linux-dev/arch/arc, branch linus/master

Merge tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2022-06-03T23:03:05Z

Pull kthread updates from Eric Biederman: "This updates init and user mode helper tasks to be ordinary user mode tasks. Commit 40966e316f86 ("kthread: Ensure struct kthread is present for all kthreads") caused init and the user mode helper threads that call kernel_execve to have struct kthread allocated for them. This struct kthread going away during execve in turned made a use after free of struct kthread possible. Here, commit 343f4c49f243 ("kthread: Don't allocate kthread_struct for init and umh") is enough to fix the use after free and is simple enough to be backportable. The rest of the changes pass struct kernel_clone_args to clean things up and cause the code to make sense. In making init and the user mode helpers tasks purely user mode tasks I ran into two complications. The function task_tick_numa was detecting tasks without an mm by testing for the presence of PF_KTHREAD. The initramfs code in populate_initrd_image was using flush_delayed_fput to ensuere the closing of all it's file descriptors was complete, and flush_delayed_fput does not work in a userspace thread. I have looked and looked and more complications and in my code review I have not found any, and neither has anyone else with the code sitting in linux-next" * tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: sched: Update task_tick_numa to ignore tasks without an mm fork: Stop allowing kthreads to call execve fork: Explicitly set PF_KTHREAD init: Deal with the init process being a user mode process fork: Generalize PF_IO_WORKER handling fork: Explicity test for idle tasks in copy_thread fork: Pass struct kernel_clone_args into copy_thread kthread: Don't allocate kthread_struct for init and umh

fork: Generalize PF_IO_WORKER handling

2022-05-07T14:01:59Z

Add fn and fn_arg members into struct kernel_clone_args and test for them in copy_thread (instead of testing for PF_KTHREAD | PF_IO_WORKER). This allows any task that wants to be a user space task that only runs in kernel mode to use this functionality. The code on x86 is an exception and still retains a PF_KTHREAD test because x86 unlikely everything else handles kthreads slightly differently than user space tasks that start with a function. The functions that created tasks that start with a function have been updated to set ".fn" and ".fn_arg" instead of ".stack" and ".stack_size". These functions are fork_idle(), create_io_thread(), kernel_thread(), and user_mode_thread(). Link: https://lkml.kernel.org/r/20220506141512.516114-4-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman"

fork: Pass struct kernel_clone_args into copy_thread

2022-05-07T14:01:48Z

With io_uring we have started supporting tasks that are for most purposes user space tasks that exclusively run code in kernel mode. The kernel task that exec's init and tasks that exec user mode helpers are also user mode tasks that just run kernel code until they call kernel execve. Pass kernel_clone_args into copy_thread so these oddball tasks can be supported more cleanly and easily. v2: Fix spelling of kenrel_clone_args on h8300 Link: https://lkml.kernel.org/r/20220506141512.516114-2-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman"

ARC: bpf: define uapi for BPF_PROG_TYPE_PERF_EVENT program type

2022-04-26T16:35:28Z

Define appropriate uapi for the BPF_PROG_TYPE_PERF_EVENT program type by exporting the user_regs_struct structure instead of the pt_regs structure that is in-kernel only. Signed-off-by: Sergey Matyukevich Signed-off-by: Vineet Gupta

ARC: disasm: handle ARCv2 case in kprobe get/set functions

2022-04-26T16:34:42Z

Current implementation of get_reg/set_reg implies ARCompact layout of pt_regs structure. Meanwhile pt_regs structure differs between ARCompact and ARCv2. Update those functions to handle ARCv2. Tested-by: kernel test robot Signed-off-by: Sergey Matyukevich Signed-off-by: Vineet Gupta

ARC: implement syscall tracepoints

2022-04-25T20:09:47Z

Implement all the bits required to support HAVE_SYSCALL_TRACEPOINTS according to Documentation/trace/ftrace-design.rst. Signed-off-by: Sergey Matyukevich Signed-off-by: Vineet Gupta

ARC: enable HAVE_REGS_AND_STACK_ACCESS_API feature

2022-04-25T20:09:47Z

Enable HAVE_REGS_AND_STACK_ACCESS_API feature for ARC architecture, including ARCcompact and ARCv2 flavors. Add supporting functions and defines. Signed-off-by: Sergey Matyukevich Signed-off-by: Vineet Gupta

ARC: remove redundant READ_ONCE() in cmpxchg loop

2022-04-18T21:47:05Z

This patch reverts commit 7082a29c22ac ("ARC: use ACCESS_ONCE in cmpxchg loop"). It is not necessary to use READ_ONCE() because cmpxchg contains barrier. We can get it from commit d57f727264f1 ("ARC: add compiler barrier to LLSC based cmpxchg"). Signed-off-by: Bang Li Signed-off-by: Vineet Gupta

ARC: atomic: cleanup atomic-llsc definitions

2022-04-18T21:45:09Z

Remove redundant c_op macro argument. Only asm_op is needed to define atomic operations using llock/scond. Signed-off-by: Sergey Matyukevich Signed-off-by: Vineet Gupta

arc: drop definitions of pgd_index() and pgd_offset{, _k}() entirely

2022-04-18T21:44:12Z

They were in and have been removed from there in 974b9b2c68f ("mm: consolidate pte_index() and pte_offset_*() definitions") in favor of the generic version. But that missed that the same definitons also existed in , where they were (inadvertently?) introduced in fe6cb7b043b6 ("ARC: mm: disintegrate pgtable.h into levels and flags"). Fixes: 974b9b2c68f3 ("mm: consolidate pte_index() and pte_offset_*() definitions") Fixes: fe6cb7b043b6 ("ARC: mm: disintegrate pgtable.h into levels and flags") Signed-off-by: Rolf Eike Beer Signed-off-by: Vineet Gupta