Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758254AbZDWMtX (ORCPT ); Thu, 23 Apr 2009 08:49:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757022AbZDWMtA (ORCPT ); Thu, 23 Apr 2009 08:49:00 -0400 Received: from mga11.intel.com ([192.55.52.93]:4353 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757113AbZDWMs5 convert rfc822-to-8bit (ORCPT ); Thu, 23 Apr 2009 08:48:57 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.40,235,1239001200"; d="scan'208";a="684264646" From: "Sosnowski, Maciej" To: KOSAKI Motohiro CC: Nick Piggin , LKML , Linus Torvalds , Andrew Morton , Andrea Arcangeli , Jeff Moyer , "linux-mm@kvack.org" , "linux-fsdevel@vger.kernel.org" , "David S. Miller" , "Leech, Christopher" , "netdev@vger.kernel.org" Date: Thu, 23 Apr 2009 13:48:50 +0100 Subject: RE: [RFC][PATCH v3 6/6] fix wrong get_user_pages usage in iovlock.c Thread-Topic: [RFC][PATCH v3 6/6] fix wrong get_user_pages usage in iovlock.c Thread-Index: AcnA66MnMpg/MOUhRuG1P38wELQzYQDJY/jA Message-ID: <129600E5E5FB004392DDC3FB599660D79A253143@irsmsx504.ger.corp.intel.com> References: <20090415174658.AC4F.A69D9226@jp.fujitsu.com> <129600E5E5FB004392DDC3FB599660D792A39DCE@irsmsx504.ger.corp.intel.com> <20090419202447.FFC2.A69D9226@jp.fujitsu.com> In-Reply-To: <20090419202447.FFC2.A69D9226@jp.fujitsu.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4165 Lines: 117 KOSAKI Motohiro wrote: >> KOSAKI Motohiro wrote: >>>>> I would perhaps not fold gup_fast conversions into the same patch as >>>>> the fix. >>>> >>>> OK. I'll fix. >>> >>> Done. >>> >>> >>> >>> =================================== >>> Subject: [Untested][RFC][PATCH] fix wrong get_user_pages usage in iovlock.c >>> >>> down_read(mmap_sem) >>> get_user_pages() >>> up_read(mmap_sem) >>> >>> is fork unsafe. >>> fix it. >>> >>> Signed-off-by: KOSAKI Motohiro >>> Cc: Maciej Sosnowski >>> Cc: David S. Miller >>> Cc: Chris Leech >>> Cc: netdev@vger.kernel.org >>> --- >>> drivers/dma/iovlock.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> Index: b/drivers/dma/iovlock.c >>> =================================================================== >>> --- a/drivers/dma/iovlock.c 2009-04-13 22:58:36.000000000 +0900 >>> +++ b/drivers/dma/iovlock.c 2009-04-14 20:27:16.000000000 +0900 >>> @@ -104,8 +104,6 @@ struct dma_pinned_list *dma_pin_iovec_pa 0, /* force */ >>> page_list->pages, >>> NULL); >>> - up_read(¤t->mm->mmap_sem); >>> - >>> if (ret != page_list->nr_pages) >>> goto unpin; >>> >>> @@ -127,6 +125,8 @@ void dma_unpin_iovec_pages(struct dma_pi if (!pinned_list) >>> return; >>> >>> + up_read(¤t->mm->mmap_sem); >>> + >>> for (i = 0; i < pinned_list->nr_iovecs; i++) { >>> struct dma_page_list *page_list = &pinned_list->page_list[i]; >>> for (j = 0; j < page_list->nr_pages; j++) { >> >> I have tried it with net_dma and here is what I've got. > > Thanks. > Instead, How about this? > Unfortuantelly still does not look good. Regards, Maciej ============================================= [ INFO: possible recursive locking detected ] 2.6.30-rc2 #14 --------------------------------------------- iperf/9932 is trying to acquire lock: (&mm->mmap_sem){++++++}, at: [] do_page_fault+0x170/0 but task is already holding lock: (&mm->mmap_sem){++++++}, at: [] tcp_recvmsg+0x3a/0xa7 other info that might help us debug this: 2 locks held by iperf/9932: #0: (&mm->mmap_sem){++++++}, at: [] tcp_recvmsg+0x3a #1: (sk_lock-AF_INET){+.+.+.}, at: [] sk_wait_data+0 stack backtrace: Pid: 9932, comm: iperf Tainted: G W 2.6.30-rc2 #14 Call Trace: [] ? validate_chain+0x55a/0xc7c [] ? __lock_acquire+0x763/0x7ec [] ? lock_acquire+0xc6/0xea [] ? do_page_fault+0x170/0x29d [] ? down_read+0x46/0x77 [] ? do_page_fault+0x170/0x29d [] ? do_page_fault+0x170/0x29d [] ? page_fault+0x1f/0x30 [] ? copy_user_generic_string+0x2d/0x40 [] ? memcpy_toiovec+0x36/0x66 [] ? skb_copy_datagram_iovec+0x133/0x1f0 [] ? tcp_rcv_established+0x297/0x71a [] ? tcp_v4_do_rcv+0x2c/0x1d5 [] ? autoremove_wake_function+0x0/0x2e [] ? tcp_prequeue_process+0x6b/0x7e [] ? tcp_recvmsg+0x449/0xa70 [] ? __lock_acquire+0x781/0x7ec [] ? sock_common_recvmsg+0x30/0x45 [] ? sock_recvmsg+0xf0/0x10f [] ? trace_hardirqs_on_caller+0x11d/0x148 [] ? autoremove_wake_function+0x0/0x2e [] ? restore_args+0x0/0x30 [] ? fget_light+0xd5/0xdf [] ? fget_light+0x49/0xdf [] ? sys_recvfrom+0xbc/0x119 [] ? try_to_wake_up+0x2ae/0x2c0 [] ? audit_syscall_entry+0x192/0x1bd [] ? system_call_fastpath+0x16/0x1b -- 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/