[PATCH 3.12 013/111] HID: debug: fix error handling in hid_debug_events_read()

From: Jiri Slaby
Date: Wed Jun 10 2015 - 11:28:39 EST


From: Jiri Kosina <jkosina@xxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

commit 8fec02a73e31407e14986fca67dab48d4f777f0e upstream.

In the unlikely case of hdev vanishing while hid_debug_events_read() was
sleeping, we can't really break out of the case switch as with other cases,
as on the way out we'll try to remove ourselves from the hdev waitqueue.

Fix this by taking a shortcut exit path and avoiding cleanup that doesn't
make sense in case hdev doesn't exist any more anyway.

Reported-by: Jiri Slaby <jslaby@xxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
drivers/hid/hid-debug.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-debug.c b/drivers/hid/hid-debug.c
index 8453214ec376..c607d953270c 100644
--- a/drivers/hid/hid-debug.c
+++ b/drivers/hid/hid-debug.c
@@ -1027,7 +1027,8 @@ static ssize_t hid_debug_events_read(struct file *file, char __user *buffer,

if (!list->hdev || !list->hdev->debug) {
ret = -EIO;
- break;
+ set_current_state(TASK_RUNNING);
+ goto out;
}

/* allow O_NONBLOCK from other threads */
--
2.4.2

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