On Mon, Mar 10, 2025 at 02:43:51PM +0200, Ilpo Järvinen wrote: > On Mon, 10 Mar 2025, Dan Carpenter wrote: > > > There are a couple problems in this code: > > > > First, if amd_pmf_tee_init() fails then the function returns directly > > instead of cleaning up. We cannot simply do a "goto error;" because > > that would lead to a double free. I have re-written this code to > > use an unwind ladder to free the allocations. > > Thanks Dan, > > Could you please amend this with the information of what is getting > double freed, it took considerable amount of time for me to figure out. > I assume it's ->fw_shm_pool ? > Yes, that's it. Sure, I can re-write that. > > Second, if amd_pmf_start_policy_engine() fails on every iteration though > > the loop then the code calls amd_pmf_tee_deinit() twice which is also a > > double free. Call amd_pmf_tee_deinit() inside the loop for each failed > > iteration. Also on that path the error codes are not necessarily > > negative kernel error codes. Set the error code to -EINVAL. > > Maybe I should start to consistently reject any attempt to use > cleanup/deinit helper functions instead of a proper rollback. It > seems a pattern that is very prone to errors like this. I do not like deinit functions. They are so hard to review. But I detected this bug because of a Smatch warning: drivers/platform/x86/amd/pmf/tee-if.c:540 amd_pmf_init_smart_pc() warn: missing unwind goto? regards, dan carpenter
