kernel/linux.git/drivers/block/nbd.c, branch v4.19.112

nbd: add a flush_workqueue in nbd_start_device

2020-02-24T07:34:39+00:00

[ Upstream commit 5c0dd228b5fc30a3b732c7ae2657e0161ec7ed80 ] When kzalloc fail, may cause trying to destroy the workqueue from inside the workqueue. If num_connections is m (2 < m), and NO.1 ~ NO.n (1 < n < m) kzalloc are successful. The NO.(n + 1) failed. Then, nbd_start_device will return ENOMEM to nbd_start_device_ioctl, and nbd_start_device_ioctl will return immediately without running flush_workqueue. However, we still have n recv threads. If nbd_release run first, recv threads may have to drop the last config_refs and try to destroy the workqueue from inside the workqueue. To fix it, add a flush_workqueue in nbd_start_device. Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs") Signed-off-by: Sun Ke Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

nbd: fix shutdown and recv work deadlock v2

2019-12-31T15:36:36+00:00

commit 1c05839aa973cfae8c3db964a21f9c0eef8fcc21 upstream. This fixes a regression added with: commit e9e006f5fcf2bab59149cb38a48a4817c1b538b4 Author: Mike Christie Date: Sun Aug 4 14:10:06 2019 -0500 nbd: fix max number of supported devs where we can deadlock during device shutdown. The problem occurs if the recv_work's nbd_config_put occurs after nbd_start_device_ioctl has returned and the userspace app has droppped its reference via closing the device and running nbd_release. The recv_work nbd_config_put call would then drop the refcount to zero and try to destroy the config which would try to do destroy_workqueue from the recv work. This patch just has nbd_start_device_ioctl do a flush_workqueue when it wakes so we know after the ioctl returns running works have exited. This also fixes a possible race where we could try to reuse the device while old recv_works are still running. Cc: stable@vger.kernel.org Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs") Signed-off-by: Mike Christie Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

nbd: prevent memory leak

2019-12-01T08:17:38+00:00

commit 03bf73c315edca28f47451913177e14cd040a216 upstream. In nbd_add_socket when krealloc succeeds, if nsock's allocation fail the reallocted memory is leak. The correct behaviour should be assigning the reallocted memory to config->socks right after success. Reviewed-by: Josef Bacik Signed-off-by: Navid Emamdoost Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

nbd:fix memory leak in nbd_get_socket()

2019-12-01T08:16:09+00:00

commit dff10bbea4be47bdb615b036c834a275b7c68133 upstream. Before returning NULL, put the sock first. Cc: stable@vger.kernel.org Fixes: cf1b2326b734 ("nbd: verify socket is supported during setup") Reviewed-by: Josef Bacik Reviewed-by: Mike Christie Signed-off-by: Sun Ke Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

nbd: handle racing with error'ed out commands

2019-11-10T10:27:35+00:00

[ Upstream commit 7ce23e8e0a9cd38338fc8316ac5772666b565ca9 ] We hit the following warning in production print_req_error: I/O error, dev nbd0, sector 7213934408 flags 80700 ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 25 PID: 32407 at lib/refcount.c:190 refcount_sub_and_test_checked+0x53/0x60 Workqueue: knbd-recv recv_work [nbd] RIP: 0010:refcount_sub_and_test_checked+0x53/0x60 Call Trace: blk_mq_free_request+0xb7/0xf0 blk_mq_complete_request+0x62/0xf0 recv_work+0x29/0xa1 [nbd] process_one_work+0x1f5/0x3f0 worker_thread+0x2d/0x3d0 ? rescuer_thread+0x340/0x340 kthread+0x111/0x130 ? kthread_create_on_node+0x60/0x60 ret_from_fork+0x1f/0x30 ---[ end trace b079c3c67f98bb7c ]--- This was preceded by us timing out everything and shutting down the sockets for the device. The problem is we had a request in the queue at the same time, so we completed the request twice. This can actually happen in a lot of cases, we fail to get a ref on our config, we only have one connection and just error out the command, etc. Fix this by checking cmd->status in nbd_read_stat. We only change this under the cmd->lock, so we are safe to check this here and see if we've already error'ed this command out, which would indicate that we've completed it as well. Reviewed-by: Mike Christie Signed-off-by: Josef Bacik Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

nbd: protect cmd->status with cmd->lock

2019-11-10T10:27:34+00:00

[ Upstream commit de6346ecbc8f5591ebd6c44ac164e8b8671d71d7 ] We already do this for the most part, except in timeout and clear_req. For the timeout case we take the lock after we grab a ref on the config, but that isn't really necessary because we're safe to touch the cmd at this point, so just move the order around. For the clear_req cause this is initiated by the user, so again is safe. Reviewed-by: Mike Christie Signed-off-by: Josef Bacik Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

nbd: verify socket is supported during setup

2019-11-06T12:06:11+00:00

[ Upstream commit cf1b2326b734896734c6e167e41766f9cee7686a ] nbd requires socket families to support the shutdown method so the nbd recv workqueue can be woken up from its sock_recvmsg call. If the socket does not support the callout we will leave recv works running or get hangs later when the device or module is removed. This adds a check during socket connection/reconnection to make sure the socket being passed in supports the needed callout. Reported-by: syzbot+24c12fa8d218ed26011a@syzkaller.appspotmail.com Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs") Tested-by: Richard W.M. Jones Signed-off-by: Mike Christie Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

nbd: fix possible sysfs duplicate warning

2019-11-06T12:06:07+00:00

[ Upstream commit 862488105b84ca744b3d8ff131e0fcfe10644be1 ] 1. nbd_put takes the mutex and drops nbd->ref to 0. It then does idr_remove and drops the mutex. 2. nbd_genl_connect takes the mutex. idr_find/idr_for_each fails to find an existing device, so it does nbd_dev_add. 3. just before the nbd_put could call nbd_dev_remove or not finished totally, but if nbd_dev_add try to add_disk, we can hit: debugfs: Directory 'nbd1' with parent 'block' already present! This patch will make sure all the disk add/remove stuff are done by holding the nbd_index_mutex lock. Reported-by: Mike Christie Reviewed-by: Josef Bacik Signed-off-by: Xiubo Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

nbd: fix crash when the blksize is zero

2019-10-11T16:21:26+00:00

[ Upstream commit 553768d1169a48c0cd87c4eb4ab57534ee663415 ] This will allow the blksize to be set zero and then use 1024 as default. Reviewed-by: Josef Bacik Signed-off-by: Xiubo Li [fix to use goto out instead of return in genl_connect] Signed-off-by: Mike Christie Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

nbd: fix max number of supported devs

2019-10-11T16:20:46+00:00

commit e9e006f5fcf2bab59149cb38a48a4817c1b538b4 upstream. This fixes a bug added in 4.10 with commit: commit 9561a7ade0c205bc2ee035a2ac880478dcc1a024 Author: Josef Bacik Date: Tue Nov 22 14:04:40 2016 -0500 nbd: add multi-connection support that limited the number of devices to 256. Before the patch we could create 1000s of devices, but the patch switched us from using our own thread to using a work queue which has a default limit of 256 active works. The problem is that our recv_work function sits in a loop until disconnection but only handles IO for one connection. The work is started when the connection is started/restarted, but if we end up creating 257 or more connections, the queue_work call just queues connection257+'s recv_work and that waits for connection 1 - 256's recv_work to be disconnected and that work instance completing. Instead of reverting back to kthreads, this has us allocate a workqueue_struct per device, so we can block in the work. Cc: stable@vger.kernel.org Reviewed-by: Josef Bacik Signed-off-by: Mike Christie Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman