alistair23-linux/arch/arm
Linus Torvalds 83fa805bcb threads-v5.6
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Merge tag 'threads-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux

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
2020-01-29 19:38:34 -08:00
..
boot USB/Thunderbolt/PHY driver updates for 5.6-rc1 2020-01-29 10:09:44 -08:00
common ARM: scoop: Use the right include 2019-09-03 22:09:46 +02:00
configs ARM: configs: Build BCM2711 thermal as module 2020-01-27 11:41:08 +01:00
crypto crypto: arm/chacha - fix build failured when kernel mode NEON is disabled 2020-01-22 16:21:11 +08:00
include Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2020-01-28 10:07:09 -08:00
kernel TTY/Serial driver updates for 5.6-rc1 2020-01-29 10:13:27 -08:00
kvm Merge remote-tracking branch 'kvmarm/misc-5.5' into kvmarm/next 2019-11-08 11:27:29 +00:00
lib Merge branch 'misc' into fixes 2019-10-22 17:37:29 +01:00
mach-actions
mach-alpine
mach-artpec
mach-asm9260
mach-aspeed ARM: SoC fixes 2019-09-30 10:04:28 -07:00
mach-at91 ARM: at91: move platform-specific asm-offset.h to arch/arm/mach-at91 2019-08-23 21:50:10 +02:00
mach-axxia
mach-bcm remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
mach-berlin
mach-clps711x
mach-cns3xxx
mach-davinci USB/Thunderbolt/PHY driver updates for 5.6-rc1 2020-01-29 10:09:44 -08:00
mach-digicolor
mach-dove
mach-ebsa110
mach-efm32
mach-ep93xx Merge branch 'spi-5.4' into spi-next 2019-09-15 10:32:06 +01:00
mach-exynos irqchip: Define EXYNOS_IRQ_COMBINER 2020-01-20 19:10:05 +00:00
mach-footbridge ARM: 8911/1: move pcibios_report_status to <asm/pci.h> 2019-10-27 21:14:40 +00:00
mach-gemini
mach-highbank
mach-hisi ARM: hisi: drop useless depend on ARCH_MULTI_V7 2019-10-26 15:31:22 +08:00
mach-imx ARM: imx: Fix boot crash if ocotp is not found 2019-12-12 10:44:28 +08:00
mach-integrator
mach-iop32x
mach-ixp4xx ARM/net: ixp4xx: Pass ethernet physical base as resource 2020-01-12 12:59:53 -08:00
mach-keystone
mach-lpc18xx
mach-lpc32xx
mach-mediatek
mach-meson
mach-milbeaut
mach-mmp ARM: mmp: do not divide the clock rate 2020-01-06 09:18:50 -08:00
mach-moxart
mach-mv78xx0
mach-mvebu
mach-mxs
mach-nomadik
mach-npcm
mach-nspire
mach-omap1 ARM: OMAP1: drop duplicated dependency on ARCH_OMAP1 2019-11-11 12:30:39 -08:00
mach-omap2 ARM: omap2plus: select RESET_CONTROLLER 2020-01-08 10:24:05 -08:00
mach-orion5x
mach-oxnas
mach-picoxcell
mach-prima2
mach-pxa USB/Thunderbolt/PHY driver updates for 5.6-rc1 2020-01-29 10:09:44 -08:00
mach-qcom
mach-rda
mach-realview
mach-rockchip
mach-rpc ARM: riscpc: Mark expected switch fall-through 2019-08-20 19:42:48 -05:00
mach-s3c24xx ARM: s3c: Rename s3c64xx_spi_setname() function 2019-10-28 17:46:57 +01:00
mach-s3c64xx usb: phy: phy-gpio-vbus-usb: Convert to GPIO descriptors 2020-01-23 19:20:57 +01:00
mach-s5pv210
mach-sa1100
mach-shmobile remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
mach-socfpga arm: socfpga: execute cold reboot by default 2019-11-22 12:12:10 -06:00
mach-spear
mach-sti
mach-stm32
mach-sunxi ARM: sunxi: Fix CPU powerdown on A83T 2019-10-29 09:09:56 +01:00
mach-tango
mach-tegra ARM: SoC platform updates 2019-12-05 11:38:40 -08:00
mach-u300 pinctrl: Allow modules to use pinctrl_[un]register_mappings 2019-12-30 14:27:17 +01:00
mach-uniphier
mach-ux500 mfd: db8500-prcmu: Support U8420-sysclk firmware 2019-11-11 08:45:04 +00:00
mach-versatile
mach-vexpress ARM: vexpress: Set-up shared OPP table instead of individual for each CPU 2019-12-09 11:52:50 +00:00
mach-vt8500
mach-zx
mach-zynq
mm Linux 5.5-rc3 2019-12-25 10:41:37 +01:00
net ARM: net: bpf: Improve prologue code sequence 2019-12-11 14:34:26 +01:00
nwfpe
oprofile
plat-omap
plat-orion
plat-pxa spi: pxa2xx: No need to keep pointer to platform device 2019-10-18 18:24:50 +01:00
plat-samsung ARM: s3c: Rename s5p_usb_phy functions 2019-10-28 17:46:58 +01:00
plat-versatile
probes
tools threads-v5.6 2020-01-29 19:38:34 -08:00
vdso ARM: vdso: Set BUILD_VDSO32 and provide 32bit fallbacks 2020-01-14 12:20:43 +01:00
vfp
xen dma-mapping updates for 5.5-rc1 2019-11-28 11:16:43 -08:00
Kconfig Merge branch 'core-objtool-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2020-01-28 08:38:25 -08:00
Kconfig-nommu
Kconfig.debug ARM updates for 5.4-rc1: 2019-09-22 09:39:09 -07:00
Makefile ARM updates for 5.4-rc1: 2019-09-22 09:39:09 -07:00