Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934508Ab3CUQor (ORCPT ); Thu, 21 Mar 2013 12:44:47 -0400 Received: from mail-pb0-f44.google.com ([209.85.160.44]:59634 "EHLO mail-pb0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934013Ab3CUQon (ORCPT ); Thu, 21 Mar 2013 12:44:43 -0400 From: Kent Overstreet To: linux-kernel@vger.kernel.org, linux-aio@kvack.org, akpm@linux-foundation.org Cc: Benjamin LaHaise , Kent Overstreet , Josh Boyer , Zach Brown Subject: [PATCH 33/33] aio: fix kioctx not being freed after cancellation at exit time Date: Thu, 21 Mar 2013 09:35:54 -0700 Message-Id: <1363883754-27966-34-git-send-email-koverstreet@google.com> X-Mailer: git-send-email 1.8.1.3 In-Reply-To: <1363883754-27966-1-git-send-email-koverstreet@google.com> References: <1363883754-27966-1-git-send-email-koverstreet@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2206 Lines: 64 From: Benjamin LaHaise The recent changes overhauling fs/aio.c introduced a bug that results in the kioctx not being freed when outstanding kiocbs are cancelled at exit_aio() time. Specifically, a kiocb that is cancelled has its completion events discarded by batch_complete_aio(), which then fails to wake up the process stuck in free_ioctx(). Fix this by removing the event suppression in batch_complete_aio() and modify the wait_event() condition in free_ioctx() appropriately. This patch was tested with the cancel operation in the thread based code posted yesterday. Signed-off-by: Benjamin LaHaise Cc: Kent Overstreet Cc: Josh Boyer Cc: Zach Brown Signed-off-by: Andrew Morton Signed-off-by: Kent Overstreet --- fs/aio.c | 15 +++------------ 1 file changed, 3 insertions(+), 12 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index 4dbd240..d2c1a82 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -349,7 +349,9 @@ static void free_ioctx(struct kioctx *ctx) kunmap_atomic(ring); while (atomic_read(&ctx->reqs_available) < ctx->nr_events - 1) { - wait_event(ctx->wait, head != ctx->shadow_tail); + wait_event(ctx->wait, + (head != ctx->shadow_tail) || + (atomic_read(&ctx->reqs_available) >= ctx->nr_events - 1)); avail = (head <= ctx->shadow_tail ? ctx->shadow_tail : ctx->nr_events) - head; @@ -774,17 +776,6 @@ void batch_complete_aio(struct batch_complete *batch) n = rb_parent(n); } - if (unlikely(xchg(&req->ki_cancel, - KIOCB_CANCELLED) == KIOCB_CANCELLED)) { - /* - * Can't use the percpu reqs_available here - could race - * with free_ioctx() - */ - atomic_inc(&req->ki_ctx->reqs_available); - aio_put_req(req); - continue; - } - if (unlikely(req->ki_eventfd != eventfd)) { if (eventfd) { /* Make event visible */ -- 1.8.1.3 -- 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/