There is an ongoing discussion [1] about the need to fix use of probe_kernel_address in task_rcu_deference (or provide additional existence guarantees), and add missing READ_ONCE and probe_kernel_address when reading other cpu runqueue's mm->membarrier_state.
This patch set simply adds the missing probe_kernel_address checks and use, aiming to be easily backported to stable kernels. Changing the existence guarantees of sighand and mm objects is expected to deprecate those changes for future kernels, but it's unclear whether those more intrusive changes will be acceptable for stable kernel branches. Thanks, Mathieu [1] https://lore.kernel.org/r/[email protected] Mathieu Desnoyers (3): Fix: sched: task_rcu_dereference: check probe_kernel_address return value Fix: sched/membarrier: READ_ONCE p->mm in membarrier_global_expedited Fix: sched/membarrier: use probe_kernel_address to read mm->membarrier_state kernel/exit.c | 3 ++- kernel/sched/membarrier.c | 27 +++++++++++++++++++++++++-- 2 files changed, 27 insertions(+), 3 deletions(-) -- 2.17.1
