OPP: fix dev_pm_opp_find_bw_*() when bandwidth table not initialized

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: OPP: fix dev_pm_opp_find_bw_*() when bandwidth table not initialized If a driver calls dev_pm_opp_find_bw_ceil/floor() the retrieve bandwidth from the OPP table but the bandwidth table was not created because the interconnect properties were missing in the OPP consumer node, the kernel will crash with: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004 ... pc : _read_bw+0x8/0x10 lr : _opp_table_find_key+0x9c/0x174 ... Call trace: _read_bw+0x8/0x10 (P) _opp_table_find_key+0x9c/0x174 (L) _find_key+0x98/0x168 dev_pm_opp_find_bw_ceil+0x50/0x88 ... In order to fix the crash, create an assert function to check if the bandwidth table was created before trying to get a bandwidth with _read_bw().

References

• https://git.kernel.org/stable/c/8532fd078d2a5286915d03bb0a0893ee1955acef
• https://git.kernel.org/stable/c/84ff05c9bd577157baed711a4f0b41206593978b
• https://git.kernel.org/stable/c/ff2def251849133be6076a7c2d427d8eb963c223
• https://git.kernel.org/stable/c/5165486681dbd67b61b975c63125f2a5cb7f96d1
• https://git.kernel.org/stable/c/b44b9bc7cab2967c3d6a791b1cd542c89fc07f0e