From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f193.google.com ([209.85.192.193]:36001 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751298AbeDFRBp (ORCPT ); Fri, 6 Apr 2018 13:01:45 -0400 Received: by mail-pf0-f193.google.com with SMTP id g14so1176005pfh.3 for ; Fri, 06 Apr 2018 10:01:45 -0700 (PDT) Date: Fri, 6 Apr 2018 10:01:42 -0700 From: Omar Sandoval To: linux-block@vger.kernel.org Cc: Jens Axboe , kernel-team@fb.com, Tetsuo Handa , Dmitry Vyukov Subject: Re: [PATCH] loop: fix LOOP_GET_STATUS lock imbalance Message-ID: <20180406170142.GB11697@vader> References: <6bee3eddc24ef5525ca12efb023e66b2503cb178.1523033157.git.osandov@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <6bee3eddc24ef5525ca12efb023e66b2503cb178.1523033157.git.osandov@fb.com> Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org On Fri, Apr 06, 2018 at 09:57:03AM -0700, Omar Sandoval wrote: > From: Omar Sandoval > > Commit 2d1d4c1e591f made loop_get_status() drop lo_ctx_mutex before > returning, but the loop_get_status_old(), loop_get_status64(), and > loop_get_status_compat() wrappers don't call loop_get_status() if the > passed argument is NULL. The callers expect that the lock is dropped, so > make sure we drop it in that case, too. > > Reported-by: syzbot+31e8daa8b3fc129e75f2@syzkaller.appspotmail.com > Fixes: 2d1d4c1e591f ("loop: don't call into filesystem while holding lo_ctl_mutex") > Signed-off-by: Omar Sandoval > --- > Based on Linus' tree. > > drivers/block/loop.c | 33 ++++++++++++++++++--------------- > 1 file changed, 18 insertions(+), 15 deletions(-) Also just pushed a regression test to blktests: 140ee15de9f3 ("loop: add ioctl lock imbalance regression test")