Re: [GHC] #13945: 'ghc-pkg update' fails due to bad file descriptor error

#13945: 'ghc-pkg update' fails due to bad file descriptor error ---------------------------------+---------------------------------------- Reporter: mpickering | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.2.2 Component: Compiler | Version: 8.2.1-rc3 Resolution: | Keywords: Operating System: Linux | Architecture: Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | ---------------------------------+---------------------------------------- Comment (by bgamari): I am able to reproduce this locally. Here is a small reproducer, {{{#!c #include #include #include #include #include #include #include int main () { int fd = open("libraries/bootstrapping.conf/package.cache.lock", O_RDONLY|O_NOCTTY|O_NONBLOCK); int res; struct stat stat; res = fstat(fd, &stat); printf("stat: %s\n", strerror(errno)); res = flock(fd, LOCK_EX); printf("flock: %s\n", strerror(errno)); res = flock(fd, LOCK_UN); printf("funlock: %s\n", strerror(errno)); close(fd); return 0; } }}} When run in an NFS-mounted GHC tree with an existing lockfile this will fail with, {{{ $ gcc test.c && ./a.out stat: Success flock: Bad file descriptor funlock: Bad file descriptor }}} Strangely if one changes `O_RDONLY` to `O_RDWR` the failure becomes, {{{ $ gcc test.c && ./a.out stat: Success flock: No locks available funlock: No locks available }}} So I think this may be in part due to the read-only nature of the fd, but there may be more at play. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13945#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler