
New value = (const StgInfoTable *) 0xcfe1f0
bt #0 0x00007fdcd3143927 in XNextEvent () from /usr/lib/x86_64-linux- gnu/libX11.so.6 #1 0x000000000041385c in XUtil_zdwnextEventzq_info () #2 0x0000000000000011 in ?? () #3 0x0000000000000000 in ?? () }}}
(because this is reverse-execution new and old values are swapped, so old value is actually the new value being written by XNextEvent) Before overriding the info table ptr the object is the string `" "`: {{{
call printClosure(0x4200029f90) ghc-prim:GHC.Types.:(0xfa1501, 0xfa02e9) call printClosure(0xfa1501) ghc-prim:GHC.Types.C#(0x32#) call printClosure(0xfa02e9) ghc-prim:GHC.Types.[](0xcfdac8#) }}}
-- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15260#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler