#4993: getDirectoryContents goes into an infinite loop
-----------------------+----------------------------------------------------
Reporter: bos | Owner:
Type: bug | Status: new
Priority: normal | Component: libraries/directory
Version: 7.0.1 | Keywords:
Testcase: | Blockedby:
Os: Linux | Blocking:
Architecture: x86 | Failure: Runtime crash
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This is a really peculiar bug. Prepare for some fun!
I'm using a tool called boxgrinder to create a virtual machine image for
running in Amazon's EC2 compute environment. The virtual machine is
intended to contain GHC and a few libraries. I'm running boxgrinder itself
in an EC2 virtual machine.
boxgrinder works fine on a 64-bit virtual machine, when creating a 64-bit
virtual machine, but gets stuck forever when I try to run it in a 32-bit
VM to create a 32-bit image.
The reason for boxgrinder hanging is that when installing {{{GHC}}},
{{{ghc-pkg}}} is going into an infinite loop. I've got a super simple
reproduction:
{{{
import System.Directory
main = getDirectoryContents "." >>= print
}}}
If compiled, the above command runs fine in the regular 32-bit system
image, but not in the {{{chroot}}} filesystem created by boxgrinder. In
there, it goes into an infinite loop right after reading some of the
directory contents:
{{{
... everything looks normal ...
open(".", O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_DIRECTORY|O_CLOEXEC) = 3
getdents64(3, /* 25 entries */, 32768) = 640
getdents64(3, /* 0 entries */, 32768) = 0
--- SIGVTALRM (Virtual timer expired) @ 0 (0) ---
sigreturn() = ? (mask now [])
--- SIGVTALRM (Virtual timer expired) @ 0 (0) ---
sigreturn() = ? (mask now [])
--- SIGVTALRM (Virtual timer expired) @ 0 (0) ---
sigreturn() = ? (mask now [])
... and no more life! ...
}}}
I have verified that this infinite loop occurs both with 6.12.3 and 7.0.2
RC2. Investigating further at the moment.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4993>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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