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  1. 13 8月, 2019 1 次提交
    • A
      fanotify, inotify, dnotify, security: add security hook for fs notifications · ac5656d8
      由 Aaron Goidel 提交于 
      As of now, setting watches on filesystem objects has, at most, applied a
check for read access to the inode, and in the case of fanotify, requires
CAP_SYS_ADMIN. No specific security hook or permission check has been
provided to control the setting of watches. Using any of inotify, dnotify,
or fanotify, it is possible to observe, not only write-like operations, but
even read access to a file. Modeling the watch as being merely a read from
the file is insufficient for the needs of SELinux. This is due to the fact
that read access should not necessarily imply access to information about
when another process reads from a file. Furthermore, fanotify watches grant
more power to an application in the form of permission events. While
notification events are solely, unidirectional (i.e. they only pass
information to the receiving application), permission events are blocking.
Permission events make a request to the receiving application which will
then reply with a decision as to whether or not that action may be
completed. This causes the issue of the watching application having the
ability to exercise control over the triggering process. Without drawing a
distinction within the permission check, the ability to read would imply
the greater ability to control an application. Additionally, mount and
superblock watches apply to all files within the same mount or superblock.
Read access to one file should not necessarily imply the ability to watch
all files accessed within a given mount or superblock.

In order to solve these issues, a new LSM hook is implemented and has been
placed within the system calls for marking filesystem objects with inotify,
fanotify, and dnotify watches. These calls to the hook are placed at the
point at which the target path has been resolved and are provided with the
path struct, the mask of requested notification events, and the type of
object on which the mark is being set (inode, superblock, or mount). The
mask and obj_type have already been translated into common FS_* values
shared by the entirety of the fs notification infrastructure. The path
struct is passed rather than just the inode so that the mount is available,
particularly for mount watches. This also allows for use of the hook by
pathname-based security modules. However, since the hook is intended for
use even by inode based security modules, it is not placed under the
CONFIG_SECURITY_PATH conditional. Otherwise, the inode-based security
modules would need to enable all of the path hooks, even though they do not
use any of them.

This only provides a hook at the point of setting a watch, and presumes
that permission to set a particular watch implies the ability to receive
all notification about that object which match the mask. This is all that
is required for SELinux. If other security modules require additional hooks
or infrastructure to control delivery of notification, these can be added
by them. It does not make sense for us to propose hooks for which we have
no implementation. The understanding that all notifications received by the
requesting application are all strictly of a type for which the application
has been granted permission shows that this implementation is sufficient in
its coverage.

Security modules wishing to provide complete control over fanotify must
also implement a security_file_open hook that validates that the access
requested by the watching application is authorized. Fanotify has the issue
that it returns a file descriptor with the file mode specified during
fanotify_init() to the watching process on event. This is already covered
by the LSM security_file_open hook if the security module implements
checking of the requested file mode there. Otherwise, a watching process
can obtain escalated access to a file for which it has not been authorized.

The selinux_path_notify hook implementation works by adding five new file
permissions: watch, watch_mount, watch_sb, watch_reads, and watch_with_perm
(descriptions about which will follow), and one new filesystem permission:
watch (which is applied to superblock checks). The hook then decides which
subset of these permissions must be held by the requesting application
based on the contents of the provided mask and the obj_type. The
selinux_file_open hook already checks the requested file mode and therefore
ensures that a watching process cannot escalate its access through
fanotify.

The watch, watch_mount, and watch_sb permissions are the baseline
permissions for setting a watch on an object and each are a requirement for
any watch to be set on a file, mount, or superblock respectively. It should
be noted that having either of the other two permissions (watch_reads and
watch_with_perm) does not imply the watch, watch_mount, or watch_sb
permission. Superblock watches further require the filesystem watch
permission to the superblock. As there is no labeled object in view for
mounts, there is no specific check for mount watches beyond watch_mount to
the inode. Such a check could be added in the future, if a suitable labeled
object existed representing the mount.

The watch_reads permission is required to receive notifications from
read-exclusive events on filesystem objects. These events include accessing
a file for the purpose of reading and closing a file which has been opened
read-only. This distinction has been drawn in order to provide a direct
indication in the policy for this otherwise not obvious capability. Read
access to a file should not necessarily imply the ability to observe read
events on a file.

Finally, watch_with_perm only applies to fanotify masks since it is the
only way to set a mask which allows for the blocking, permission event.
This permission is needed for any watch which is of this type. Though
fanotify requires CAP_SYS_ADMIN, this is insufficient as it gives implicit
trust to root, which we do not do, and does not support least privilege.
Signed-off-by: NAaron Goidel <acgoide@tycho.nsa.gov>
Acked-by: NCasey Schaufler <casey@schaufler-ca.com>
Acked-by: NJan Kara <jack@suse.cz>
Signed-off-by: NPaul Moore <paul@paul-moore.com>
      ac5656d8
  3. 19 5月, 2019 2 次提交
    • F
      panic: add an option to replay all the printk message in buffer · de6da1e8
      由 Feng Tang 提交于 
      Currently on panic, kernel will lower the loglevel and print out pending
printk msg only with console_flush_on_panic().

Add an option for users to configure the "panic_print" to replay all
dmesg in buffer, some of which they may have never seen due to the
loglevel setting, which will help panic debugging .

[feng.tang@intel.com: keep the original console_flush_on_panic() inside panic()]
  Link: http://lkml.kernel.org/r/1556199137-14163-1-git-send-email-feng.tang@intel.com
[feng.tang@intel.com: use logbuf lock to protect the console log index]
  Link: http://lkml.kernel.org/r/1556269868-22654-1-git-send-email-feng.tang@intel.com
Link: http://lkml.kernel.org/r/1556095872-36838-1-git-send-email-feng.tang@intel.comSigned-off-by: NFeng Tang <feng.tang@intel.com>
Reviewed-by: NPetr Mladek <pmladek@suse.com>
Cc: Aaro Koskinen <aaro.koskinen@nokia.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Borislav Petkov <bp@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      de6da1e8
    • U
      mm/vmalloc.c: keep track of free blocks for vmap allocation · 68ad4a33
      由 Uladzislau Rezki (Sony) 提交于 
      Patch series "improve vmap allocation", v3.

Objective
---------

Please have a look for the description at:

  https://lkml.org/lkml/2018/10/19/786

but let me also summarize it a bit here as well.

The current implementation has O(N) complexity. Requests with different
permissive parameters can lead to long allocation time. When i say
"long" i mean milliseconds.

Description
-----------

This approach organizes the KVA memory layout into free areas of the
1-ULONG_MAX range, i.e.  an allocation is done over free areas lookups,
instead of finding a hole between two busy blocks.  It allows to have
lower number of objects which represent the free space, therefore to have
less fragmented memory allocator.  Because free blocks are always as large
as possible.

It uses the augment tree where all free areas are sorted in ascending
order of va->va_start address in pair with linked list that provides
O(1) access to prev/next elements.

Since the tree is augment, we also maintain the "subtree_max_size" of VA
that reflects a maximum available free block in its left or right
sub-tree.  Knowing that, we can easily traversal toward the lowest (left
most path) free area.

Allocation: ~O(log(N)) complexity.  It is sequential allocation method
therefore tends to maximize locality.  The search is done until a first
suitable block is large enough to encompass the requested parameters.
Bigger areas are split.

I copy paste here the description of how the area is split, since i
described it in https://lkml.org/lkml/2018/10/19/786

<snip>

A free block can be split by three different ways.  Their names are
FL_FIT_TYPE, LE_FIT_TYPE/RE_FIT_TYPE and NE_FIT_TYPE, i.e.  they
correspond to how requested size and alignment fit to a free block.

FL_FIT_TYPE - in this case a free block is just removed from the free
list/tree because it fully fits.  Comparing with current design there is
an extra work with rb-tree updating.

LE_FIT_TYPE/RE_FIT_TYPE - left/right edges fit.  In this case what we do
is just cutting a free block.  It is as fast as a current design.  Most of
the vmalloc allocations just end up with this case, because the edge is
always aligned to 1.

NE_FIT_TYPE - Is much less common case.  Basically it happens when
requested size and alignment does not fit left nor right edges, i.e.  it
is between them.  In this case during splitting we have to build a
remaining left free area and place it back to the free list/tree.

Comparing with current design there are two extra steps.  First one is we
have to allocate a new vmap_area structure.  Second one we have to insert
that remaining free block to the address sorted list/tree.

In order to optimize a first case there is a cache with free_vmap objects.
Instead of allocating from slab we just take an object from the cache and
reuse it.

Second one is pretty optimized.  Since we know a start point in the tree
we do not do a search from the top.  Instead a traversal begins from a
rb-tree node we split.
<snip>

De-allocation.  ~O(log(N)) complexity.  An area is not inserted straight
away to the tree/list, instead we identify the spot first, checking if it
can be merged around neighbors.  The list provides O(1) access to
prev/next, so it is pretty fast to check it.  Summarizing.  If merged then
large coalesced areas are created, if not the area is just linked making
more fragments.

There is one more thing that i should mention here.  After modification of
VA node, its subtree_max_size is updated if it was/is the biggest area in
its left or right sub-tree.  Apart of that it can also be populated back
to upper levels to fix the tree.  For more details please have a look at
the __augment_tree_propagate_from() function and the description.

Tests and stressing
-------------------

I use the "test_vmalloc.sh" test driver available under
"tools/testing/selftests/vm/" since 5.1-rc1 kernel.  Just trigger "sudo
./test_vmalloc.sh" to find out how to deal with it.

Tested on different platforms including x86_64/i686/ARM64/x86_64_NUMA.
Regarding last one, i do not have any physical access to NUMA system,
therefore i emulated it.  The time of stressing is days.

If you run the test driver in "stress mode", you also need the patch that
is in Andrew's tree but not in Linux 5.1-rc1.  So, please apply it:

http://git.cmpxchg.org/cgit.cgi/linux-mmotm.git/commit/?id=e0cf7749bade6da318e98e934a24d8b62fab512c

After massive testing, i have not identified any problems like memory
leaks, crashes or kernel panics.  I find it stable, but more testing would
be good.

Performance analysis
--------------------

I have used two systems to test.  One is i5-3320M CPU @ 2.60GHz and
another is HiKey960(arm64) board.  i5-3320M runs on 4.20 kernel, whereas
Hikey960 uses 4.15 kernel.  I have both system which could run on 5.1-rc1
as well, but the results have not been ready by time i an writing this.

Currently it consist of 8 tests.  There are three of them which correspond
to different types of splitting(to compare with default).  We have 3
ones(see above).  Another 5 do allocations in different conditions.

a) sudo ./test_vmalloc.sh performance

When the test driver is run in "performance" mode, it runs all available
tests pinned to first online CPU with sequential execution test order.  We
do it in order to get stable and repeatable results.  Take a look at time
difference in "long_busy_list_alloc_test".  It is not surprising because
the worst case is O(N).

# i5-3320M
How many cycles all tests took:
CPU0=646919905370(default) cycles vs CPU0=193290498550(patched) cycles

# See detailed table with results here:
ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/i5-3320M_performance_default.txt
ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/i5-3320M_performance_patched.txt

# Hikey960 8x CPUs
How many cycles all tests took:
CPU0=3478683207 cycles vs CPU0=463767978 cycles

# See detailed table with results here:
ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/HiKey960_performance_default.txt
ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/HiKey960_performance_patched.txt

b) time sudo ./test_vmalloc.sh test_repeat_count=1

With this configuration, all tests are run on all available online CPUs.
Before running each CPU shuffles its tests execution order.  It gives
random allocation behaviour.  So it is rough comparison, but it puts in
the picture for sure.

# i5-3320M
<default>            vs            <patched>
real    101m22.813s                real    0m56.805s
user    0m0.011s                   user    0m0.015s
sys     0m5.076s                   sys     0m0.023s

# See detailed table with results here:
ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/i5-3320M_test_repeat_count_1_default.txt
ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/i5-3320M_test_repeat_count_1_patched.txt

# Hikey960 8x CPUs
<default>            vs            <patched>
real    unknown                    real    4m25.214s
user    unknown                    user    0m0.011s
sys     unknown                    sys     0m0.670s

I did not manage to complete this test on "default Hikey960" kernel
version.  After 24 hours it was still running, therefore i had to cancel
it.  That is why real/user/sys are "unknown".

This patch (of 3):

Currently an allocation of the new vmap area is done over busy list
iteration(complexity O(n)) until a suitable hole is found between two busy
areas.  Therefore each new allocation causes the list being grown.  Due to
over fragmented list and different permissive parameters an allocation can
take a long time.  For example on embedded devices it is milliseconds.

This patch organizes the KVA memory layout into free areas of the
1-ULONG_MAX range.  It uses an augment red-black tree that keeps blocks
sorted by their offsets in pair with linked list keeping the free space in
order of increasing addresses.

Nodes are augmented with the size of the maximum available free block in
its left or right sub-tree.  Thus, that allows to take a decision and
traversal toward the block that will fit and will have the lowest start
address, i.e.  it is sequential allocation.

Allocation: to allocate a new block a search is done over the tree until a
suitable lowest(left most) block is large enough to encompass: the
requested size, alignment and vstart point.  If the block is bigger than
requested size - it is split.

De-allocation: when a busy vmap area is freed it can either be merged or
inserted to the tree.  Red-black tree allows efficiently find a spot
whereas a linked list provides a constant-time access to previous and next
blocks to check if merging can be done.  In case of merging of
de-allocated memory chunk a large coalesced area is created.

Complexity: ~O(log(N))

[urezki@gmail.com: v3]
  Link: http://lkml.kernel.org/r/20190402162531.10888-2-urezki@gmail.com
[urezki@gmail.com: v4]
  Link: http://lkml.kernel.org/r/20190406183508.25273-2-urezki@gmail.com
Link: http://lkml.kernel.org/r/20190321190327.11813-2-urezki@gmail.comSigned-off-by: NUladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: NRoman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      68ad4a33
  5. 18 5月, 2019 1 次提交
  7. 17 5月, 2019 2 次提交
  9. 16 5月, 2019 5 次提交
    • D
      rxrpc: Allow the kernel to mark a call as being non-interruptible · b960a34b
      由 David Howells 提交于 
      Allow kernel services using AF_RXRPC to indicate that a call should be
non-interruptible.  This allows kafs to make things like lock-extension and
writeback data storage calls non-interruptible.

If this is set, signals will be ignored for operations on that call where
possible - such as waiting to get a call channel on an rxrpc connection.

It doesn't prevent UDP sendmsg from being interrupted, but that will be
handled by packet retransmission.

rxrpc_kernel_recv_data() isn't affected by this since that never waits,
preferring instead to return -EAGAIN and leave the waiting to the caller.

Userspace initiated calls can't be set to be uninterruptible at this time.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
      b960a34b
    • D
      rxrpc: Provide kernel interface to set max lifespan on a call · bbd172e3
      由 David Howells 提交于 
      Provide an interface to set max lifespan on a call from inside of the
kernel without having to call kernel_sendmsg().
Signed-off-by: NDavid Howells <dhowells@redhat.com>
      bbd172e3
    • S
      clk: Remove io.h from clk-provider.h · 62e59c4e
      由 Stephen Boyd 提交于 
      Now that we've gotten rid of clk_readl() we can remove io.h from the
clk-provider header and push out the io.h include to any code that isn't
already including the io.h header but using things like readl/writel,
etc.

Found with this grep:

  git grep -l clk-provider.h | grep '.c$' | xargs git grep -L 'linux/io.h' | \
  	xargs git grep -l \
	-e '\<__iowrite32_copy\>' --or \
	-e '\<__ioread32_copy\>' --or \
	-e '\<__iowrite64_copy\>' --or \
	-e '\<ioremap_page_range\>' --or \
	-e '\<ioremap_huge_init\>' --or \
	-e '\<arch_ioremap_pud_supported\>' --or \
	-e '\<arch_ioremap_pmd_supported\>' --or \
	-e '\<devm_ioport_map\>' --or \
	-e '\<devm_ioport_unmap\>' --or \
	-e '\<IOMEM_ERR_PTR\>' --or \
	-e '\<devm_ioremap\>' --or \
	-e '\<devm_ioremap_nocache\>' --or \
	-e '\<devm_ioremap_wc\>' --or \
	-e '\<devm_iounmap\>' --or \
	-e '\<devm_ioremap_release\>' --or \
	-e '\<devm_memremap\>' --or \
	-e '\<devm_memunmap\>' --or \
	-e '\<__devm_memremap_pages\>' --or \
	-e '\<pci_remap_cfgspace\>' --or \
	-e '\<arch_has_dev_port\>' --or \
	-e '\<arch_phys_wc_add\>' --or \
	-e '\<arch_phys_wc_del\>' --or \
	-e '\<memremap\>' --or \
	-e '\<memunmap\>' --or \
	-e '\<arch_io_reserve_memtype_wc\>' --or \
	-e '\<arch_io_free_memtype_wc\>' --or \
	-e '\<__io_aw\>' --or \
	-e '\<__io_pbw\>' --or \
	-e '\<__io_paw\>' --or \
	-e '\<__io_pbr\>' --or \
	-e '\<__io_par\>' --or \
	-e '\<__raw_readb\>' --or \
	-e '\<__raw_readw\>' --or \
	-e '\<__raw_readl\>' --or \
	-e '\<__raw_readq\>' --or \
	-e '\<__raw_writeb\>' --or \
	-e '\<__raw_writew\>' --or \
	-e '\<__raw_writel\>' --or \
	-e '\<__raw_writeq\>' --or \
	-e '\<readb\>' --or \
	-e '\<readw\>' --or \
	-e '\<readl\>' --or \
	-e '\<readq\>' --or \
	-e '\<writeb\>' --or \
	-e '\<writew\>' --or \
	-e '\<writel\>' --or \
	-e '\<writeq\>' --or \
	-e '\<readb_relaxed\>' --or \
	-e '\<readw_relaxed\>' --or \
	-e '\<readl_relaxed\>' --or \
	-e '\<readq_relaxed\>' --or \
	-e '\<writeb_relaxed\>' --or \
	-e '\<writew_relaxed\>' --or \
	-e '\<writel_relaxed\>' --or \
	-e '\<writeq_relaxed\>' --or \
	-e '\<readsb\>' --or \
	-e '\<readsw\>' --or \
	-e '\<readsl\>' --or \
	-e '\<readsq\>' --or \
	-e '\<writesb\>' --or \
	-e '\<writesw\>' --or \
	-e '\<writesl\>' --or \
	-e '\<writesq\>' --or \
	-e '\<inb\>' --or \
	-e '\<inw\>' --or \
	-e '\<inl\>' --or \
	-e '\<outb\>' --or \
	-e '\<outw\>' --or \
	-e '\<outl\>' --or \
	-e '\<inb_p\>' --or \
	-e '\<inw_p\>' --or \
	-e '\<inl_p\>' --or \
	-e '\<outb_p\>' --or \
	-e '\<outw_p\>' --or \
	-e '\<outl_p\>' --or \
	-e '\<insb\>' --or \
	-e '\<insw\>' --or \
	-e '\<insl\>' --or \
	-e '\<outsb\>' --or \
	-e '\<outsw\>' --or \
	-e '\<outsl\>' --or \
	-e '\<insb_p\>' --or \
	-e '\<insw_p\>' --or \
	-e '\<insl_p\>' --or \
	-e '\<outsb_p\>' --or \
	-e '\<outsw_p\>' --or \
	-e '\<outsl_p\>' --or \
	-e '\<ioread8\>' --or \
	-e '\<ioread16\>' --or \
	-e '\<ioread32\>' --or \
	-e '\<ioread64\>' --or \
	-e '\<iowrite8\>' --or \
	-e '\<iowrite16\>' --or \
	-e '\<iowrite32\>' --or \
	-e '\<iowrite64\>' --or \
	-e '\<ioread16be\>' --or \
	-e '\<ioread32be\>' --or \
	-e '\<ioread64be\>' --or \
	-e '\<iowrite16be\>' --or \
	-e '\<iowrite32be\>' --or \
	-e '\<iowrite64be\>' --or \
	-e '\<ioread8_rep\>' --or \
	-e '\<ioread16_rep\>' --or \
	-e '\<ioread32_rep\>' --or \
	-e '\<ioread64_rep\>' --or \
	-e '\<iowrite8_rep\>' --or \
	-e '\<iowrite16_rep\>' --or \
	-e '\<iowrite32_rep\>' --or \
	-e '\<iowrite64_rep\>' --or \
	-e '\<__io_virt\>' --or \
	-e '\<pci_iounmap\>' --or \
	-e '\<virt_to_phys\>' --or \
	-e '\<phys_to_virt\>' --or \
	-e '\<ioremap_uc\>' --or \
	-e '\<ioremap\>' --or \
	-e '\<__ioremap\>' --or \
	-e '\<iounmap\>' --or \
	-e '\<ioremap\>' --or \
	-e '\<ioremap_nocache\>' --or \
	-e '\<ioremap_uc\>' --or \
	-e '\<ioremap_wc\>' --or \
	-e '\<ioremap_wc\>' --or \
	-e '\<ioremap_wt\>' --or \
	-e '\<ioport_map\>' --or \
	-e '\<ioport_unmap\>' --or \
	-e '\<ioport_map\>' --or \
	-e '\<ioport_unmap\>' --or \
	-e '\<xlate_dev_kmem_ptr\>' --or \
	-e '\<xlate_dev_mem_ptr\>' --or \
	-e '\<unxlate_dev_mem_ptr\>' --or \
	-e '\<virt_to_bus\>' --or \
	-e '\<bus_to_virt\>' --or \
	-e '\<memset_io\>' --or \
	-e '\<memcpy_fromio\>' --or \
	-e '\<memcpy_toio\>'

