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54 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Wang Haojun
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b3ff2881ba |
MIPS: syscalls: Wire up futex_waitv syscall
Wire up the futex_waitv syscall. Fix Build warning: #warning syscall futex_waitv not implemented [-Wcpp] Signed-off-by: Wang Haojun <wanghaojun@loongson.cn> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> |
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Arnd Bergmann
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59ab844eed |
compat: remove some compat entry points
These are all handled correctly when calling the native system call entry point, so remove the special cases. Link: https://lkml.kernel.org/r/20210727144859.4150043-6-arnd@kernel.org Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Feng Tang <feng.tang@intel.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Linus Torvalds
|
14726903c8 |
Merge branch 'akpm' (patches from Andrew)
Merge misc updates from Andrew Morton: "173 patches. Subsystems affected by this series: ia64, ocfs2, block, and mm (debug, pagecache, gup, swap, shmem, memcg, selftests, pagemap, mremap, bootmem, sparsemem, vmalloc, kasan, pagealloc, memory-failure, hugetlb, userfaultfd, vmscan, compaction, mempolicy, memblock, oom-kill, migration, ksm, percpu, vmstat, and madvise)" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (173 commits) mm/madvise: add MADV_WILLNEED to process_madvise() mm/vmstat: remove unneeded return value mm/vmstat: simplify the array size calculation mm/vmstat: correct some wrong comments mm/percpu,c: remove obsolete comments of pcpu_chunk_populated() selftests: vm: add COW time test for KSM pages selftests: vm: add KSM merging time test mm: KSM: fix data type selftests: vm: add KSM merging across nodes test selftests: vm: add KSM zero page merging test selftests: vm: add KSM unmerge test selftests: vm: add KSM merge test mm/migrate: correct kernel-doc notation mm: wire up syscall process_mrelease mm: introduce process_mrelease system call memblock: make memblock_find_in_range method private mm/mempolicy.c: use in_task() in mempolicy_slab_node() mm/mempolicy: unify the create() func for bind/interleave/prefer-many policies mm/mempolicy: advertise new MPOL_PREFERRED_MANY mm/hugetlb: add support for mempolicy MPOL_PREFERRED_MANY ... |
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Suren Baghdasaryan
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dce4910396 |
mm: wire up syscall process_mrelease
Split off from prev patch in the series that implements the syscall. Link: https://lkml.kernel.org/r/20210809185259.405936-2-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Christian Brauner <christian.brauner@ubuntu.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Florian Weimer <fweimer@redhat.com> Cc: Jan Engelhardt <jengelh@inai.de> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Roman Gushchin <guro@fb.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Tim Murray <timmurray@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Eric W. Biederman
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b48c7236b1 |
exit/bdflush: Remove the deprecated bdflush system call
The bdflush system call has been deprecated for a very long time. Recently Michael Schmitz tested[1] and found that the last known caller of of the bdflush system call is unaffected by it's removal. Since the code is not needed delete it. [1] https://lkml.kernel.org/r/36123b5d-daa0-6c2b-f2d4-a942f069fd54@gmail.com Link: https://lkml.kernel.org/r/87sg10quue.fsf_-_@disp2133 Tested-by: Michael Schmitz <schmitzmic@gmail.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Cyril Hrubis <chrubis@suse.cz> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
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Linus Torvalds
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19b4385922 |
Merge tag 'mips_5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux
Pull MIPS updates from Thomas Bogendoerfer: - add support for OpeneEmbed SOM9331 board - Ingenic fixes/improvments - other fixes and cleanups * tag 'mips_5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux: (39 commits) MIPS: Fix PKMAP with 32-bit MIPS huge page support MIPS: CI20: Add second percpu timer for SMP. MIPS: CI20: Reduce clocksource to 750 kHz. MIPS: Ingenic: Add MAC syscon nodes for Ingenic SoCs. dt-bindings: clock: Add documentation for MAC PHY control bindings. MIPS: X1830: Respect cell count of common properties. MIPS: set mips32r5 for virt extensions MIPS: loongsoon64: Reserve memory below starting pfn to prevent Oops MIPS: MT extensions are not available on MIPS32r1 mips/kvm: Use BUG_ON instead of if condition followed by BUG MIPS: OCTEON: octeon-usb: Use devm_platform_get_and_ioremap_resource() MIPS: add PMD table accounting into MIPS'pmd_alloc_one MIPS: Loongson64: fix spelling of SPDX tag MIPS: ingenic: rs90: Add dedicated VRAM memory region MIPS: ingenic: gcw0: Set codec to cap-less mode for FM radio MIPS: ingenic: jz4780: Fix I2C nodes to match DT doc MIPS: ingenic: Select CPU_SUPPORTS_CPUFREQ && MIPS_EXTERNAL_TIMER MIPS: Kconfig: ingenic: Ensure MACH_INGENIC_GENERIC selects all SoCs MIPS: cpu-probe: Fix FPU detection on Ingenic JZ4760(B) MIPS: boot: Support specifying UART port on Ingenic SoCs ... |
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Jan Kara
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65ffb3d69e |
quota: Wire up quotactl_fd syscall
Wire up the quotactl_fd syscall. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> |
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Masahiro Yamada
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c8ba52d1b7 |
mips: syscalls: use pattern rules to generate syscall headers
Use pattern rules to unify similar build rules among n32, n64, and o32. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> |
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Masahiro Yamada
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faf243ede9 |
mips: syscalls: define syscall offsets directly in <asm/unistd.h>
There is no good reason to generate the syscall offset macros by scripting since they are not derived from the syscall tables. Define __NR_*_Linux macros directly in arch/mips/include/asm/unistd.h, and clean up the Makefile and the shell script. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> |
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Jan Kara
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5b9fedb31e |
quota: Disable quotactl_path syscall
In commit
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Linus Torvalds
|
17ae69aba8 |
Merge tag 'landlock_v34' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull Landlock LSM from James Morris:
"Add Landlock, a new LSM from Mickaël Salaün.
Briefly, Landlock provides for unprivileged application sandboxing.
From Mickaël's cover letter:
"The goal of Landlock is to enable to restrict ambient rights (e.g.
global filesystem access) for a set of processes. Because Landlock
is a stackable LSM [1], it makes possible to create safe security
sandboxes as new security layers in addition to the existing
system-wide access-controls. This kind of sandbox is expected to
help mitigate the security impact of bugs or unexpected/malicious
behaviors in user-space applications. Landlock empowers any
process, including unprivileged ones, to securely restrict
themselves.
Landlock is inspired by seccomp-bpf but instead of filtering
syscalls and their raw arguments, a Landlock rule can restrict the
use of kernel objects like file hierarchies, according to the
kernel semantic. Landlock also takes inspiration from other OS
sandbox mechanisms: XNU Sandbox, FreeBSD Capsicum or OpenBSD
Pledge/Unveil.
In this current form, Landlock misses some access-control features.
This enables to minimize this patch series and ease review. This
series still addresses multiple use cases, especially with the
combined use of seccomp-bpf: applications with built-in sandboxing,
init systems, security sandbox tools and security-oriented APIs [2]"
The cover letter and v34 posting is here:
https://lore.kernel.org/linux-security-module/20210422154123.13086-1-mic@digikod.net/
See also:
https://landlock.io/
This code has had extensive design discussion and review over several
years"
Link: https://lore.kernel.org/lkml/50db058a-7dde-441b-a7f9-f6837fe8b69f@schaufler-ca.com/ [1]
Link: https://lore.kernel.org/lkml/f646e1c7-33cf-333f-070c-0a40ad0468cd@digikod.net/ [2]
* tag 'landlock_v34' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
landlock: Enable user space to infer supported features
landlock: Add user and kernel documentation
samples/landlock: Add a sandbox manager example
selftests/landlock: Add user space tests
landlock: Add syscall implementations
arch: Wire up Landlock syscalls
fs,security: Add sb_delete hook
landlock: Support filesystem access-control
LSM: Infrastructure management of the superblock
landlock: Add ptrace restrictions
landlock: Set up the security framework and manage credentials
landlock: Add ruleset and domain management
landlock: Add object management
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Linus Torvalds
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77d51337d6 |
Merge tag 'mips_5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux
Pull MIPS updates from Thomas Bogendoerfer: - removed get_fs/set_fs - removed broken/unmaintained MIPS KVM trap and emulate support - added support for Loongson-2K1000 - fixes and cleanups * tag 'mips_5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux: (107 commits) MIPS: BCM63XX: Use BUG_ON instead of condition followed by BUG. MIPS: select ARCH_KEEP_MEMBLOCK unconditionally mips: Do not include hi and lo in clobber list for R6 MIPS:DTS:Correct the license for Loongson-2K MIPS:DTS:Fix label name and interrupt number of ohci for Loongson-2K MIPS: Avoid handcoded DIVU in `__div64_32' altogether lib/math/test_div64: Correct the spelling of "dividend" lib/math/test_div64: Fix error message formatting mips/bootinfo:correct some comments of fw_arg MIPS: Avoid DIVU in `__div64_32' is result would be zero MIPS: Reinstate platform `__div64_32' handler div64: Correct inline documentation for `do_div' lib/math: Add a `do_div' test module MIPS: Makefile: Replace -pg with CC_FLAGS_FTRACE MIPS: pci-legacy: revert "use generic pci_enable_resources" MIPS: Loongson64: Add kexec/kdump support MIPS: pci-legacy: use generic pci_enable_resources MIPS: pci-legacy: remove busn_resource field MIPS: pci-legacy: remove redundant info messages MIPS: pci-legacy: stop using of_pci_range_to_resource ... |
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Mickaël Salaün
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a49f4f81cb |
arch: Wire up Landlock syscalls
Wire up the following system calls for all architectures: * landlock_create_ruleset(2) * landlock_add_rule(2) * landlock_restrict_self(2) Cc: Arnd Bergmann <arnd@arndb.de> Cc: James Morris <jmorris@namei.org> Cc: Jann Horn <jannh@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Serge E. Hallyn <serge@hallyn.com> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Link: https://lore.kernel.org/r/20210422154123.13086-10-mic@digikod.net Signed-off-by: James Morris <jamorris@linux.microsoft.com> |
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Sascha Hauer
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fa8b90070a |
quota: wire up quotactl_path
Wire up the quotactl_path syscall added in the previous patch. Link: https://lore.kernel.org/r/20210304123541.30749-3-s.hauer@pengutronix.de Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> |
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Masahiro Yamada
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6228bd6528 |
mips: syscalls: switch to generic syscallhdr.sh
Many architectures duplicate similar shell scripts. This commit converts mips to use scripts/syscallhdr.sh. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> |
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Masahiro Yamada
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ecbba30fbf |
mips: syscalls: switch to generic syscalltbl.sh
Many architectures duplicate similar shell scripts. This commit converts mips to use scripts/syscalltbl.sh. This also unifies syscall_table_32_o32.h and syscall_table_64_o32.h into syscall_table_o32.h. The offset parameters are unneeded here; __SYSCALL(nr, entry) is defined as 'PTR entry', so the parameter 'nr' is not used in the first place. With this commit, syscall tables and generated files are straight mapped, which makes things easier to understand. syscall_n32.tbl --> syscall_table_n32.h syscall_n64.tbl --> syscall_table_n64.h syscall_o32.tbl --> syscall_table_o32.h Then, the abi parameters are also unneeded. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> |
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Linus Torvalds
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6fbd6cf85a |
Merge tag 'kbuild-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Fix false-positive build warnings for ARCH=ia64 builds
- Optimize dictionary size for module compression with xz
- Check the compiler and linker versions in Kconfig
- Fix misuse of extra-y
- Support DWARF v5 debug info
- Clamp SUBLEVEL to 255 because stable releases 4.4.x and 4.9.x
exceeded the limit
- Add generic syscall{tbl,hdr}.sh for cleanups across arches
- Minor cleanups of genksyms
- Minor cleanups of Kconfig
* tag 'kbuild-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (38 commits)
initramfs: Remove redundant dependency of RD_ZSTD on BLK_DEV_INITRD
kbuild: remove deprecated 'always' and 'hostprogs-y/m'
kbuild: parse C= and M= before changing the working directory
kbuild: reuse this-makefile to define abs_srctree
kconfig: unify rule of config, menuconfig, nconfig, gconfig, xconfig
kconfig: omit --oldaskconfig option for 'make config'
kconfig: fix 'invalid option' for help option
kconfig: remove dead code in conf_askvalue()
kconfig: clean up nested if-conditionals in check_conf()
kconfig: Remove duplicate call to sym_get_string_value()
Makefile: Remove # characters from compiler string
Makefile: reuse CC_VERSION_TEXT
kbuild: check the minimum linker version in Kconfig
kbuild: remove ld-version macro
scripts: add generic syscallhdr.sh
scripts: add generic syscalltbl.sh
arch: syscalls: remove $(srctree)/ prefix from syscall tables
arch: syscalls: add missing FORCE and fix 'targets' to make if_changed work
gen_compile_commands: prune some directories
kbuild: simplify access to the kernel's version
...
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Linus Torvalds
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7d6beb71da |
Merge tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull idmapped mounts from Christian Brauner:
"This introduces idmapped mounts which has been in the making for some
time. Simply put, different mounts can expose the same file or
directory with different ownership. This initial implementation comes
with ports for fat, ext4 and with Christoph's port for xfs with more
filesystems being actively worked on by independent people and
maintainers.
Idmapping mounts handle a wide range of long standing use-cases. Here
are just a few:
- Idmapped mounts make it possible to easily share files between
multiple users or multiple machines especially in complex
scenarios. For example, idmapped mounts will be used in the
implementation of portable home directories in
systemd-homed.service(8) where they allow users to move their home
directory to an external storage device and use it on multiple
computers where they are assigned different uids and gids. This
effectively makes it possible to assign random uids and gids at
login time.
- It is possible to share files from the host with unprivileged
containers without having to change ownership permanently through
chown(2).
- It is possible to idmap a container's rootfs and without having to
mangle every file. For example, Chromebooks use it to share the
user's Download folder with their unprivileged containers in their
Linux subsystem.
- It is possible to share files between containers with
non-overlapping idmappings.
- Filesystem that lack a proper concept of ownership such as fat can
use idmapped mounts to implement discretionary access (DAC)
permission checking.
- They allow users to efficiently changing ownership on a per-mount
basis without having to (recursively) chown(2) all files. In
contrast to chown (2) changing ownership of large sets of files is
instantenous with idmapped mounts. This is especially useful when
ownership of a whole root filesystem of a virtual machine or
container is changed. With idmapped mounts a single syscall
mount_setattr syscall will be sufficient to change the ownership of
all files.
- Idmapped mounts always take the current ownership into account as
idmappings specify what a given uid or gid is supposed to be mapped
to. This contrasts with the chown(2) syscall which cannot by itself
take the current ownership of the files it changes into account. It
simply changes the ownership to the specified uid and gid. This is
especially problematic when recursively chown(2)ing a large set of
files which is commong with the aforementioned portable home
directory and container and vm scenario.
- Idmapped mounts allow to change ownership locally, restricting it
to specific mounts, and temporarily as the ownership changes only
apply as long as the mount exists.
Several userspace projects have either already put up patches and
pull-requests for this feature or will do so should you decide to pull
this:
- systemd: In a wide variety of scenarios but especially right away
in their implementation of portable home directories.
https://systemd.io/HOME_DIRECTORY/
- container runtimes: containerd, runC, LXD:To share data between
host and unprivileged containers, unprivileged and privileged
containers, etc. The pull request for idmapped mounts support in
containerd, the default Kubernetes runtime is already up for quite
a while now: https://github.com/containerd/containerd/pull/4734
- The virtio-fs developers and several users have expressed interest
in using this feature with virtual machines once virtio-fs is
ported.
- ChromeOS: Sharing host-directories with unprivileged containers.
I've tightly synced with all those projects and all of those listed
here have also expressed their need/desire for this feature on the
mailing list. For more info on how people use this there's a bunch of
talks about this too. Here's just two recent ones:
https://www.cncf.io/wp-content/uploads/2020/12/Rootless-Containers-in-Gitpod.pdf
https://fosdem.org/2021/schedule/event/containers_idmap/
This comes with an extensive xfstests suite covering both ext4 and
xfs:
https://git.kernel.org/brauner/xfstests-dev/h/idmapped_mounts
It covers truncation, creation, opening, xattrs, vfscaps, setid
execution, setgid inheritance and more both with idmapped and
non-idmapped mounts. It already helped to discover an unrelated xfs
setgid inheritance bug which has since been fixed in mainline. It will
be sent for inclusion with the xfstests project should you decide to
merge this.
In order to support per-mount idmappings vfsmounts are marked with
user namespaces. The idmapping of the user namespace will be used to
map the ids of vfs objects when they are accessed through that mount.
By default all vfsmounts are marked with the initial user namespace.
The initial user namespace is used to indicate that a mount is not
idmapped. All operations behave as before and this is verified in the
testsuite.
Based on prior discussions we want to attach the whole user namespace
and not just a dedicated idmapping struct. This allows us to reuse all
the helpers that already exist for dealing with idmappings instead of
introducing a whole new range of helpers. In addition, if we decide in
the future that we are confident enough to enable unprivileged users
to setup idmapped mounts the permission checking can take into account
whether the caller is privileged in the user namespace the mount is
currently marked with.
The user namespace the mount will be marked with can be specified by
passing a file descriptor refering to the user namespace as an
argument to the new mount_setattr() syscall together with the new
MOUNT_ATTR_IDMAP flag. The system call follows the openat2() pattern
of extensibility.
The following conditions must be met in order to create an idmapped
mount:
- The caller must currently have the CAP_SYS_ADMIN capability in the
user namespace the underlying filesystem has been mounted in.
- The underlying filesystem must support idmapped mounts.
- The mount must not already be idmapped. This also implies that the
idmapping of a mount cannot be altered once it has been idmapped.
- The mount must be a detached/anonymous mount, i.e. it must have
been created by calling open_tree() with the OPEN_TREE_CLONE flag
and it must not already have been visible in the filesystem.
The last two points guarantee easier semantics for userspace and the
kernel and make the implementation significantly simpler.
By default vfsmounts are marked with the initial user namespace and no
behavioral or performance changes are observed.
The manpage with a detailed description can be found here:
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Masahiro Yamada
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29c5c3ac63 |
arch: syscalls: remove $(srctree)/ prefix from syscall tables
The 'syscall' variables are not directly used in the commands. Remove the $(srctree)/ prefix because we can rely on VPATH. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> |
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Masahiro Yamada
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865fa29f7d |
arch: syscalls: add missing FORCE and fix 'targets' to make if_changed work
The rules in these Makefiles cannot detect the command line change because the prerequisite 'FORCE' is missing. Adding 'FORCE' will result in the headers being rebuilt every time because the 'targets' additions are also wrong; the file paths in 'targets' must be relative to the current Makefile. Fix all of them so the if_changed rules work correctly. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> |
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Christian Brauner
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2a1867219c |
fs: add mount_setattr()
This implements the missing mount_setattr() syscall. While the new mount
api allows to change the properties of a superblock there is currently
no way to change the properties of a mount or a mount tree using file
descriptors which the new mount api is based on. In addition the old
mount api has the restriction that mount options cannot be applied
recursively. This hasn't changed since changing mount options on a
per-mount basis was implemented in [1] and has been a frequent request
not just for convenience but also for security reasons. The legacy
mount syscall is unable to accommodate this behavior without introducing
a whole new set of flags because MS_REC | MS_REMOUNT | MS_BIND |
MS_RDONLY | MS_NOEXEC | [...] only apply the mount option to the topmost
mount. Changing MS_REC to apply to the whole mount tree would mean
introducing a significant uapi change and would likely cause significant
regressions.
The new mount_setattr() syscall allows to recursively clear and set
mount options in one shot. Multiple calls to change mount options
requesting the same changes are idempotent:
int mount_setattr(int dfd, const char *path, unsigned flags,
struct mount_attr *uattr, size_t usize);
Flags to modify path resolution behavior are specified in the @flags
argument. Currently, AT_EMPTY_PATH, AT_RECURSIVE, AT_SYMLINK_NOFOLLOW,
and AT_NO_AUTOMOUNT are supported. If useful, additional lookup flags to
restrict path resolution as introduced with openat2() might be supported
in the future.
The mount_setattr() syscall can be expected to grow over time and is
designed with extensibility in mind. It follows the extensible syscall
pattern we have used with other syscalls such as openat2(), clone3(),
sched_{set,get}attr(), and others.
The set of mount options is passed in the uapi struct mount_attr which
currently has the following layout:
struct mount_attr {
__u64 attr_set;
__u64 attr_clr;
__u64 propagation;
__u64 userns_fd;
};
The @attr_set and @attr_clr members are used to clear and set mount
options. This way a user can e.g. request that a set of flags is to be
raised such as turning mounts readonly by raising MOUNT_ATTR_RDONLY in
@attr_set while at the same time requesting that another set of flags is
to be lowered such as removing noexec from a mount tree by specifying
MOUNT_ATTR_NOEXEC in @attr_clr.
Note, since the MOUNT_ATTR_<atime> values are an enum starting from 0,
not a bitmap, users wanting to transition to a different atime setting
cannot simply specify the atime setting in @attr_set, but must also
specify MOUNT_ATTR__ATIME in the @attr_clr field. So we ensure that
MOUNT_ATTR__ATIME can't be partially set in @attr_clr and that @attr_set
can't have any atime bits set if MOUNT_ATTR__ATIME isn't set in
@attr_clr.
The @propagation field lets callers specify the propagation type of a
mount tree. Propagation is a single property that has four different
settings and as such is not really a flag argument but an enum.
Specifically, it would be unclear what setting and clearing propagation
settings in combination would amount to. The legacy mount() syscall thus
forbids the combination of multiple propagation settings too. The goal
is to keep the semantics of mount propagation somewhat simple as they
are overly complex as it is.
The @userns_fd field lets user specify a user namespace whose idmapping
becomes the idmapping of the mount. This is implemented and explained in
detail in the next patch.
[1]: commit
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Alexander Lobakin
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ccb2177486 |
MIPS: UAPI: unexport unistd_nr_{n32,n64,o32}.h
unistd_nr_{n32,n64,o32}.h are needed only by include/asm/unistd.h,
which is a kernel-side header file, and their contents is generally
not for userland use.
Move their target destination from include/generated/uapi/asm/ to
include/generated/asm/ to disable exporting them as UAPI headers.
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
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Heiko Carstens
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450f68e242 |
epoll: fix compat syscall wire up of epoll_pwait2
Commit |
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Willem de Bruijn
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b0a0c2615f |
epoll: wire up syscall epoll_pwait2
Split off from prev patch in the series that implements the syscall. Link: https://lkml.kernel.org/r/20201121144401.3727659-4-willemdebruijn.kernel@gmail.com Signed-off-by: Willem de Bruijn <willemb@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Minchan Kim
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ecb8ac8b1f |
mm/madvise: introduce process_madvise() syscall: an external memory hinting API
There is usecase that System Management Software(SMS) want to give a
memory hint like MADV_[COLD|PAGEEOUT] to other processes and in the
case of Android, it is the ActivityManagerService.
The information required to make the reclaim decision is not known to the
app. Instead, it is known to the centralized userspace
daemon(ActivityManagerService), and that daemon must be able to initiate
reclaim on its own without any app involvement.
To solve the issue, this patch introduces a new syscall
process_madvise(2). It uses pidfd of an external process to give the
hint. It also supports vector address range because Android app has
thousands of vmas due to zygote so it's totally waste of CPU and power if
we should call the syscall one by one for each vma.(With testing 2000-vma
syscall vs 1-vector syscall, it showed 15% performance improvement. I
think it would be bigger in real practice because the testing ran very
cache friendly environment).
Another potential use case for the vector range is to amortize the cost
ofTLB shootdowns for multiple ranges when using MADV_DONTNEED; this could
benefit users like TCP receive zerocopy and malloc implementations. In
future, we could find more usecases for other advises so let's make it
happens as API since we introduce a new syscall at this moment. With
that, existing madvise(2) user could replace it with process_madvise(2)
with their own pid if they want to have batch address ranges support
feature.
ince it could affect other process's address range, only privileged
process(PTRACE_MODE_ATTACH_FSCREDS) or something else(e.g., being the same
UID) gives it the right to ptrace the process could use it successfully.
