In the Linux kernel, the following vulnerability has been resolved:
smb/client: avoid possible NULL dereference in cifsfreesubrequest()
Clang static checker (scan-build) warning: cifsglob.h:line 890, column 3 Access to field 'ops' results in a dereference of a null pointer.
Commit 519be989717c ("cifs: Add a tracepoint to track credits involved in R/W requests") adds a check for 'rdata->server', and let clang throw this warning about NULL dereference.
When 'rdata->credits.value != 0 && rdata->server == NULL' happens, addcreditsandwakeif() will call rdata->server->ops->add_credits(). This will cause NULL dereference problem. Add a check for 'rdata->server' to avoid NULL dereference.