I also reordered a couple includes when they weren't alphabetical and
removed clk.h from kona, replacing it with clk-provider.h because
that driver doesn't use clk consumer APIs.
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Cc: Chen-Yu Tsai <wens@csie.org>
Acked-by: NMaxime Ripard <maxime.ripard@bootlin.com>
Acked-by: NTero Kristo <t-kristo@ti.com>
Acked-by: NSekhar Nori <nsekhar@ti.com>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: NMark Brown <broonie@kernel.org>
Cc: Chris Zankel <chris@zankel.net>
Acked-by: NMax Filippov <jcmvbkbc@gmail.com>
Acked-by: NJohn Crispin <john@phrozen.org>
Acked-by: NHeiko Stuebner <heiko@sntech.de>
Signed-off-by: NStephen Boyd <sboyd@kernel.org>
      62e59c4e
    • D
      Add wait_var_event_interruptible() · a49294ea
      由 David Howells 提交于 
      Add wait_var_event_interruptible() to allow interruptible waits for events.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
      a49294ea
    • D
      dns_resolver: Allow used keys to be invalidated · d0660f0b
      由 David Howells 提交于 
      Allow used DNS resolver keys to be invalidated after use if the caller is
doing its own caching of the results.  This reduces the amount of resources
required.

Fix AFS to invalidate DNS results to kill off permanent failure records
that get lodged in the resolver keyring and prevent future lookups from
happening.

Fixes: 0a5143f2 ("afs: Implement VL server rotation")
Signed-off-by: NDavid Howells <dhowells@redhat.com>
      d0660f0b
  11. 15 5月, 2019 29 次提交