From: Shay Drory <shayd@xxxxxxxxxx>
[ Upstream commit def4cd43f522253645b72c97181399c241b54536 ]
Currently, polling a umad device will always works, even if the device was
disassociated. A disassociated device should immediately return EPOLLERR
from poll(). Otherwise userspace is endlessly hung on poll() with no idea
that the device has been removed from the system.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Link: https://lore.kernel.org/r/20210125121339.837518-3-leon@xxxxxxxxxx
Signed-off-by: Shay Drory <shayd@xxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/infiniband/core/user_mad.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/infiniband/core/user_mad.c b/drivers/infiniband/core/user_mad.c
index 7ec1918431f70..dd7f3b437c6be 100644
--- a/drivers/infiniband/core/user_mad.c
+++ b/drivers/infiniband/core/user_mad.c
@@ -397,6 +397,11 @@ static ssize_t ib_umad_read(struct file *filp, char __user *buf,
mutex_lock(&file->mutex);
}
+ if (file->agents_dead) {
+ mutex_unlock(&file->mutex);
+ return -EIO;
+ }
+
packet = list_entry(file->recv_list.next, struct ib_umad_packet, list);
list_del(&packet->list);
@@ -658,10 +663,14 @@ static __poll_t ib_umad_poll(struct file *filp, struct poll_table_struct *wait)
/* we will always be able to post a MAD send */
__poll_t mask = EPOLLOUT | EPOLLWRNORM;
+ mutex_lock(&file->mutex);
poll_wait(filp, &file->recv_wait, wait);
if (!list_empty(&file->recv_list))
mask |= EPOLLIN | EPOLLRDNORM;
+ if (file->agents_dead)
+ mask = EPOLLERR;
+ mutex_unlock(&file->mutex);
return mask;
}
@@ -1341,6 +1350,7 @@ static void ib_umad_kill_port(struct ib_umad_port *port)
list_for_each_entry(file, &port->file_list, port_list) {
mutex_lock(&file->mutex);
file->agents_dead = 1;
+ wake_up_interruptible(&file->recv_wait);
mutex_unlock(&file->mutex);
for (id = 0; id < IB_UMAD_MAX_AGENTS; ++id)
--
2.27.0
