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[157.230.128.187]) by smtp.gmail.com with ESMTPSA id iq3sm103489pjb.6.2020.06.08.10.01.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 08 Jun 2020 10:01:32 -0700 (PDT) Received: by 42.do-not-panic.com (Postfix, from userid 1000) id 9045A41DD1; Mon, 8 Jun 2020 17:01:28 +0000 (UTC) From: Luis Chamberlain To: axboe@kernel.dk, viro@zeniv.linux.org.uk, bvanassche@acm.org, gregkh@linuxfoundation.org, rostedt@goodmis.org, mingo@redhat.com, jack@suse.cz, ming.lei@redhat.com, nstange@suse.de, akpm@linux-foundation.org Cc: mhocko@suse.com, yukuai3@huawei.com, martin.petersen@oracle.com, jejb@linux.ibm.com, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Luis Chamberlain , Christoph Hellwig Subject: [PATCH v6 5/6] loop: be paranoid on exit and prevent new additions / removals Date: Mon, 8 Jun 2020 17:01:25 +0000 Message-Id: <20200608170127.20419-6-mcgrof@kernel.org> X-Mailer: git-send-email 2.23.0.rc1 In-Reply-To: <20200608170127.20419-1-mcgrof@kernel.org> References: <20200608170127.20419-1-mcgrof@kernel.org> MIME-Version: 1.0 X-Rspamd-Queue-Id: C079D181D376F X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Be pedantic on removal as well and hold the mutex. This should prevent uses of addition while we exit. Reviewed-by: Ming Lei Reviewed-by: Christoph Hellwig Signed-off-by: Luis Chamberlain --- drivers/block/loop.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index c33bbbfd1bd9..d55e1b52f076 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -2402,6 +2402,8 @@ static void __exit loop_exit(void) =20 range =3D max_loop ? max_loop << part_shift : 1UL << MINORBITS; =20 + mutex_lock(&loop_ctl_mutex); + idr_for_each(&loop_index_idr, &loop_exit_cb, NULL); idr_destroy(&loop_index_idr); =20 @@ -2409,6 +2411,8 @@ static void __exit loop_exit(void) unregister_blkdev(LOOP_MAJOR, "loop"); =20 misc_deregister(&loop_misc); + + mutex_unlock(&loop_ctl_mutex); } =20 module_init(loop_init); --=20 2.26.2