In the Linux kernel, the following vulnerability has been resolved: MIPS: Don't crash in stack_top() for tasks without ABI or vDSO Not all tasks have an ABI associated or vDSO mapped, for example kthreads never do. If such a task ever ends up calling stack_top(), it will derefence the NULL ABI pointer and crash. This can for example happen when using kunit: mips_stack_top+0x28/0xc0 arch_pick_mmap_layout+0x190/0x220 kunit_vm_mmap_init+0xf8/0x138 __kunit_add_resource+0x40/0xa8 kunit_vm_mmap+0x88/0xd8 usercopy_test_init+0xb8/0x240 kunit_try_run_case+0x5c/0x1a8 kunit_generic_run_threadfn_adapter+0x28/0x50 kthread+0x118/0x240 ret_from_kernel_thread+0x14/0x1c Only dereference the ABI point if it is set. The GIC page is also included as it is specific to the vDSO. Also move the randomization adjustment into the same conditional.
https://git.kernel.org/stable/c/f22de2027b206ddfb8a075800bb5d0dacf2da4b8
https://git.kernel.org/stable/c/e9f4a6b3421e936c3ee9d74710243897d74dbaa2
https://git.kernel.org/stable/c/e78033e59444d257d095b73ce5d20625294f6ec2
https://git.kernel.org/stable/c/cddf47d20b0325dc8a4e57b833fe96e8f36c42a4
https://git.kernel.org/stable/c/bd90dbd196831f5c2620736dc221db2634cf1e8e
https://git.kernel.org/stable/c/ab18e48a503230d675e824a0d68a108bdff42503
https://git.kernel.org/stable/c/82d140f6aab5e89a9d3972697a0dbe1498752d9b
https://git.kernel.org/stable/c/5b6839b572b503609b9b58bc6c04a816eefa0794
https://git.kernel.org/stable/c/24d098b6f69b0aa806ffcb3e18259bee31650b28