Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933739AbbLGPNe (ORCPT ); Mon, 7 Dec 2015 10:13:34 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:32906 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965245AbbLGPHF (ORCPT ); Mon, 7 Dec 2015 10:07:05 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jiri Slaby , Pete Zaitcev Subject: [PATCH 4.3 108/125] usblp: do not set TASK_INTERRUPTIBLE before lock Date: Mon, 7 Dec 2015 10:02:01 -0500 Message-Id: <20151207145757.539171727@linuxfoundation.org> X-Mailer: git-send-email 2.6.3 In-Reply-To: <20151207145752.225938417@linuxfoundation.org> References: <20151207145752.225938417@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2569 Lines: 67 4.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiri Slaby commit 19cd80a214821f4b558560ebd76bfb2c38b4f3d8 upstream. It is not permitted to set task state before lock. usblp_wwait sets the state to TASK_INTERRUPTIBLE and calls mutex_lock_interruptible. Upon return from that function, the state will be TASK_RUNNING again. This is clearly a bug and a warning is generated with LOCKDEP too: WARNING: CPU: 1 PID: 5109 at kernel/sched/core.c:7404 __might_sleep+0x7d/0x90() do not call blocking ops when !TASK_RUNNING; state=1 set at [] usblp_wwait+0xa0/0x310 [usblp] Modules linked in: ... CPU: 1 PID: 5109 Comm: captmon Tainted: G W 4.2.5-0.gef2823b-default #1 Hardware name: LENOVO 23252SG/23252SG, BIOS G2ET33WW (1.13 ) 07/24/2012 ffffffff81a4edce ffff880236ec7ba8 ffffffff81716651 0000000000000000 ffff880236ec7bf8 ffff880236ec7be8 ffffffff8106e146 0000000000000282 ffffffff81a50119 000000000000028b 0000000000000000 ffff8802dab7c508 Call Trace: ... [] warn_slowpath_fmt+0x46/0x50 [] __might_sleep+0x7d/0x90 [] mutex_lock_interruptible_nested+0x2f/0x4b0 [] usblp_wwait+0xcc/0x310 [usblp] [] usblp_write+0x72/0x350 [usblp] [] __vfs_write+0x28/0xf0 ... Commit 7f477358e2384c54b190cc3b6ce28277050a041b (usblp: Implement the ENOSPC convention) moved the set prior locking. So move it back after the lock. Signed-off-by: Jiri Slaby Fixes: 7f477358e2 ("usblp: Implement the ENOSPC convention") Acked-By: Pete Zaitcev Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/usblp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/usb/class/usblp.c +++ b/drivers/usb/class/usblp.c @@ -884,11 +884,11 @@ static int usblp_wwait(struct usblp *usb add_wait_queue(&usblp->wwait, &waita); for (;;) { - set_current_state(TASK_INTERRUPTIBLE); if (mutex_lock_interruptible(&usblp->mut)) { rc = -EINTR; break; } + set_current_state(TASK_INTERRUPTIBLE); rc = usblp_wtest(usblp, nonblock); mutex_unlock(&usblp->mut); if (rc <= 0) -- 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/