The flag argument is reserved for future use if we need to extend the API.
I think supporting all hints madvise has/will supported/support to
process_madvise is rather risky. Because we are not sure all hints make
sense from external process and implementation for the hint may rely on
the caller being in the current context so it could be error-prone. Thus,
I just limited hints as MADV_[COLD|PAGEOUT] in this patch.
If someone want to add other hints, we could hear the usecase and review
it for each hint. It's safer for maintenance rather than introducing a
buggy syscall but hard to fix it later.
So finally, the API is as follows,
ssize_t process_madvise(int pidfd, const struct iovec *iovec,
unsigned long vlen, int advice, unsigned int flags);
DESCRIPTION
The process_madvise() system call is used to give advice or directions
to the kernel about the address ranges from external process as well as
local process. It provides the advice to address ranges of process
described by iovec and vlen. The goal of such advice is to improve
system or application performance.
The pidfd selects the process referred to by the PID file descriptor
specified in pidfd. (See pidofd_open(2) for further information)
The pointer iovec points to an array of iovec structures, defined in
<sys/uio.h> as:
struct iovec {
void *iov_base; /* starting address */
size_t iov_len; /* number of bytes to be advised */
};
The iovec describes address ranges beginning at address(iov_base)
and with size length of bytes(iov_len).
The vlen represents the number of elements in iovec.
The advice is indicated in the advice argument, which is one of the
following at this moment if the target process specified by pidfd is
external.
MADV_COLD
MADV_PAGEOUT
Permission to provide a hint to external process is governed by a
ptrace access mode PTRACE_MODE_ATTACH_FSCREDS check; see ptrace(2).
The process_madvise supports every advice madvise(2) has if target
process is in same thread group with calling process so user could
use process_madvise(2) to extend existing madvise(2) to support
vector address ranges.
RETURN VALUE
On success, process_madvise() returns the number of bytes advised.
This return value may be less than the total number of requested
bytes, if an error occurred. The caller should check return value
to determine whether a partial advice occurred.
FAQ:
Q.1 - Why does any external entity have better knowledge?
Quote from Sandeep
"For Android, every application (including the special SystemServer)
are forked from Zygote. The reason of course is to share as many
libraries and classes between the two as possible to benefit from the
preloading during boot.
After applications start, (almost) all of the APIs end up calling into
this SystemServer process over IPC (binder) and back to the
application.
In a fully running system, the SystemServer monitors every single
process periodically to calculate their PSS / RSS and also decides
which process is "important" to the user for interactivity.
So, because of how these processes start _and_ the fact that the
SystemServer is looping to monitor each process, it does tend to *know*
which address range of the application is not used / useful.
Besides, we can never rely on applications to clean things up
themselves. We've had the "hey app1, the system is low on memory,
please trim your memory usage down" notifications for a long time[1].
They rely on applications honoring the broadcasts and very few do.
So, if we want to avoid the inevitable killing of the application and
restarting it, some way to be able to tell the OS about unimportant
memory in these applications will be useful.
- ssp
Q.2 - How to guarantee the race(i.e., object validation) between when
giving a hint from an external process and get the hint from the target
process?
process_madvise operates on the target process's address space as it
exists at the instant that process_madvise is called. If the space
target process can run between the time the process_madvise process
inspects the target process address space and the time that
process_madvise is actually called, process_madvise may operate on
memory regions that the calling process does not expect. It's the
responsibility of the process calling process_madvise to close this
race condition. For example, the calling process can suspend the
target process with ptrace, SIGSTOP, or the freezer cgroup so that it
doesn't have an opportunity to change its own address space before
process_madvise is called. Another option is to operate on memory
regions that the caller knows a priori will be unchanged in the target
process. Yet another option is to accept the race for certain
process_madvise calls after reasoning that mistargeting will do no
harm. The suggested API itself does not provide synchronization. It
also apply other APIs like move_pages, process_vm_write.
