kernel_optimize_test/arch/mips
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
..
alchemy treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 182 2019-05-30 11:29:20 -07:00
ar7 remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
ath25 remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
ath79 remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
bcm47xx MIPS: BCM47XX: Add support for Netgear R6200 V1 2019-07-25 22:10:05 -07:00
bcm63xx MIPS: bmips: mark exception vectors as char arrays 2019-10-23 21:07:28 -07:00
bmips dma-mapping: drop the dev argument to arch_sync_dma_for_* 2019-11-20 20:31:38 +01:00
boot Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-01-09 12:13:43 -08:00
cavium-octeon remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
cobalt
configs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2019-12-01 13:26:18 -08:00
crypto crypto: {arm,arm64,mips}/poly1305 - remove redundant non-reduction from emit 2020-01-16 15:18:12 +08:00
dec
emma
fw A few MIPS fixes: 2019-11-01 14:36:44 -07:00
generic remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
include SCSI misc on 20200129 2020-01-29 18:16:16 -08:00
jazz dma-mapping: drop the dev argument to arch_sync_dma_for_* 2019-11-20 20:31:38 +01:00
jz4740 Merge branch 'ingenic-tcu-v5.4' into mips-next 2019-08-08 15:33:16 -07:00
kernel threads-v5.6 2020-01-29 19:38:34 -08:00
kvm mips: add support for folded p4d page tables 2019-11-22 10:51:22 -08:00
lantiq remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
lasat treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 182 2019-05-30 11:29:20 -07:00
lib MIPS: Loongson64: Rename CPU TYPES 2019-10-31 15:03:10 -07:00
loongson2ef remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
loongson32 remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
loongson64 remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
math-emu MIPS: math-emu: Reuse name array in debugfs_fpuemu() 2019-11-11 10:56:14 -08:00
mm dma-mapping updates for 5.5-rc1 2019-11-28 11:16:43 -08:00
mti-malta remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
net A collection of MIPS fixes: 2020-01-04 14:16:57 -08:00
netlogic MIPS: xlp: Drop boot_mem_map 2019-08-23 14:47:21 +01:00
oprofile MIPS: Loongson: Rename LOONGSON1 to LOONGSON32 2019-11-11 10:43:13 -08:00
paravirt
pci remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
pic32 remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
pistachio A batch of MIPS fixes: 2019-06-08 13:09:31 -07:00
pmcs-msp71xx remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
pnx833x A batch of MIPS fixes: 2019-06-08 13:09:31 -07:00
power mips: check for dsp presence only once before save/restore 2019-10-07 10:58:53 -07:00
ralink remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
rb532 remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
sgi-ip22 MIPS: SGI-IP22/28: Use PROM for memory detection 2019-10-09 14:55:57 -07:00
sgi-ip27 The main MIPS changes for 5.5: 2019-11-25 17:42:56 -08:00
sgi-ip30 MIPS: add support for SGI Octane (IP30) 2019-11-01 14:58:56 -07:00
sgi-ip32 rtc: ds1685: add indirect access method and remove plat_read/plat_write 2019-10-16 10:39:00 +02:00
sibyte
sni remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
tools MIPS: Check Loongson3 LL/SC errata workaround correctness 2019-10-07 09:43:13 -07:00
txx9 A batch of MIPS fixes: 2019-06-08 13:09:31 -07:00
vdso MIPS: vdso: Define BUILD_VDSO32 when building a 32bit kernel 2020-01-16 21:24:25 +01:00
vr41xx
Kbuild treewide: Add SPDX license identifier - Kbuild 2019-05-30 11:32:33 -07:00
Kbuild.platforms MIPS: add support for SGI Octane (IP30) 2019-11-01 14:58:56 -07:00
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.debug MIPS: cmdline: Remove redundant Kconfig defaults 2019-10-09 15:53:16 -07:00
Makefile Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2019-11-25 19:49:58 -08:00
Makefile.postlink MIPS: Check Loongson3 LL/SC errata workaround correctness 2019-10-07 09:43:13 -07:00