Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932951Ab1CYX6T (ORCPT ); Fri, 25 Mar 2011 19:58:19 -0400 Received: from kroah.org ([198.145.64.141]:48856 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932457Ab1CYX6I (ORCPT ); Fri, 25 Mar 2011 19:58:08 -0400 X-Mailbox-Line: From gregkh@clark.kroah.org Fri Mar 25 16:56:36 2011 Message-Id: <20110325235636.570549856@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Fri, 25 Mar 2011 16:55:38 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Roland Dreier Subject: [01/23] aio: wake all waiters when destroying ctx References: <20110325235537.660072281@clark.kroah.org> Content-Disposition: inline; filename=aio-wake-all-waiters-when-destroying-ctx.patch In-Reply-To: <20110325235654.GA24416@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2160 Lines: 84 From: Roland Dreier commit e91f90bb0bb10be9cc8efd09a3cf4ecffcad0db1 upstream. The test program below will hang because io_getevents() uses add_wait_queue_exclusive(), which means the wake_up() in io_destroy() only wakes up one of the threads. Fix this by using wake_up_all() in the aio code paths where we want to make sure no one gets stuck. // t.c -- compile with gcc -lpthread -laio t.c #include #include #include #include static const int nthr = 2; void *getev(void *ctx) { struct io_event ev; io_getevents(ctx, 1, 1, &ev, NULL); printf("io_getevents returned\n"); return NULL; } int main(int argc, char *argv[]) { io_context_t ctx = 0; pthread_t thread[nthr]; int i; io_setup(1024, &ctx); for (i = 0; i < nthr; ++i) pthread_create(&thread[i], NULL, getev, ctx); sleep(1); io_destroy(ctx); for (i = 0; i < nthr; ++i) pthread_join(thread[i], NULL); return 0; } Signed-off-by: Roland Dreier Reviewed-by: Jeff Moyer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/aio.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/fs/aio.c +++ b/fs/aio.c @@ -497,7 +497,7 @@ static inline void really_put_req(struct ctx->reqs_active--; if (unlikely(!ctx->reqs_active && ctx->dead)) - wake_up(&ctx->wait); + wake_up_all(&ctx->wait); } static void aio_fput_routine(struct work_struct *data) @@ -1219,7 +1219,7 @@ static void io_destroy(struct kioctx *io * by other CPUs at this point. Right now, we rely on the * locking done by the above calls to ensure this consistency. */ - wake_up(&ioctx->wait); + wake_up_all(&ioctx->wait); put_ioctx(ioctx); /* once for the lookup */ } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/