From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5FBD92F24 for ; Wed, 12 Apr 2023 08:52:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD286C433EF; Wed, 12 Apr 2023 08:52:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1681289522; bh=eVeOYfFUZgYqjrBqTpVJacTwLpzHvUKZU36EBWEYO+s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XaXN8+ZuOJ8/dOmSwcp7229H+Dx2ozC4hoYGioDncvU576nm9yqyXQQgSF+jVX+Ti UURwX82nYo8ELLOCEj0sjSipRgHCC6ytGvp2llX9l9HXPoKX4K836amObdh0Qquj1/ iRBbkFTnqhY3aaPRI9DzOfdwyK5Hnplwmn+8fiXw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Wojciech Lukowicz , Jens Axboe , Sasha Levin Subject: [PATCH 6.2 132/173] io_uring: fix memory leak when removing provided buffers Date: Wed, 12 Apr 2023 10:34:18 +0200 Message-Id: <20230412082843.479732757@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230412082838.125271466@linuxfoundation.org> References: <20230412082838.125271466@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Wojciech Lukowicz [ Upstream commit b4a72c0589fdea6259720375426179888969d6a2 ] When removing provided buffers, io_buffer structs are not being disposed of, leading to a memory leak. They can't be freed individually, because they are allocated in page-sized groups. They need to be added to some free list instead, such as io_buffers_cache. All callers already hold the lock protecting it, apart from when destroying buffers, so had to extend the lock there. Fixes: cc3cec8367cb ("io_uring: speedup provided buffer handling") Signed-off-by: Wojciech Lukowicz Link: https://lore.kernel.org/r/20230401195039.404909-2-wlukowicz01@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- io_uring/io_uring.c | 2 +- io_uring/kbuf.c | 5 ++++- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index a4e9dbc7b67a8..add5cff7952c5 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -2722,8 +2722,8 @@ static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx) io_eventfd_unregister(ctx); io_alloc_cache_free(&ctx->apoll_cache, io_apoll_cache_free); io_alloc_cache_free(&ctx->netmsg_cache, io_netmsg_cache_free); - mutex_unlock(&ctx->uring_lock); io_destroy_buffers(ctx); + mutex_unlock(&ctx->uring_lock); if (ctx->sq_creds) put_cred(ctx->sq_creds); if (ctx->submitter_task) diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c index 0fdcc0adbdbcc..a90c820ce99e1 100644 --- a/io_uring/kbuf.c +++ b/io_uring/kbuf.c @@ -228,11 +228,14 @@ static int __io_remove_buffers(struct io_ring_ctx *ctx, return i; } + /* protects io_buffers_cache */ + lockdep_assert_held(&ctx->uring_lock); + while (!list_empty(&bl->buf_list)) { struct io_buffer *nxt; nxt = list_first_entry(&bl->buf_list, struct io_buffer, list); - list_del(&nxt->list); + list_move(&nxt->list, &ctx->io_buffers_cache); if (++i == nbufs) return i; cond_resched(); -- 2.39.2