* [PATCH AUTOSEL 4.14 042/186] nbd: add a flush_workqueue in nbd_start_device
[not found] <20200214161715.18113-1-sashal@kernel.org>
@ 2020-02-14 16:14 ` Sasha Levin
2020-02-14 16:17 ` [PATCH AUTOSEL 4.14 182/186] brd: check and limit max_part par Sasha Levin
1 sibling, 0 replies; 2+ messages in thread
From: Sasha Levin @ 2020-02-14 16:14 UTC (permalink / raw)
To: linux-kernel, stable; +Cc: Sun Ke, Jens Axboe, Sasha Levin, linux-block, nbd
From: Sun Ke <sunke32@huawei.com>
[ 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 <sunke32@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/block/nbd.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 4c661ad91e7d3..8f56e6b2f114f 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1203,6 +1203,16 @@ static int nbd_start_device(struct nbd_device *nbd)
args = kzalloc(sizeof(*args), GFP_KERNEL);
if (!args) {
sock_shutdown(nbd);
+ /*
+ * If num_connections is m (2 < m),
+ * and NO.1 ~ NO.n(1 < n < m) kzallocs are successful.
+ * But NO.(n + 1) failed. We still have n recv threads.
+ * So, add flush_workqueue here to prevent recv threads
+ * dropping the last config_refs and trying to destroy
+ * the workqueue from inside the workqueue.
+ */
+ if (i)
+ flush_workqueue(nbd->recv_workq);
return -ENOMEM;
}
sk_set_memalloc(config->socks[i]->sock->sk);
--
2.20.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH AUTOSEL 4.14 182/186] brd: check and limit max_part par
[not found] <20200214161715.18113-1-sashal@kernel.org>
2020-02-14 16:14 ` [PATCH AUTOSEL 4.14 042/186] nbd: add a flush_workqueue in nbd_start_device Sasha Levin
@ 2020-02-14 16:17 ` Sasha Levin
1 sibling, 0 replies; 2+ messages in thread
From: Sasha Levin @ 2020-02-14 16:17 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Zhiqiang Liu, Bob Liu, Ming Lei, Jens Axboe, Sasha Levin, linux-block
From: Zhiqiang Liu <liuzhiqiang26@huawei.com>
[ Upstream commit c8ab422553c81a0eb070329c63725df1cd1425bc ]
In brd_init func, rd_nr num of brd_device are firstly allocated
and add in brd_devices, then brd_devices are traversed to add each
brd_device by calling add_disk func. When allocating brd_device,
the disk->first_minor is set to i * max_part, if rd_nr * max_part
is larger than MINORMASK, two different brd_device may have the same
devt, then only one of them can be successfully added.
when rmmod brd.ko, it will cause oops when calling brd_exit.
Follow those steps:
# modprobe brd rd_nr=3 rd_size=102400 max_part=1048576
# rmmod brd
then, the oops will appear.
Oops log:
[ 726.613722] Call trace:
[ 726.614175] kernfs_find_ns+0x24/0x130
[ 726.614852] kernfs_find_and_get_ns+0x44/0x68
[ 726.615749] sysfs_remove_group+0x38/0xb0
[ 726.616520] blk_trace_remove_sysfs+0x1c/0x28
[ 726.617320] blk_unregister_queue+0x98/0x100
[ 726.618105] del_gendisk+0x144/0x2b8
[ 726.618759] brd_exit+0x68/0x560 [brd]
[ 726.619501] __arm64_sys_delete_module+0x19c/0x2a0
[ 726.620384] el0_svc_common+0x78/0x130
[ 726.621057] el0_svc_handler+0x38/0x78
[ 726.621738] el0_svc+0x8/0xc
[ 726.622259] Code: aa0203f6 aa0103f7 aa1e03e0 d503201f (7940e260)
Here, we add brd_check_and_reset_par func to check and limit max_part par.
--
V5->V6:
- remove useless code
V4->V5:(suggested by Ming Lei)
- make sure max_part is not larger than DISK_MAX_PARTS
V3->V4:(suggested by Ming Lei)
- remove useless change
- add one limit of max_part
V2->V3: (suggested by Ming Lei)
- clear .minors when running out of consecutive minor space in brd_alloc
- remove limit of rd_nr
V1->V2:
- add more checks in brd_check_par_valid as suggested by Ming Lei.
Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Reviewed-by: Bob Liu <bob.liu@oracle.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/block/brd.c | 22 ++++++++++++++++++++--
1 file changed, 20 insertions(+), 2 deletions(-)
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 2d7178f7754ed..0129b1921cb36 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -529,6 +529,25 @@ static struct kobject *brd_probe(dev_t dev, int *part, void *data)
return kobj;
}
+static inline void brd_check_and_reset_par(void)
+{
+ if (unlikely(!max_part))
+ max_part = 1;
+
+ /*
+ * make sure 'max_part' can be divided exactly by (1U << MINORBITS),
+ * otherwise, it is possiable to get same dev_t when adding partitions.
+ */
+ if ((1U << MINORBITS) % max_part != 0)
+ max_part = 1UL << fls(max_part);
+
+ if (max_part > DISK_MAX_PARTS) {
+ pr_info("brd: max_part can't be larger than %d, reset max_part = %d.\n",
+ DISK_MAX_PARTS, DISK_MAX_PARTS);
+ max_part = DISK_MAX_PARTS;
+ }
+}
+
static int __init brd_init(void)
{
struct brd_device *brd, *next;
@@ -552,8 +571,7 @@ static int __init brd_init(void)
if (register_blkdev(RAMDISK_MAJOR, "ramdisk"))
return -EIO;
- if (unlikely(!max_part))
- max_part = 1;
+ brd_check_and_reset_par();
for (i = 0; i < rd_nr; i++) {
brd = brd_alloc(i);
--
2.20.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
end of thread, other threads:[~2020-02-14 16:55 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
[not found] <20200214161715.18113-1-sashal@kernel.org>
2020-02-14 16:14 ` [PATCH AUTOSEL 4.14 042/186] nbd: add a flush_workqueue in nbd_start_device Sasha Levin
2020-02-14 16:17 ` [PATCH AUTOSEL 4.14 182/186] brd: check and limit max_part par Sasha Levin
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).