1. 31 Jan, 2020 37 commits
  2. 30 Jan, 2020 3 commits
    • Linus Torvalds's avatar
      Merge tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma · 39bed42d
      Linus Torvalds authored
      Pull mmu_notifier updates from Jason Gunthorpe:
       "This small series revises the names in mmu_notifier to make the code
        clearer and more readable"
      
      * tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
        mm/mmu_notifiers: Use 'interval_sub' as the variable for mmu_interval_notifier
        mm/mmu_notifiers: Use 'subscription' as the variable name for mmu_notifier
        mm/mmu_notifier: Rename struct mmu_notifier_mm to mmu_notifier_subscriptions
      39bed42d
    • Linus Torvalds's avatar
      Merge tag 'threads-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux · 83fa805b
      Linus Torvalds authored
      Pull thread management updates from Christian Brauner:
       "Sargun Dhillon over the last cycle has worked on the pidfd_getfd()
        syscall.
      
        This syscall allows for the retrieval of file descriptors of a process
        based on its pidfd. A task needs to have ptrace_may_access()
        permissions with PTRACE_MODE_ATTACH_REALCREDS (suggested by Oleg and
        Andy) on the target.
      
        One of the main use-cases is in combination with seccomp's user
        notification feature. As a reminder, seccomp's user notification
        feature was made available in v5.0. It allows a task to retrieve a
        file descriptor for its seccomp filter. The file descriptor is usually
        handed of to a more privileged supervising process. The supervisor can
        then listen for syscall events caught by the seccomp filter of the
        supervisee and perform actions in lieu of the supervisee, usually
        emulating syscalls. pidfd_getfd() is needed to expand its uses.
      
        There are currently two major users that wait on pidfd_getfd() and one
        future user:
      
         - Netflix, Sargun said, is working on a service mesh where users
           should be able to connect to a dns-based VIP. When a user connects
           to e.g. 1.2.3.4:80 that runs e.g. service "foo" they will be
           redirected to an envoy process. This service mesh uses seccomp user
           notifications and pidfd to intercept all connect calls and instead
           of connecting them to 1.2.3.4:80 connects them to e.g.
           127.0.0.1:8080.
      
         - LXD uses the seccomp notifier heavily to intercept and emulate
           mknod() and mount() syscalls for unprivileged containers/processes.
           With pidfd_getfd() more uses-cases e.g. bridging socket connections
           will be possible.
      
         - The patchset has also seen some interest from the browser corner.
           Right now, Firefox is using a SECCOMP_RET_TRAP sandbox managed by a
           broker process. In the future glibc will start blocking all signals
           during dlopen() rendering this type of sandbox impossible. Hence,
           in the future Firefox will switch to a seccomp-user-nofication
           based sandbox which also makes use of file descriptor retrieval.
           The thread for this can be found at
           https://sourceware.org/ml/libc-alpha/2019-12/msg00079.html
      
        With pidfd_getfd() it is e.g. possible to bridge socket connections
        for the supervisee (binding to a privileged port) and taking actions
        on file descriptors on behalf of the supervisee in general.
      
        Sargun's first version was using an ioctl on pidfds but various people
        pushed for it to be a proper syscall which he duely implemented as
        well over various review cycles. Selftests are of course included.
        I've also added instructions how to deal with merge conflicts below.
      
        There's also a small fix coming from the kernel mentee project to
        correctly annotate struct sighand_struct with __rcu to fix various
        sparse warnings. We've received a few more such fixes and even though
        they are mostly trivial I've decided to postpone them until after -rc1
        since they came in rather late and I don't want to risk introducing
        build warnings.
      
        Finally, there's a new prctl() command PR_{G,S}ET_IO_FLUSHER which is
        needed to avoid allocation recursions triggerable by storage drivers
        that have userspace parts that run in the IO path (e.g. dm-multipath,
        iscsi, etc). These allocation recursions deadlock the device.
      
        The new prctl() allows such privileged userspace components to avoid
        allocation recursions by setting the PF_MEMALLOC_NOIO and
        PF_LESS_THROTTLE flags. The patch carries the necessary acks from the
        relevant maintainers and is routed here as part of prctl()
        thread-management."
      
      * tag 'threads-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
        prctl: PR_{G,S}ET_IO_FLUSHER to support controlling memory reclaim
        sched.h: Annotate sighand_struct with __rcu
        test: Add test for pidfd getfd
        arch: wire up pidfd_getfd syscall
        pid: Implement pidfd_getfd syscall
        vfs, fdtable: Add fget_task helper
      83fa805b
    • Linus Torvalds's avatar
      Merge tag 'for-5.6/io_uring-vfs-2020-01-29' of git://git.kernel.dk/linux-block · 896f8d23
      Linus Torvalds authored
      Pull io_uring updates from Jens Axboe:
      
       - Support for various new opcodes (fallocate, openat, close, statx,
         fadvise, madvise, openat2, non-vectored read/write, send/recv, and
         epoll_ctl)
      
       - Faster ring quiesce for fileset updates
      
       - Optimizations for overflow condition checking
      
       - Support for max-sized clamping
      
       - Support for probing what opcodes are supported
      
       - Support for io-wq backend sharing between "sibling" rings
      
       - Support for registering personalities
      
       - Lots of little fixes and improvements
      
      * tag 'for-5.6/io_uring-vfs-2020-01-29' of git://git.kernel.dk/linux-block: (64 commits)
        io_uring: add support for epoll_ctl(2)
        eventpoll: support non-blocking do_epoll_ctl() calls
        eventpoll: abstract out epoll_ctl() handler
        io_uring: fix linked command file table usage
        io_uring: support using a registered personality for commands
        io_uring: allow registering credentials
        io_uring: add io-wq workqueue sharing
        io-wq: allow grabbing existing io-wq
        io_uring/io-wq: don't use static creds/mm assignments
        io-wq: make the io_wq ref counted
        io_uring: fix refcounting with batched allocations at OOM
        io_uring: add comment for drain_next
        io_uring: don't attempt to copy iovec for READ/WRITE
        io_uring: honor IOSQE_ASYNC for linked reqs
        io_uring: prep req when do IOSQE_ASYNC
        io_uring: use labeled array init in io_op_defs
        io_uring: optimise sqe-to-req flags translation
        io_uring: remove REQ_F_IO_DRAINED
        io_uring: file switch work needs to get flushed on exit
        io_uring: hide uring_fd in ctx
        ...
      896f8d23