Commit Graph

22154 Commits

Author SHA1 Message Date
Jann Horn 378c6520e7 fs/coredump: prevent fsuid=0 dumps into user-controlled directories
This commit fixes the following security hole affecting systems where
all of the following conditions are fulfilled:

 - The fs.suid_dumpable sysctl is set to 2.
 - The kernel.core_pattern sysctl's value starts with "/". (Systems
   where kernel.core_pattern starts with "|/" are not affected.)
 - Unprivileged user namespace creation is permitted. (This is
   true on Linux >=3.8, but some distributions disallow it by
   default using a distro patch.)

Under these conditions, if a program executes under secure exec rules,
causing it to run with the SUID_DUMP_ROOT flag, then unshares its user
namespace, changes its root directory and crashes, the coredump will be
written using fsuid=0 and a path derived from kernel.core_pattern - but
this path is interpreted relative to the root directory of the process,
allowing the attacker to control where a coredump will be written with
root privileges.

To fix the security issue, always interpret core_pattern for dumps that
are written under SUID_DUMP_ROOT relative to the root directory of init.

Signed-off-by: Jann Horn <jann@thejh.net>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22 15:36:02 -07:00
Oleg Nesterov 1333ab0315 ptrace: change __ptrace_unlink() to clear ->ptrace under ->siglock
This test-case (simplified version of generated by syzkaller)

	#include <unistd.h>
	#include <sys/ptrace.h>
	#include <sys/wait.h>

	void test(void)
	{
		for (;;) {
			if (fork()) {
				wait(NULL);
				continue;
			}

			ptrace(PTRACE_SEIZE, getppid(), 0, 0);
			ptrace(PTRACE_INTERRUPT, getppid(), 0, 0);
			_exit(0);
		}
	}

	int main(void)
	{
		int np;

		for (np = 0; np < 8; ++np)
			if (!fork())
				test();

		while (wait(NULL) > 0)
			;
		return 0;
	}

triggers the 2nd WARN_ON_ONCE(!signr) warning in do_jobctl_trap().  The
problem is that __ptrace_unlink() clears task->jobctl under siglock but
task->ptrace is cleared without this lock held; this fools the "else"
branch which assumes that !PT_SEIZED means PT_PTRACED.

Note also that most of other PTRACE_SEIZE checks can race with detach
from the exiting tracer too.  Say, the callers of ptrace_trap_notify()
assume that SEIZED can't go away after it was checked.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22 15:36:02 -07:00
Andy Lutomirski efbc0fbf34 auditsc: for seccomp events, log syscall compat state using in_compat_syscall
Except on SPARC, this is what the code always did.  SPARC compat seccomp
was buggy, although the impact of the bug was limited because SPARC
32-bit and 64-bit syscall numbers are the same.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22 15:36:02 -07:00
Andy Lutomirski 5c465217a9 ptrace: in PEEK_SIGINFO, check syscall bitness, not task bitness
Users of the 32-bit ptrace() ABI expect the full 32-bit ABI.  siginfo
translation should check ptrace() ABI, not caller task ABI.

This is an ABI change on SPARC.  Let's hope that no one relied on the
old buggy ABI.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22 15:36:02 -07:00
Andy Lutomirski 5c38065e02 seccomp: check in_compat_syscall, not is_compat_task, in strict mode
Seccomp wants to know the syscall bitness, not the caller task bitness,
when it selects the syscall whitelist.

As far as I know, this makes no difference on any architecture, so it's
not a security problem.  (It generates identical code everywhere except
sparc, and, on sparc, the syscall numbering is the same for both ABIs.)

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22 15:36:02 -07:00
Tetsuo Handa b4aa14a63c kernel/hung_task.c: use timeout diff when timeout is updated
When new timeout is written to /proc/sys/kernel/hung_task_timeout_secs,
khungtaskd is interrupted and again sleeps for full timeout duration.

This means that hang task will not be checked if new timeout is written
periodically within old timeout duration and/or checking of hang task
will be delayed for up to previous timeout duration.  Fix this by
remembering last time khungtaskd checked hang task.

This change will allow other watchdog tasks (if any) to share khungtaskd
by sleeping for minimal timeout diff of all watchdog tasks.  Doing more
watchdog tasks from khungtaskd will reduce the possibility of printk()
collisions by multiple watchdog threads.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22 15:36:02 -07:00
Linus Torvalds 5518f66b5a Merge branch 'for-4.6-ns' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup namespace support from Tejun Heo:
 "These are changes to implement namespace support for cgroup which has
  been pending for quite some time now.  It is very straight-forward and
  only affects what part of cgroup hierarchies are visible.

  After unsharing, mounting a cgroup fs will be scoped to the cgroups
  the task belonged to at the time of unsharing and the cgroup paths
  exposed to userland would be adjusted accordingly"

* 'for-4.6-ns' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: fix and restructure error handling in copy_cgroup_ns()
  cgroup: fix alloc_cgroup_ns() error handling in copy_cgroup_ns()
  Add FS_USERNS_FLAG to cgroup fs
  cgroup: Add documentation for cgroup namespaces
  cgroup: mount cgroupns-root when inside non-init cgroupns
  kernfs: define kernfs_node_dentry
  cgroup: cgroup namespace setns support
  cgroup: introduce cgroup namespaces
  sched: new clone flag CLONE_NEWCGROUP for cgroup namespace
  kernfs: Add API to generate relative kernfs path
2016-03-21 10:05:13 -07:00
Linus Torvalds 643ad15d47 Merge branch 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 protection key support from Ingo Molnar:
 "This tree adds support for a new memory protection hardware feature
  that is available in upcoming Intel CPUs: 'protection keys' (pkeys).

  There's a background article at LWN.net:

      https://lwn.net/Articles/643797/

  The gist is that protection keys allow the encoding of
  user-controllable permission masks in the pte.  So instead of having a
  fixed protection mask in the pte (which needs a system call to change
  and works on a per page basis), the user can map a (handful of)
  protection mask variants and can change the masks runtime relatively
  cheaply, without having to change every single page in the affected
  virtual memory range.

  This allows the dynamic switching of the protection bits of large
  amounts of virtual memory, via user-space instructions.  It also
  allows more precise control of MMU permission bits: for example the
  executable bit is separate from the read bit (see more about that
  below).

  This tree adds the MM infrastructure and low level x86 glue needed for
  that, plus it adds a high level API to make use of protection keys -
  if a user-space application calls:

        mmap(..., PROT_EXEC);

  or

        mprotect(ptr, sz, PROT_EXEC);

  (note PROT_EXEC-only, without PROT_READ/WRITE), the kernel will notice
  this special case, and will set a special protection key on this
  memory range.  It also sets the appropriate bits in the Protection
  Keys User Rights (PKRU) register so that the memory becomes unreadable
  and unwritable.

  So using protection keys the kernel is able to implement 'true'
  PROT_EXEC on x86 CPUs: without protection keys PROT_EXEC implies
  PROT_READ as well.  Unreadable executable mappings have security
  advantages: they cannot be read via information leaks to figure out
  ASLR details, nor can they be scanned for ROP gadgets - and they
  cannot be used by exploits for data purposes either.

  We know about no user-space code that relies on pure PROT_EXEC
  mappings today, but binary loaders could start making use of this new
  feature to map binaries and libraries in a more secure fashion.

  There is other pending pkeys work that offers more high level system
  call APIs to manage protection keys - but those are not part of this
  pull request.

  Right now there's a Kconfig that controls this feature
  (CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS) that is default enabled
  (like most x86 CPU feature enablement code that has no runtime
  overhead), but it's not user-configurable at the moment.  If there's
  any serious problem with this then we can make it configurable and/or
  flip the default"

* 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (38 commits)
  x86/mm/pkeys: Fix mismerge of protection keys CPUID bits
  mm/pkeys: Fix siginfo ABI breakage caused by new u64 field
  x86/mm/pkeys: Fix access_error() denial of writes to write-only VMA
  mm/core, x86/mm/pkeys: Add execute-only protection keys support
  x86/mm/pkeys: Create an x86 arch_calc_vm_prot_bits() for VMA flags
  x86/mm/pkeys: Allow kernel to modify user pkey rights register
  x86/fpu: Allow setting of XSAVE state
  x86/mm: Factor out LDT init from context init
  mm/core, x86/mm/pkeys: Add arch_validate_pkey()
  mm/core, arch, powerpc: Pass a protection key in to calc_vm_flag_bits()
  x86/mm/pkeys: Actually enable Memory Protection Keys in the CPU
  x86/mm/pkeys: Add Kconfig prompt to existing config option
  x86/mm/pkeys: Dump pkey from VMA in /proc/pid/smaps
  x86/mm/pkeys: Dump PKRU with other kernel registers
  mm/core, x86/mm/pkeys: Differentiate instruction fetches
  x86/mm/pkeys: Optimize fault handling in access_error()
  mm/core: Do not enforce PKEY permissions on remote mm access
  um, pkeys: Add UML arch_*_access_permitted() methods
  mm/gup, x86/mm/pkeys: Check VMAs and PTEs for protection keys
  x86/mm/gup: Simplify get_user_pages() PTE bit handling
  ...
2016-03-20 19:08:56 -07:00
Linus Torvalds 26660a4046 Merge branch 'core-objtool-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull 'objtool' stack frame validation from Ingo Molnar:
 "This tree adds a new kernel build-time object file validation feature
  (ONFIG_STACK_VALIDATION=y): kernel stack frame correctness validation.
  It was written by and is maintained by Josh Poimboeuf.

  The motivation: there's a category of hard to find kernel bugs, most
  of them in assembly code (but also occasionally in C code), that
  degrades the quality of kernel stack dumps/backtraces.  These bugs are
  hard to detect at the source code level.  Such bugs result in
  incorrect/incomplete backtraces most of time - but can also in some
  rare cases result in crashes or other undefined behavior.

  The build time correctness checking is done via the new 'objtool'
  user-space utility that was written for this purpose and which is
  hosted in the kernel repository in tools/objtool/.  The tool's (very
  simple) UI and source code design is shaped after Git and perf and
  shares quite a bit of infrastructure with tools/perf (which tooling
  infrastructure sharing effort got merged via perf and is already
  upstream).  Objtool follows the well-known kernel coding style.

  Objtool does not try to check .c or .S files, it instead analyzes the
  resulting .o generated machine code from first principles: it decodes
  the instruction stream and interprets it.  (Right now objtool supports
  the x86-64 architecture.)

  From tools/objtool/Documentation/stack-validation.txt:

   "The kernel CONFIG_STACK_VALIDATION option enables a host tool named
    objtool which runs at compile time.  It has a "check" subcommand
    which analyzes every .o file and ensures the validity of its stack
    metadata.  It enforces a set of rules on asm code and C inline
    assembly code so that stack traces can be reliable.

    Currently it only checks frame pointer usage, but there are plans to
    add CFI validation for C files and CFI generation for asm files.

    For each function, it recursively follows all possible code paths
    and validates the correct frame pointer state at each instruction.

    It also follows code paths involving special sections, like
    .altinstructions, __jump_table, and __ex_table, which can add
    alternative execution paths to a given instruction (or set of
    instructions).  Similarly, it knows how to follow switch statements,
    for which gcc sometimes uses jump tables."

  When this new kernel option is enabled (it's disabled by default), the
  tool, if it finds any suspicious assembly code pattern, outputs
  warnings in compiler warning format:

    warning: objtool: rtlwifi_rate_mapping()+0x2e7: frame pointer state mismatch
    warning: objtool: cik_tiling_mode_table_init()+0x6ce: call without frame pointer save/setup
    warning: objtool:__schedule()+0x3c0: duplicate frame pointer save
    warning: objtool:__schedule()+0x3fd: sibling call from callable instruction with changed frame pointer

  ... so that scripts that pick up compiler warnings will notice them.
  All known warnings triggered by the tool are fixed by the tree, most
  of the commits in fact prepare the kernel to be warning-free.  Most of
  them are bugfixes or cleanups that stand on their own, but there are
  also some annotations of 'special' stack frames for justified cases
  such entries to JIT-ed code (BPF) or really special boot time code.

  There are two other long-term motivations behind this tool as well:

   - To improve the quality and reliability of kernel stack frames, so
     that they can be used for optimized live patching.

   - To create independent infrastructure to check the correctness of
     CFI stack frames at build time.  CFI debuginfo is notoriously
     unreliable and we cannot use it in the kernel as-is without extra
     checking done both on the kernel side and on the build side.

  The quality of kernel stack frames matters to debuggability as well,
  so IMO we can merge this without having to consider the live patching
  or CFI debuginfo angle"

* 'core-objtool-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits)
  objtool: Only print one warning per function
  objtool: Add several performance improvements
  tools: Copy hashtable.h into tools directory
  objtool: Fix false positive warnings for functions with multiple switch statements
  objtool: Rename some variables and functions
  objtool: Remove superflous INIT_LIST_HEAD
  objtool: Add helper macros for traversing instructions
  objtool: Fix false positive warnings related to sibling calls
  objtool: Compile with debugging symbols
  objtool: Detect infinite recursion
  objtool: Prevent infinite recursion in noreturn detection
  objtool: Detect and warn if libelf is missing and don't break the build
  tools: Support relative directory path for 'O='
  objtool: Support CROSS_COMPILE
  x86/asm/decoder: Use explicitly signed chars
  objtool: Enable stack metadata validation on 64-bit x86
  objtool: Add CONFIG_STACK_VALIDATION option
  objtool: Add tool to perform compile-time stack metadata validation
  x86/kprobes: Mark kretprobe_trampoline() stack frame as non-standard
  sched: Always inline context_switch()
  ...
2016-03-20 18:23:21 -07:00
Linus Torvalds 51b3eae8db Merge branch 'stable-4.6' of git://git.infradead.org/users/pcmoore/audit
Pull audit updates from Paul Moore:
 "A small set of patches for audit this time; just three in total and
  one is a spelling fix.

  The two patches with actual content are designed to help prevent new
  instances of auditd from displacing an existing, functioning auditd
  and to generate a log of the attempt.  Not to worry, dead/stuck auditd
  instances can still be replaced by a new instance without problem.

  Nothing controversial, and everything passes our regression suite"

* 'stable-4.6' of git://git.infradead.org/users/pcmoore/audit:
  audit: Fix typo in comment
  audit: log failed attempts to change audit_pid configuration
  audit: stop an old auditd being starved out by a new auditd
2016-03-19 17:52:49 -07:00
Linus Torvalds 1200b6809d Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller:
 "Highlights:

   1) Support more Realtek wireless chips, from Jes Sorenson.

   2) New BPF types for per-cpu hash and arrap maps, from Alexei
      Starovoitov.

   3) Make several TCP sysctls per-namespace, from Nikolay Borisov.

   4) Allow the use of SO_REUSEPORT in order to do per-thread processing
   of incoming TCP/UDP connections.  The muxing can be done using a
   BPF program which hashes the incoming packet.  From Craig Gallek.

   5) Add a multiplexer for TCP streams, to provide a messaged based
      interface.  BPF programs can be used to determine the message
      boundaries.  From Tom Herbert.

   6) Add 802.1AE MACSEC support, from Sabrina Dubroca.

   7) Avoid factorial complexity when taking down an inetdev interface
      with lots of configured addresses.  We were doing things like
      traversing the entire address less for each address removed, and
      flushing the entire netfilter conntrack table for every address as
      well.

   8) Add and use SKB bulk free infrastructure, from Jesper Brouer.

   9) Allow offloading u32 classifiers to hardware, and implement for
      ixgbe, from John Fastabend.

  10) Allow configuring IRQ coalescing parameters on a per-queue basis,
      from Kan Liang.

  11) Extend ethtool so that larger link mode masks can be supported.
      From David Decotigny.

  12) Introduce devlink, which can be used to configure port link types
      (ethernet vs Infiniband, etc.), port splitting, and switch device
      level attributes as a whole.  From Jiri Pirko.

  13) Hardware offload support for flower classifiers, from Amir Vadai.

  14) Add "Local Checksum Offload".  Basically, for a tunneled packet
      the checksum of the outer header is 'constant' (because with the
      checksum field filled into the inner protocol header, the payload
      of the outer frame checksums to 'zero'), and we can take advantage
      of that in various ways.  From Edward Cree"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1548 commits)
  bonding: fix bond_get_stats()
  net: bcmgenet: fix dma api length mismatch
  net/mlx4_core: Fix backward compatibility on VFs
  phy: mdio-thunder: Fix some Kconfig typos
  lan78xx: add ndo_get_stats64
  lan78xx: handle statistics counter rollover
  RDS: TCP: Remove unused constant
  RDS: TCP: Add sysctl tunables for sndbuf/rcvbuf on rds-tcp socket
  net: smc911x: convert pxa dma to dmaengine
  team: remove duplicate set of flag IFF_MULTICAST
  bonding: remove duplicate set of flag IFF_MULTICAST
  net: fix a comment typo
  ethernet: micrel: fix some error codes
  ip_tunnels, bpf: define IP_TUNNEL_OPTS_MAX and use it
  bpf, dst: add and use dst_tclassid helper
  bpf: make skb->tc_classid also readable
  net: mvneta: bm: clarify dependencies
  cls_bpf: reset class and reuse major in da
  ldmvsw: Checkpatch sunvnet.c and sunvnet_common.c
  ldmvsw: Add ldmvsw.c driver code
  ...
2016-03-19 10:05:34 -07:00
Linus Torvalds 6b5f04b6cf Merge branch 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
 "cgroup changes for v4.6-rc1.  No userland visible behavior changes in
  this pull request.  I'll send out a separate pull request for the
  addition of cgroup namespace support.

   - The biggest change is the revamping of cgroup core task migration
     and controller handling logic.  There are quite a few places where
     controllers and tasks are manipulated.  Previously, many of those
     places implemented custom operations for each specific use case
     assuming specific starting conditions.  While this worked, it makes
     the code fragile and difficult to follow.

     The bulk of this pull request restructures these operations so that
     most related operations are performed through common helpers which
     implement recursive (subtrees are always processed consistently)
     and idempotent (they make cgroup hierarchy converge to the target
     state rather than performing operations assuming specific starting
     conditions).  This makes the code a lot easier to understand,
     verify and extend.

   - Implicit controller support is added.  This is primarily for using
     perf_event on the v2 hierarchy so that perf can match cgroup v2
     path without requiring the user to do anything special.  The kernel
     portion of perf_event changes is acked but userland changes are
     still pending review.

   - cgroup_no_v1= boot parameter added to ease testing cgroup v2 in
     certain environments.

   - There is a regression introduced during v4.4 devel cycle where
     attempts to migrate zombie tasks can mess up internal object
     management.  This was fixed earlier this week and included in this
     pull request w/ stable cc'd.

   - Misc non-critical fixes and improvements"

* 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (44 commits)
  cgroup: avoid false positive gcc-6 warning
  cgroup: ignore css_sets associated with dead cgroups during migration
  Documentation: cgroup v2: Trivial heading correction.
  cgroup: implement cgroup_subsys->implicit_on_dfl
  cgroup: use css_set->mg_dst_cgrp for the migration target cgroup
  cgroup: make cgroup[_taskset]_migrate() take cgroup_root instead of cgroup
  cgroup: move migration destination verification out of cgroup_migrate_prepare_dst()
  cgroup: fix incorrect destination cgroup in cgroup_update_dfl_csses()
  cgroup: Trivial correction to reflect controller.
  cgroup: remove stale item in cgroup-v1 document INDEX file.
  cgroup: update css iteration in cgroup_update_dfl_csses()
  cgroup: allocate 2x cgrp_cset_links when setting up a new root
  cgroup: make cgroup_calc_subtree_ss_mask() take @this_ss_mask
  cgroup: reimplement rebind_subsystems() using cgroup_apply_control() and friends
  cgroup: use cgroup_apply_enable_control() in cgroup creation path
  cgroup: combine cgroup_mutex locking and offline css draining
  cgroup: factor out cgroup_{apply|finalize}_control() from cgroup_subtree_control_write()
  cgroup: introduce cgroup_{save|propagate|restore}_control()
  cgroup: make cgroup_drain_offline() and cgroup_apply_control_{disable|enable}() recursive
  cgroup: factor out cgroup_apply_control_enable() from cgroup_subtree_control_write()
  ...
2016-03-18 20:25:49 -07:00
Linus Torvalds ef504fa591 Merge branch 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue updates from Tejun Heo:
 "Three trivial workqueue changes"

* 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: Fix comment for work_on_cpu()
  sched/core: Get rid of 'cpu' argument in wq_worker_sleeping()
  workqueue: Replace usage of init_name with dev_set_name()
2016-03-18 20:05:39 -07:00
Linus Torvalds 814a2bf957 Merge branch 'akpm' (patches from Andrew)
Merge second patch-bomb from Andrew Morton:

 - a couple of hotfixes

 - the rest of MM

 - a new timer slack control in procfs

 - a couple of procfs fixes

 - a few misc things

 - some printk tweaks

 - lib/ updates, notably to radix-tree.

 - add my and Nick Piggin's old userspace radix-tree test harness to
   tools/testing/radix-tree/.  Matthew said it was a godsend during the
   radix-tree work he did.

 - a few code-size improvements, switching to __always_inline where gcc
   screwed up.

 - partially implement character sets in sscanf

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (118 commits)
  sscanf: implement basic character sets
  lib/bug.c: use common WARN helper
  param: convert some "on"/"off" users to strtobool
  lib: add "on"/"off" support to kstrtobool
  lib: update single-char callers of strtobool()
  lib: move strtobool() to kstrtobool()
  include/linux/unaligned: force inlining of byteswap operations
  include/uapi/linux/byteorder, swab: force inlining of some byteswap operations
  include/asm-generic/atomic-long.h: force inlining of some atomic_long operations
  usb: common: convert to use match_string() helper
  ide: hpt366: convert to use match_string() helper
  ata: hpt366: convert to use match_string() helper
  power: ab8500: convert to use match_string() helper
  power: charger_manager: convert to use match_string() helper
  drm/edid: convert to use match_string() helper
  pinctrl: convert to use match_string() helper
  device property: convert to use match_string() helper
  lib/string: introduce match_string() helper
  radix-tree tests: add test for radix_tree_iter_next
  radix-tree tests: add regression3 test
  ...
2016-03-18 19:26:54 -07:00
Linus Torvalds 0f49fc95b8 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching
Pull livepatching update from Jiri Kosina:

 - cleanup of module notifiers; this depends on a module.c cleanup which
   has been acked by Rusty; from Jessica Yu

 - small assorted fixes and MAINTAINERS update

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
  livepatch/module: remove livepatch module notifier
  modules: split part of complete_formation() into prepare_coming_module()
  livepatch: Update maintainers
  livepatch: Fix the error message about unresolvable ambiguity
  klp: remove CONFIG_LIVEPATCH dependency from klp headers
  klp: remove superfluous errors in asm/livepatch.h
2016-03-17 21:46:32 -07:00
Linus Torvalds 49dc2b7173 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
Pull trivial tree updates from Jiri Kosina.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial:
  drivers/rtc: broken link fix
  drm/i915 Fix typos in i915_gem_fence.c
  Docs: fix missing word in REPORTING-BUGS
  lib+mm: fix few spelling mistakes
  MAINTAINERS: add git URL for APM driver
  treewide: Fix typo in printk
2016-03-17 21:38:27 -07:00
Josh Poimboeuf 2553b67a1f lib/bug.c: use common WARN helper
The traceoff_on_warning option doesn't have any effect on s390, powerpc,
arm64, parisc, and sh because there are two different types of WARN
implementations:

1) The above mentioned architectures treat WARN() as a special case of a
   BUG() exception.  They handle warnings in report_bug() in lib/bug.c.

2) All other architectures just call warn_slowpath_*() directly.  Their
   warnings are handled in warn_slowpath_common() in kernel/panic.c.

Support traceoff_on_warning on all architectures and prevent any future
divergence by using a single common function to emit the warning.

Also remove the '()' from '%pS()', because the parentheses look funky:

  [   45.607629] WARNING: at /root/warn_mod/warn_mod.c:17 .init_dummy+0x20/0x40 [warn_mod]()

Reported-by: Chunyu Hu <chuhu@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Prarit Bhargava <prarit@redhat.com>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17 15:09:34 -07:00
Kees Cook 4cc7ecb7f2 param: convert some "on"/"off" users to strtobool
This changes several users of manual "on"/"off" parsing to use
strtobool.

Some side-effects:
- these uses will now parse y/n/1/0 meaningfully too
- the early_param uses will now bubble up parse errors

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Amitkumar Karwar <akarwar@marvell.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Joe Perches <joe@perches.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Nishant Sarmukadam <nishants@marvell.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Steve French <sfrench@samba.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17 15:09:34 -07:00
Ivan Delalande f468908bb5 printk: add clear_idx symbol to vmcoreinfo
This allows us to extract from the vmcore only the messages emitted
since the last time the ring buffer was cleared.  We just have to make
sure its value is always up-to-date, when old messages are discarded to
free space in log_make_free_space() for example.

Signed-off-by: Zeyu Zhao <zzy8200@gmail.com>
Signed-off-by: Ivan Delalande <colona@arista.com>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17 15:09:34 -07:00
Sergey Senozhatsky adaf6590ee printk: check CON_ENABLED in have_callable_console()
have_callable_console() must also test CON_ENABLED bit, not just
CON_ANYTIME.  We may have disabled CON_ANYTIME console so printk can
wrongly assume that it's safe to call_console_drivers().

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Jan Kara <jack@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Kyle McMartin <kyle@kernel.org>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Calvin Owens <calvinowens@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17 15:09:34 -07:00
Sergey Senozhatsky 6b97a20d3a printk: set may_schedule for some of console_trylock() callers
console_unlock() allows to cond_resched() if its caller has set
`console_may_schedule' to 1, since 8d91f8b153 ("printk: do
cond_resched() between lines while outputting to consoles").

The rules are:
-- console_lock() always sets `console_may_schedule' to 1
-- console_trylock() always sets `console_may_schedule' to 0

However, console_trylock() callers (among them is printk()) do not
always call printk() from atomic contexts, and some of them can
cond_resched() in console_unlock(), so console_trylock() can set
`console_may_schedule' to 1 for such processes.

For !CONFIG_PREEMPT_COUNT kernels, however, console_trylock() always
sets `console_may_schedule' to 0.

It's possible to drop explicit preempt_disable()/preempt_enable() in
vprintk_emit(), because console_unlock() and console_trylock() are now
smart enough:
 a) console_unlock() does not cond_resched() when it's unsafe
    (console_trylock() takes care of that)
 b) console_unlock() does can_use_console() check.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Jan Kara <jack@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Kyle McMartin <kyle@kernel.org>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Calvin Owens <calvinowens@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17 15:09:34 -07:00
Sergey Senozhatsky a8199371af printk: move can_use_console() out of console_trylock_for_printk()
console_unlock() allows to cond_resched() if its caller has set
`console_may_schedule' to 1 (this functionality is present since
8d91f8b153 ("printk: do cond_resched() between lines while outputting
to consoles").

The rules are:
-- console_lock() always sets `console_may_schedule' to 1
-- console_trylock() always sets `console_may_schedule' to 0

printk() calls console_unlock() with preemption desabled, which
basically can lead to RCU stalls, watchdog soft lockups, etc.  if
something is simultaneously calling printk() frequent enough (IOW,
console_sem owner always has new data to send to console divers and
can't leave console_unlock() for a long time).

printk()->console_trylock() callers do not necessarily execute in atomic
contexts, and some of them can cond_resched() in console_unlock().
console_trylock() can set `console_may_schedule' to 1 (allow
cond_resched() later in consoe_unlock()) when it's safe.

This patch (of 3):

vprintk_emit() disables preemption around console_trylock_for_printk()
and console_unlock() calls for a strong reason -- can_use_console()
check.  The thing is that vprintl_emit() can be called on a CPU that is
not fully brought up yet (!cpu_online()), which potentially can cause
problems if console driver wants to access per-cpu data.  A console
driver can explicitly state that it's safe to call it from !online cpu
by setting CON_ANYTIME bit in console ->flags.  That's why for
!cpu_online() can_use_console() iterates all the console to find out if
there is a CON_ANYTIME console, otherwise console_unlock() must be
avoided.

can_use_console() ensures that console_unlock() call is safe in
vprintk_emit() only; console_lock() and console_trylock() are not
covered by this check.  Even though call_console_drivers(), invoked from
console_cont_flush() and console_unlock(), tests `!cpu_online() &&
CON_ANYTIME' for_each_console(), it may be too late, which can result in
messages loss.

Assume that we have 2 cpus -- CPU0 is online, CPU1 is !online, and no
CON_ANYTIME consoles available.

CPU0 online                        CPU1 !online
                                 console_trylock()
                                 ...
                                 console_unlock()
                                   console_cont_flush
                                     spin_lock logbuf_lock
                                     if (!cont.len) {
                                        spin_unlock logbuf_lock
                                        return
                                     }
                                   for (;;) {
vprintk_emit
  spin_lock logbuf_lock
  log_store
  spin_unlock logbuf_lock
                                     spin_lock logbuf_lock
  !console_trylock_for_printk        msg_print_text
 return                              console_idx = log_next()
                                     console_seq++
                                     console_prev = msg->flags
                                     spin_unlock logbuf_lock

                                     call_console_drivers()
                                       for_each_console(con) {
                                         if (!cpu_online() &&
                                             !(con->flags & CON_ANYTIME))
                                                 continue;
                                         }
                                   /*
                                    * no message printed, we lost it
                                    */
vprintk_emit
  spin_lock logbuf_lock
  log_store
  spin_unlock logbuf_lock
  !console_trylock_for_printk
 return
                                   /*
                                    * go to the beginning of the loop,
                                    * find out there are new messages,
                                    * lose it
                                    */
                                   }

console_trylock()/console_lock() call on CPU1 may come from cpu
notifiers registered on that CPU.  Since notifiers are not getting
unregistered when CPU is going DOWN, all of the notifiers receive
notifications during CPU UP.  For example, on my x86_64, I see around 50
notification sent from offline CPU to itself

 [swapper/2] from cpu:2 to:2 action:CPU_STARTING hotplug_hrtick
 [swapper/2] from cpu:2 to:2 action:CPU_STARTING blk_mq_main_cpu_notify
 [swapper/2] from cpu:2 to:2 action:CPU_STARTING blk_mq_queue_reinit_notify
 [swapper/2] from cpu:2 to:2 action:CPU_STARTING console_cpu_notify

while doing
  echo 0 > /sys/devices/system/cpu/cpu2/online
  echo 1 > /sys/devices/system/cpu/cpu2/online

So grabbing the console_sem lock while CPU is !online is possible,
in theory.

This patch moves can_use_console() check out of
console_trylock_for_printk().  Instead it calls it in console_unlock(),
so now console_lock()/console_unlock() are also 'protected' by
can_use_console().  This also means that console_trylock_for_printk() is
not really needed anymore and can be removed.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Jan Kara <jack@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Kyle McMartin <kyle@kernel.org>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Calvin Owens <calvinowens@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17 15:09:34 -07:00
John Stultz da8b44d5a9 timer: convert timer_slack_ns from unsigned long to u64
This patchset introduces a /proc/<pid>/timerslack_ns interface which
would allow controlling processes to be able to set the timerslack value
on other processes in order to save power by avoiding wakeups (Something
Android currently does via out-of-tree patches).

The first patch tries to fix the internal timer_slack_ns usage which was
defined as a long, which limits the slack range to ~4 seconds on 32bit
systems.  It converts it to a u64, which provides the same basically
unlimited slack (500 years) on both 32bit and 64bit machines.

The second patch introduces the /proc/<pid>/timerslack_ns interface
which allows the full 64bit slack range for a task to be read or set on
both 32bit and 64bit machines.

With these two patches, on a 32bit machine, after setting the slack on
bash to 10 seconds:

$ time sleep 1

real    0m10.747s
user    0m0.001s
sys     0m0.005s

The first patch is a little ugly, since I had to chase the slack delta
arguments through a number of functions converting them to u64s.  Let me
know if it makes sense to break that up more or not.

Other than that things are fairly straightforward.

This patch (of 2):

The timer_slack_ns value in the task struct is currently a unsigned
long.  This means that on 32bit applications, the maximum slack is just
over 4 seconds.  However, on 64bit machines, its much much larger (~500
years).

This disparity could make application development a little (as well as
the default_slack) to a u64.  This means both 32bit and 64bit systems
have the same effective internal slack range.

Now the existing ABI via PR_GET_TIMERSLACK and PR_SET_TIMERSLACK specify
the interface as a unsigned long, so we preserve that limitation on
32bit systems, where SET_TIMERSLACK can only set the slack to a unsigned
long value, and GET_TIMERSLACK will return ULONG_MAX if the slack is
actually larger then what can be stored by an unsigned long.

This patch also modifies hrtimer functions which specified the slack
delta as a unsigned long.

Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Oren Laadan <orenl@cellrox.com>
Cc: Ruchi Kandoi <kandoiruchi@google.com>
Cc: Rom Lemarchand <romlem@android.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17 15:09:34 -07:00
Johannes Weiner 795ae7a0de mm: scale kswapd watermarks in proportion to memory
In machines with 140G of memory and enterprise flash storage, we have
seen read and write bursts routinely exceed the kswapd watermarks and
cause thundering herds in direct reclaim.  Unfortunately, the only way
to tune kswapd aggressiveness is through adjusting min_free_kbytes - the
system's emergency reserves - which is entirely unrelated to the
system's latency requirements.  In order to get kswapd to maintain a
250M buffer of free memory, the emergency reserves need to be set to 1G.
That is a lot of memory wasted for no good reason.

On the other hand, it's reasonable to assume that allocation bursts and
overall allocation concurrency scale with memory capacity, so it makes
sense to make kswapd aggressiveness a function of that as well.

Change the kswapd watermark scale factor from the currently fixed 25% of
the tunable emergency reserve to a tunable 0.1% of memory.

Beyond 1G of memory, this will produce bigger watermark steps than the
current formula in default settings.  Ensure that the new formula never
chooses steps smaller than that, i.e.  25% of the emergency reserve.

On a 140G machine, this raises the default watermark steps - the
distance between min and low, and low and high - from 16M to 143M.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17 15:09:34 -07:00
Vladimir Davydov 12580e4b54 mm: memcontrol: report kernel stack usage in cgroup2 memory.stat
Show how much memory is allocated to kernel stacks.

Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17 15:09:34 -07:00