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A cgroup can consume resources even after being deleted by a user.
For example, writing back dirty pages should be accounted and
limited, despite the corresponding cgroup might contain no processes
and being deleted by a user.
In the current implementation a cgroup can remain in such "dying" state
for an undefined amount of time. For instance, if a memory cgroup
contains a pge, mlocked by a process belonging to an other cgroup.
Although the lifecycle of a dying cgroup is out of user's control,
it's important to have some insight of what's going on under the hood.
In particular, it's handy to have a counter which will allow
to detect css leaks.
To solve this problem, add a cgroup.stat interface to
the base cgroup control files with the following metrics:
nr_descendants total number of visible descendant cgroups
nr_dying_descendants total number of dying descendant cgroups
Signed-off-by: Roman Gushchin <guro@fb.com>
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: kernel-team@fb.com
Cc: cgroups@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
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Creating cgroup hierearchies of unreasonable size can affect
overall system performance. A user might want to limit the
size of cgroup hierarchy. This is especially important if a user
is delegating some cgroup sub-tree.
To address this issue, introduce an ability to control
the size of cgroup hierarchy.
The cgroup.max.descendants control file allows to set the maximum
allowed number of descendant cgroups.
The cgroup.max.depth file controls the maximum depth of the cgroup
tree. Both are single value r/w files, with "max" default value.
The control files exist on each hierarchy level (including root).
When a new cgroup is created, we check the total descendants
and depth limits on each level, and if none of them are exceeded,
a new cgroup is created.
Only alive cgroups are counted, removed (dying) cgroups are
ignored.
Signed-off-by: Roman Gushchin <guro@fb.com>
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: kernel-team@fb.com
Cc: cgroups@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
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Keep track of the number of online and dying descent cgroups.
This data will be used later to add an ability to control cgroup
hierarchy (limit the depth and the number of descent cgroups)
and display hierarchy stats.
Signed-off-by: Roman Gushchin <guro@fb.com>
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: kernel-team@fb.com
Cc: cgroups@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
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Explain cgroup_enable_threaded() and note that the function can never
be called on the root cgroup.
Signed-off-by: Tejun Heo <tj@kernel.org>
Suggested-by: Waiman Long <longman@redhat.com>
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cgroup_enable_threaded() checks that the cgroup doesn't have any tasks
or children and fails the operation if so. This test is unnecessary
because the first part is already checked by
cgroup_can_be_thread_root() and the latter is unnecessary. The latter
actually cause a behavioral oddity. Please consider the following
hierarchy. All cgroups are domains.
A
/ \
B C
\
D
If B is made threaded, C and D becomes invalid domains. Due to the no
children restriction, threaded mode can't be enabled on C. For C and
D, the only thing the user can do is removal.
There is no reason for this restriction. Remove it.
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Update debug controller so that it prints out debug info about thread
mode.
1) The relationship between proc_cset and threaded_csets are displayed.
2) The status of being a thread root or threaded cgroup is displayed.
This patch is extracted from Waiman's larger patch.
v2: - Removed [thread root] / [threaded] from debug.cgroup_css_links
file as the same information is available from cgroup.type.
Suggested by Waiman.
- Threaded marking is moved to the previous patch.
Patch-originally-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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This patch implements cgroup v2 thread support. The goal of the
thread mode is supporting hierarchical accounting and control at
thread granularity while staying inside the resource domain model
which allows coordination across different resource controllers and
handling of anonymous resource consumptions.
A cgroup is always created as a domain and can be made threaded by
writing to the "cgroup.type" file. When a cgroup becomes threaded, it
becomes a member of a threaded subtree which is anchored at the
closest ancestor which isn't threaded.
The threads of the processes which are in a threaded subtree can be
placed anywhere without being restricted by process granularity or
no-internal-process constraint. Note that the threads aren't allowed
to escape to a different threaded subtree. To be used inside a
threaded subtree, a controller should explicitly support threaded mode
and be able to handle internal competition in the way which is
appropriate for the resource.
The root of a threaded subtree, the nearest ancestor which isn't
threaded, is called the threaded domain and serves as the resource
domain for the whole subtree. This is the last cgroup where domain
controllers are operational and where all the domain-level resource
consumptions in the subtree are accounted. This allows threaded
controllers to operate at thread granularity when requested while
staying inside the scope of system-level resource distribution.
As the root cgroup is exempt from the no-internal-process constraint,
it can serve as both a threaded domain and a parent to normal cgroups,
so, unlike non-root cgroups, the root cgroup can have both domain and
threaded children.
