On 2012/6/12 6:05, Pawel Jakub Dawidek wrote:
Author: pjd Date: Mon Jun 11 22:05:26 2012 New Revision: 236935 URL: http://svn.freebsd.org/changeset/base/236935Log: fdgrowtable() no longer drops the filedesc lock so it is enough to retry finding free file descriptor only once after fdgrowtable(). Spotted by: pluknet MFC after: 1 month Modified: head/sys/kern/kern_descrip.c Modified: head/sys/kern/kern_descrip.c ============================================================================== --- head/sys/kern/kern_descrip.c Mon Jun 11 21:56:37 2012 (r236934) +++ head/sys/kern/kern_descrip.c Mon Jun 11 22:05:26 2012 (r236935) @@ -1478,29 +1478,33 @@ fdalloc(struct thread *td, int minfd, in /* * Search the bitmap for a free descriptor. If none is found, try * to grow the file table. Keep at it until we either get a file - * descriptor or run into process or system limits; fdgrowtable() - * may drop the filedesc lock, so we're in a race. + * descriptor or run into process or system limits. */ - for (;;) { - fd = fd_first_free(fdp, minfd, fdp->fd_nfiles); - if (fd>= maxfd) - return (EMFILE); - if (fd< fdp->fd_nfiles) - break; + fd = fd_first_free(fdp, minfd, fdp->fd_nfiles); + if (fd>= maxfd) + return (EMFILE); + if (fd>= fdp->fd_nfiles) { #ifdef RACCT PROC_LOCK(p); - error = racct_set(p, RACCT_NOFILE, min(fdp->fd_nfiles * 2, maxfd)); + error = racct_set(p, RACCT_NOFILE, + min(fdp->fd_nfiles * 2, maxfd)); PROC_UNLOCK(p); if (error != 0) return (EMFILE); #endif fdgrowtable(fdp, min(fdp->fd_nfiles * 2, maxfd)); + /* Retry... */ + fd = fd_first_free(fdp, minfd, fdp->fd_nfiles); + if (fd>= maxfd) + return (EMFILE); } /* * Perform some sanity checks, then mark the file descriptor as * used and return it to the caller. */ + KASSERT((unsigned int)fd< min(maxfd, fdp->fd_nfiles), + ("invalid descriptor %d", fd)); KASSERT(!fdisused(fdp, fd), ("fd_first_free() returned non-free descriptor")); KASSERT(fdp->fd_ofiles[fd] == NULL, ("file descriptor isn't free"));
My machine crashed with this change. http://people.freebsd.org/~davidxu/fdcrash.jpg Regards, _______________________________________________ svn-src-head@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
