4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael Guralnik <michaelgur@xxxxxxxxxx> [ Upstream commit ca0b44e20a6f3032224599f02e7c8fb49525c894 ] The existing behavior of ib_umad, which maintains received MAD packets in an unbounded list, poses a risk of uncontrolled growth. As user-space applications extract packets from this list, the rate of extraction may not match the rate of incoming packets, leading to potential list overflow. To address this, we introduce a limit to the size of the list. After considering typical scenarios, such as OpenSM processing, which can handle approximately 100k packets per second, and the 1-second retry timeout for most packets, we set the list size limit to 200k. Packets received beyond this limit are dropped, assuming they are likely timed out by the time they are handled by user-space. Notably, packets queued on the receive list due to reasons like timed-out sends are preserved even when the list is full. Signed-off-by: Michael Guralnik <michaelgur@xxxxxxxxxx> Reviewed-by: Mark Zhang <markzhang@xxxxxxxxxx> Link: https://lore.kernel.org/r/7197cb58a7d9e78399008f25036205ceab07fbd5.1713268818.git.leon@xxxxxxxxxx Signed-off-by: Leon Romanovsky <leon@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/infiniband/core/user_mad.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/drivers/infiniband/core/user_mad.c b/drivers/infiniband/core/user_mad.c index 471a824be86c4..bac1a589c822f 100644 --- a/drivers/infiniband/core/user_mad.c +++ b/drivers/infiniband/core/user_mad.c @@ -62,6 +62,8 @@ MODULE_AUTHOR("Roland Dreier"); MODULE_DESCRIPTION("InfiniBand userspace MAD packet access"); MODULE_LICENSE("Dual BSD/GPL"); +#define MAX_UMAD_RECV_LIST_SIZE 200000 + enum { IB_UMAD_MAX_PORTS = RDMA_MAX_PORTS, IB_UMAD_MAX_AGENTS = 32, @@ -113,6 +115,7 @@ struct ib_umad_file { struct mutex mutex; struct ib_umad_port *port; struct list_head recv_list; + atomic_t recv_list_size; struct list_head send_list; struct list_head port_list; spinlock_t send_lock; @@ -168,24 +171,28 @@ static struct ib_mad_agent *__get_agent(struct ib_umad_file *file, int id) return file->agents_dead ? NULL : file->agent[id]; } -static int queue_packet(struct ib_umad_file *file, - struct ib_mad_agent *agent, - struct ib_umad_packet *packet) +static int queue_packet(struct ib_umad_file *file, struct ib_mad_agent *agent, + struct ib_umad_packet *packet, bool is_recv_mad) { int ret = 1; mutex_lock(&file->mutex); + if (is_recv_mad && + atomic_read(&file->recv_list_size) > MAX_UMAD_RECV_LIST_SIZE) + goto unlock; + for (packet->mad.hdr.id = 0; packet->mad.hdr.id < IB_UMAD_MAX_AGENTS; packet->mad.hdr.id++) if (agent == __get_agent(file, packet->mad.hdr.id)) { list_add_tail(&packet->list, &file->recv_list); + atomic_inc(&file->recv_list_size); wake_up_interruptible(&file->recv_wait); ret = 0; break; } - +unlock: mutex_unlock(&file->mutex); return ret; @@ -212,7 +219,7 @@ static void send_handler(struct ib_mad_agent *agent, if (send_wc->status == IB_WC_RESP_TIMEOUT_ERR) { packet->length = IB_MGMT_MAD_HDR; packet->mad.hdr.status = ETIMEDOUT; - if (!queue_packet(file, agent, packet)) + if (!queue_packet(file, agent, packet, false)) return; } kfree(packet); @@ -272,7 +279,7 @@ static void recv_handler(struct ib_mad_agent *agent, rdma_destroy_ah_attr(&ah_attr); } - if (queue_packet(file, agent, packet)) + if (queue_packet(file, agent, packet, true)) goto err2; return; @@ -391,6 +398,7 @@ static ssize_t ib_umad_read(struct file *filp, char __user *buf, packet = list_entry(file->recv_list.next, struct ib_umad_packet, list); list_del(&packet->list); + atomic_dec(&file->recv_list_size); mutex_unlock(&file->mutex); @@ -403,6 +411,7 @@ static ssize_t ib_umad_read(struct file *filp, char __user *buf, /* Requeue packet */ mutex_lock(&file->mutex); list_add(&packet->list, &file->recv_list); + atomic_inc(&file->recv_list_size); mutex_unlock(&file->mutex); } else { if (packet->recv_wc) -- 2.43.0
