diff options
author | Yong Ding <yongding@codeaurora.org> | 2018-10-17 20:08:35 +0800 |
---|---|---|
committer | Yong Ding <yongding@codeaurora.org> | 2018-10-23 09:08:34 +0800 |
commit | bc856c7cae7e9b4b4d03238d4ad9f778889656b5 (patch) | |
tree | bf041f5d9a34a8b2a82c050d2c00a2a6e6d3da67 /drivers/soc | |
parent | 85edf1b9737dce14f19084437bb389709d1aa069 (diff) |
soc: qcom: hab: add rx queue empty check after getting the lock
Need to do empty check again when we have the lock of the rx queue of
a given virtual channel. Without this check, it is possible that the
list head of the queue will be wrongly taken as a valid message node
if the valid message has already been fetched by some other thread.
Change-Id: I65f73acd86fe2fb709e2af2ffeaa42581b4168ca
Signed-off-by: Yong Ding <yongding@codeaurora.org>
Diffstat (limited to 'drivers/soc')
-rw-r--r-- | drivers/soc/qcom/hab/hab_msg.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/drivers/soc/qcom/hab/hab_msg.c b/drivers/soc/qcom/hab/hab_msg.c index 61e658954312..71010be414d5 100644 --- a/drivers/soc/qcom/hab/hab_msg.c +++ b/drivers/soc/qcom/hab/hab_msg.c @@ -64,9 +64,14 @@ hab_msg_dequeue(struct virtual_channel *vchan, struct hab_message **msg, } } - /* return all the received messages before the remote close */ - if ((!ret || (ret == -ERESTARTSYS)) && !hab_rx_queue_empty(vchan)) { - spin_lock_bh(&vchan->rx_lock); + /* + * return all the received messages before the remote close, + * and need empty check again in case the list is empty now due to + * dequeue by other threads + */ + spin_lock_bh(&vchan->rx_lock); + + if ((!ret || (ret == -ERESTARTSYS)) && !list_empty(&vchan->rx_list)) { message = list_first_entry(&vchan->rx_list, struct hab_message, node); if (message) { @@ -84,11 +89,12 @@ hab_msg_dequeue(struct virtual_channel *vchan, struct hab_message **msg, ret = -EOVERFLOW; /* come back again */ } } - spin_unlock_bh(&vchan->rx_lock); } else /* no message received, retain the original status */ *rsize = 0; + spin_unlock_bh(&vchan->rx_lock); + *msg = message; return ret; } |