6.8-stable review patch. If anyone has any objections, please let me know.
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From: Kwangjin Ko kwangjin.ko@sk.com
[ Upstream commit f7c52345ccc96343c0a05bdea3121c8ac7b67d5f ]
Since mbox_cmd.size_out is overwritten with the actual output size in the function below, it needs to be initialized every time.
cxl_internal_send_cmd -> __cxl_pci_mbox_send_cmd
Problem scenario:
1) The size_out variable is initially set to the size of the mailbox. 2) Read an event. - size_out is set to 160 bytes(header 32B + one event 128B). - Two event are created while reading. 3) Read the new *two* events. - size_out is still set to 160 bytes. - Although the value of out_len is 288 bytes, only 160 bytes are copied from the mailbox register to the local variable. - record_count is set to 2. - Accessing records[1] will result in reading incorrect data.
Fixes: 6ebe28f9ec72 ("cxl/mem: Read, trace, and clear events on driver load") Tested-by: Ira Weiny ira.weiny@intel.com Reviewed-by: Ira Weiny ira.weiny@intel.com Reviewed-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Kwangjin Ko kwangjin.ko@sk.com Signed-off-by: Dave Jiang dave.jiang@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/cxl/core/mbox.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c index 50146161887d5..f0f54aeccc872 100644 --- a/drivers/cxl/core/mbox.c +++ b/drivers/cxl/core/mbox.c @@ -958,13 +958,14 @@ static void cxl_mem_get_records_log(struct cxl_memdev_state *mds, .payload_in = &log_type, .size_in = sizeof(log_type), .payload_out = payload, - .size_out = mds->payload_size, .min_out = struct_size(payload, records, 0), };
do { int rc, i;
+ mbox_cmd.size_out = mds->payload_size; + rc = cxl_internal_send_cmd(mds, &mbox_cmd); if (rc) { dev_err_ratelimited(dev,