From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753321AbcAESEz (ORCPT ); Tue, 5 Jan 2016 13:04:55 -0500 Received: from mx2.suse.de ([195.135.220.15]:50399 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752628AbcAERrk (ORCPT ); Tue, 5 Jan 2016 12:47:40 -0500 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jiri Slaby Subject: [PATCH 3.12 38/91] usblp: do not set TASK_INTERRUPTIBLE before lock Date: Tue, 5 Jan 2016 18:46:22 +0100 Message-Id: X-Mailer: git-send-email 2.6.4 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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: Jiri Slaby Signed-off-by: Jiri Slaby --- drivers/usb/class/usblp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/class/usblp.c b/drivers/usb/class/usblp.c index d4c47d5d7625..7ac5fac8600b 100644 --- a/drivers/usb/class/usblp.c +++ b/drivers/usb/class/usblp.c @@ -870,11 +870,11 @@ static int usblp_wwait(struct usblp *usblp, int nonblock) 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) -- 2.6.4