From: Zhang Yuchen zhangyuchen.lcr@bytedance.com
[ Upstream commit 36992eb6b9b83f7f9cdc8e74fb5799d7b52e83e9 ]
After the IPMI disconnect problem, the memory kept rising and we tried to unload the driver to free the memory. However, only part of the free memory is recovered after the driver is uninstalled. Using ebpf to hook free functions, we find that neither ipmi_user nor ipmi_smi_msg is free, only ipmi_recv_msg is free.
We find that the deliver_smi_err_response call in clean_smi_msgs does the destroy processing on each message from the xmit_msg queue without checking the return value and free ipmi_smi_msg.
deliver_smi_err_response is called only at this location. Adding the free handling has no effect.
To verify, try using ebpf to trace the free function.
$ bpftrace -e 'kretprobe:ipmi_alloc_recv_msg {printf("alloc rcv %p\n",retval);} kprobe:free_recv_msg {printf("free recv %p\n", arg0)} kretprobe:ipmi_alloc_smi_msg {printf("alloc smi %p\n", retval);} kprobe:free_smi_msg {printf("free smi %p\n",arg0)}'
Signed-off-by: Zhang Yuchen zhangyuchen.lcr@bytedance.com Message-Id: 20221007092617.87597-4-zhangyuchen.lcr@bytedance.com [Fixed the comment above handle_one_recv_msg().] Signed-off-by: Corey Minyard cminyard@mvista.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/char/ipmi/ipmi_msghandler.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c index 736970312bbc..55f38058c0b4 100644 --- a/drivers/char/ipmi/ipmi_msghandler.c +++ b/drivers/char/ipmi/ipmi_msghandler.c @@ -3535,12 +3535,16 @@ static void deliver_smi_err_response(struct ipmi_smi *intf, struct ipmi_smi_msg *msg, unsigned char err) { + int rv; msg->rsp[0] = msg->data[0] | 4; msg->rsp[1] = msg->data[1]; msg->rsp[2] = err; msg->rsp_size = 3; - /* It's an error, so it will never requeue, no need to check return. */ - handle_one_recv_msg(intf, msg); + + /* This will never requeue, but it may ask us to free the message. */ + rv = handle_one_recv_msg(intf, msg); + if (rv == 0) + ipmi_free_smi_msg(msg); }
static void cleanup_smi_msgs(struct ipmi_smi *intf)