Hello Masahiro Yamada,
The patch f71be9d084c9: "net: liquidio: fix mixed module-builtin
object" from Jun 7, 2023 (linux-next), leads to the following Smatch
static checker warning:
drivers/net/ethernet/cavium/liquidio/lio_main.c:810 liquidio_watchdog()
error: NULL dereference inside function 'module_refcount()'.
drivers/net/ethernet/cavium/liquidio/lio_main.c
800 disable_all_vf_links(other_oct);
801 all_vf_links_are_disabled = true;
802
803 #ifdef CONFIG_MODULE_UNLOAD
This code is old and buggy, but I think it's possibly the recent changes
which make this bug visible. Modules can be enabled but it doesn't mean
that this particular driver was built as a module. I think we want to
test #if MODULE as well?
804 vfs_mask1 = READ_ONCE(oct->sriov_info.vf_drv_loaded_mask);
805 vfs_mask2 = READ_ONCE(other_oct->sriov_info.vf_drv_loaded_mask);
806
807 vfs_referencing_pf = hweight64(vfs_mask1);
808 vfs_referencing_pf += hweight64(vfs_mask2);
809
--> 810 refcount = module_refcount(THIS_MODULE);
^^^^^^^^^^^
This will crash because THIS_MODULE is NULL when it's built in to the
kernel.
811 if (refcount >= vfs_referencing_pf) {
812 while (vfs_referencing_pf) {
813 module_put(THIS_MODULE);
814 vfs_referencing_pf--;
815 }
816 }
817 #endif
818 }
819
820 return 0;
821 }
regards,
dan carpenter
