From patchwork Mon Aug 21 14:22:54 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Schwab X-Patchwork-Id: 22261 Received: (qmail 83179 invoked by alias); 21 Aug 2017 14:23:10 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 83164 invoked by uid 89); 21 Aug 2017 14:23:08 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-24.1 required=5.0 tests=BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, RP_MATCHES_RCVD, SPF_PASS, UNWANTED_LANGUAGE_BODY autolearn=ham version=3.3.2 spammy=9616, 6916, Hx-languages-length:3728 X-HELO: mx1.suse.de From: Andreas Schwab To: Florian Weimer Cc: libc-alpha@sourceware.org, Carlos O'Donell Subject: [PATCH] Always do locking when iterating over list of streams (bug 15142) References: <20170817133507.CEA5341DB79B0@oldenburg.str.redhat.com> <07ffdd4d-3bef-6371-2790-de3979ce22a1@redhat.com> X-Yow: Will it improve my CASH FLOW? Date: Mon, 21 Aug 2017 16:22:54 +0200 In-Reply-To: (Andreas Schwab's message of "Mon, 21 Aug 2017 11:39:54 +0200") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux) MIME-Version: 1.0 [BZ #15142] * libio/genops.c (_IO_list_all_stamp): Delete. All uses removed. (_IO_flush_all_lockp): Always lock list_all_lock. (_IO_flush_all_linebuffered): Likewise. (_IO_unbuffer_all): Likewise. diff --git a/libio/genops.c b/libio/genops.c index 6ad7346cae..89376d1b9b 100644 --- a/libio/genops.c +++ b/libio/genops.c @@ -38,10 +38,6 @@ static _IO_lock_t list_all_lock = _IO_lock_initializer; #endif -/* Used to signal modifications to the list of FILE decriptors. */ -static int _IO_list_all_stamp; - - static _IO_FILE *run_fp; #ifdef _IO_MTSAFE_IO @@ -69,16 +65,12 @@ _IO_un_link (struct _IO_FILE_plus *fp) if (_IO_list_all == NULL) ; else if (fp == _IO_list_all) - { - _IO_list_all = (struct _IO_FILE_plus *) _IO_list_all->file._chain; - ++_IO_list_all_stamp; - } + _IO_list_all = (struct _IO_FILE_plus *) _IO_list_all->file._chain; else for (f = &_IO_list_all->file._chain; *f; f = &(*f)->_chain) if (*f == (_IO_FILE *) fp) { *f = fp->file._chain; - ++_IO_list_all_stamp; break; } fp->file._flags &= ~_IO_LINKED; @@ -106,7 +98,6 @@ _IO_link_in (struct _IO_FILE_plus *fp) #endif fp->file._chain = (_IO_FILE *) _IO_list_all; _IO_list_all = fp; - ++_IO_list_all_stamp; #ifdef _IO_MTSAFE_IO _IO_funlockfile ((_IO_FILE *) fp); run_fp = NULL; @@ -794,17 +785,13 @@ _IO_flush_all_lockp (int do_lock) { int result = 0; struct _IO_FILE *fp; - int last_stamp; #ifdef _IO_MTSAFE_IO - __libc_cleanup_region_start (do_lock, flush_cleanup, NULL); - if (do_lock) - _IO_lock_lock (list_all_lock); + _IO_cleanup_region_start_noarg (flush_cleanup); + _IO_lock_lock (list_all_lock); #endif - last_stamp = _IO_list_all_stamp; - fp = (_IO_FILE *) _IO_list_all; - while (fp != NULL) + for (fp = (_IO_FILE *) _IO_list_all; fp != NULL; fp = fp->_chain) { run_fp = fp; if (do_lock) @@ -823,21 +810,11 @@ _IO_flush_all_lockp (int do_lock) if (do_lock) _IO_funlockfile (fp); run_fp = NULL; - - if (last_stamp != _IO_list_all_stamp) - { - /* Something was added to the list. Start all over again. */ - fp = (_IO_FILE *) _IO_list_all; - last_stamp = _IO_list_all_stamp; - } - else - fp = fp->_chain; } #ifdef _IO_MTSAFE_IO - if (do_lock) - _IO_lock_unlock (list_all_lock); - __libc_cleanup_region_end (0); + _IO_lock_unlock (list_all_lock); + _IO_cleanup_region_end (0); #endif return result; @@ -856,16 +833,13 @@ void _IO_flush_all_linebuffered (void) { struct _IO_FILE *fp; - int last_stamp; #ifdef _IO_MTSAFE_IO _IO_cleanup_region_start_noarg (flush_cleanup); _IO_lock_lock (list_all_lock); #endif - last_stamp = _IO_list_all_stamp; - fp = (_IO_FILE *) _IO_list_all; - while (fp != NULL) + for (fp = (_IO_FILE *) _IO_list_all; fp != NULL; fp = fp->_chain) { run_fp = fp; _IO_flockfile (fp); @@ -875,15 +849,6 @@ _IO_flush_all_linebuffered (void) _IO_funlockfile (fp); run_fp = NULL; - - if (last_stamp != _IO_list_all_stamp) - { - /* Something was added to the list. Start all over again. */ - fp = (_IO_FILE *) _IO_list_all; - last_stamp = _IO_list_all_stamp; - } - else - fp = fp->_chain; } #ifdef _IO_MTSAFE_IO @@ -919,6 +884,12 @@ static void _IO_unbuffer_all (void) { struct _IO_FILE *fp; + +#ifdef _IO_MTSAFE_IO + _IO_cleanup_region_start_noarg (flush_cleanup); + _IO_lock_lock (list_all_lock); +#endif + for (fp = (_IO_FILE *) _IO_list_all; fp; fp = fp->_chain) { if (! (fp->_flags & _IO_UNBUFFERED) @@ -961,6 +932,11 @@ _IO_unbuffer_all (void) used. */ fp->_mode = -1; } + +#ifdef _IO_MTSAFE_IO + _IO_lock_unlock (list_all_lock); + _IO_cleanup_region_end (0); +#endif }