The race isn't really a problem though. Why is it so wrong to require
that callers do their own synchronization in some manner? Nobody
objects to write(2) merely because it's possible for two processes to
open the same file and clobber each other's writes --- instead, we tell
people to use flock or something. Think about mmap. It never
guarantees newly allocated address space is still valid when the user
tries to access it because other threads could unmap the memory right
before. That's where we need synchronization by using other API or
design from userside. It shouldn't be part of API itself. If someone
needs more fine-grained synchronization rather than process level,
there were two ideas suggested - cookie[2] and anon-fd[3]. Both are
applicable via using last reserved argument of the API but I don't
think it's necessary right now since we have already ways to prevent
the race so don't want to add additional complexity with more
fine-grained optimization model.
To make the API extend, it reserved an unsigned long as last argument
so we could support it in future if someone really needs it.
Q.3 - Why doesn't ptrace work?
Injecting an madvise in the target process using ptrace would not work
for us because such injected madvise would have to be executed by the
target process, which means that process would have to be runnable and
that creates the risk of the abovementioned race and hinting a wrong
VMA. Furthermore, we want to act the hint in caller's context, not the
callee's, because the callee is usually limited in cpuset/cgroups or
even freezed state so they can't act by themselves quick enough, which
causes more thrashing/kill. It doesn't work if the target process are
ptraced(e.g., strace, debugger, minidump) because a process can have at
most one ptracer.
[1] https://developer.android.com/topic/performance/memory"
[2] process_getinfo for getting the cookie which is updated whenever
vma of process address layout are changed - Daniel Colascione -
https://lore.kernel.org/lkml/20190520035254.57579-1-minchan@kernel.org/T/#m7694416fd179b2066a2c62b5b139b14e3894e224
[3] anonymous fd which is used for the object(i.e., address range)
validation - Michal Hocko -
https://lore.kernel.org/lkml/20200120112722.GY18451@dhcp22.suse.cz/
[minchan@kernel.org: fix process_madvise build break for arm64]
Link: http://lkml.kernel.org/r/20200303145756.GA219683@google.com
[minchan@kernel.org: fix build error for mips of process_madvise]
Link: http://lkml.kernel.org/r/20200508052517.GA197378@google.com
[akpm@linux-foundation.org: fix patch ordering issue]
[akpm@linux-foundation.org: fix arm64 whoops]
[minchan@kernel.org: make process_madvise() vlen arg have type size_t, per Florian]
[akpm@linux-foundation.org: fix i386 build]
[sfr@canb.auug.org.au: fix syscall numbering]
Link: https://lkml.kernel.org/r/20200905142639.49fc3f1a@canb.auug.org.au
[sfr@canb.auug.org.au: madvise.c needs compat.h]
Link: https://lkml.kernel.org/r/20200908204547.285646b4@canb.auug.org.au
[minchan@kernel.org: fix mips build]
Link: https://lkml.kernel.org/r/20200909173655.GC2435453@google.com
[yuehaibing@huawei.com: remove duplicate header which is included twice]
Link: https://lkml.kernel.org/r/20200915121550.30584-1-yuehaibing@huawei.com
[minchan@kernel.org: do not use helper functions for process_madvise]
Link: https://lkml.kernel.org/r/20200921175539.GB387368@google.com
[akpm@linux-foundation.org: pidfd_get_pid() gained an argument]
[sfr@canb.auug.org.au: fix up for "iov_iter: transparently handle compat iovecs in import_iovec"]
Link: https://lkml.kernel.org/r/20200928212542.468e1fef@canb.auug.org.au
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Christian Brauner <christian@brauner.io>
Cc: Daniel Colascione <dancol@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Dias <joaodias@google.com>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oleksandr Natalenko <oleksandr@redhat.com>
Cc: Sandeep Patil <sspatil@google.com>
Cc: SeongJae Park <sj38.park@gmail.com>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Sonny Rao <sonnyrao@google.com>
Cc: Tim Murray <timmurray@google.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Florian Weimer <fw@deneb.enyo.de>
Cc: <linux-man@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200302193630.68771-3-minchan@kernel.org
Link: http://lkml.kernel.org/r/20200508183320.GA125527@google.com
Link: http://lkml.kernel.org/r/20200622192900.22757-4-minchan@kernel.org
Link: https://lkml.kernel.org/r/20200901000633.1920247-4-minchan@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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