2019-05-04 18:41:02

by Matias Bjørling

[permalink] [raw]
Subject: [GIT PULL 13/26] lightnvm: prevent race condition on pblk remove

From: Marcin Dziegielewski <[email protected]>

When we trigger nvm target remove during device hot unplug, there is
a probability to hit a general protection fault. This is caused by use
of nvm_dev thay may be freed from another (hot unplug) thread
(in the nvm_unregister function).

Introduce lock in nvme_ioctl_dev_remove function to prevent this
situation.

Signed-off-by: Marcin Dziegielewski <[email protected]>
Reviewed-by: Javier González <[email protected]>
Signed-off-by: Matias Bjørling <[email protected]>
---
drivers/lightnvm/core.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index c01f83b8fbaf..e2abe88a139c 100644
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -1340,11 +1340,13 @@ static long nvm_ioctl_dev_remove(struct file *file, void __user *arg)
return -EINVAL;
}

+ down_read(&nvm_lock);
list_for_each_entry(dev, &nvm_devices, devices) {
ret = nvm_remove_tgt(dev, &remove);
if (!ret)
break;
}
+ up_read(&nvm_lock);

return ret;
}
--
2.19.1