Internally, in a threaded subtree, each css_set has its ->dom_cset
pointing to a matching css_set which belongs to the threaded domain.
This ensures that thread root level cgroup_subsys_state for all
threaded controllers are readily accessible for domain-level
operations.
This patch enables threaded mode for the pids and perf_events
controllers. Neither has to worry about domain-level resource
consumptions and it's enough to simply set the flag.
For more details on the interface and behavior of the thread mode,
please refer to the section 2-2-2 in Documentation/cgroup-v2.txt added
by this patch.
v5: - Dropped silly no-op ->dom_cgrp init from cgroup_create().
Spotted by Waiman.
- Documentation updated as suggested by Waiman.
- cgroup.type content slightly reformatted.
- Mark the debug controller threaded.
v4: - Updated to the general idea of marking specific cgroups
domain/threaded as suggested by PeterZ.
v3: - Dropped "join" and always make mixed children join the parent's
threaded subtree.
v2: - After discussions with Waiman, support for mixed thread mode is
added. This should address the issue that Peter pointed out
where any nesting should be avoided for thread subtrees while
coexisting with other domain cgroups.
- Enabling / disabling thread mode now piggy backs on the existing
control mask update mechanism.
- Bug fixes and cleanup.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
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cgroup v2 is in the process of growing thread granularity support.
Once thread mode is enabled, the root cgroup of the subtree serves as
the dom_cgrp to which the processes of the subtree conceptually belong
and domain-level resource consumptions not tied to any specific task
are charged. In the subtree, threads won't be subject to process
granularity or no-internal-task constraint and can be distributed
arbitrarily across the subtree.
This patch implements a new task iterator flag CSS_TASK_ITER_THREADED,
which, when used on a dom_cgrp, makes the iteration include the tasks
on all the associated threaded css_sets. "cgroup.procs" read path is
updated to use it so that reading the file on a proc_cgrp lists all
processes. This will also be used by controller implementations which
need to walk processes or tasks at the resource domain level.
Task iteration is implemented nested in css_set iteration. If
CSS_TASK_ITER_THREADED is specified, after walking tasks of each
!threaded css_set, all the associated threaded css_sets are visited
before moving onto the next !threaded css_set.
v2: ->cur_pcset renamed to ->cur_dcset. Updated for the new
enable-threaded-per-cgroup behavior.
Signed-off-by: Tejun Heo <tj@kernel.org>
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cgroup v2 is in the process of growing thread granularity support. A
threaded subtree is composed of a thread root and threaded cgroups
which are proper members of the subtree.
The root cgroup of the subtree serves as the domain cgroup to which
the processes (as opposed to threads / tasks) of the subtree
conceptually belong and domain-level resource consumptions not tied to
any specific task are charged. Inside the subtree, threads won't be
subject to process granularity or no-internal-task constraint and can
be distributed arbitrarily across the subtree.
This patch introduces cgroup->dom_cgrp along with threaded css_set
handling.
* cgroup->dom_cgrp points to self for normal and thread roots. For
proper thread subtree members, points to the dom_cgrp (the thread
root).
* css_set->dom_cset points to self if for normal and thread roots. If
threaded, points to the css_set which belongs to the cgrp->dom_cgrp.
The dom_cgrp serves as the resource domain and keeps the matching
csses available. The dom_cset holds those csses and makes them
easily accessible.
* All threaded csets are linked on their dom_csets to enable iteration
of all threaded tasks.
* cgroup->nr_threaded_children keeps track of the number of threaded
children.
This patch adds the above but doesn't actually use them yet. The
following patches will build on top.
v4: ->nr_threaded_children added.
v3: ->proc_cgrp/cset renamed to ->dom_cgrp/cset. Updated for the new
enable-threaded-per-cgroup behavior.
v2: Added cgroup_is_threaded() helper.
Signed-off-by: Tejun Heo <tj@kernel.org>
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css_task_iter currently always walks all tasks. With the scheduled
cgroup v2 thread support, the iterator would need to handle multiple
types of iteration. As a preparation, add @flags to
css_task_iter_start() and implement CSS_TASK_ITER_PROCS. If the flag
is not specified, it walks all tasks as before. When asserted, the
iterator only walks the group leaders.
For now, the only user of the flag is cgroup v2 "cgroup.procs" file
which no longer needs to skip non-leader tasks in cgroup_procs_next().
Note that cgroup v1 "cgroup.procs" can't use the group leader walk as
v1 "cgroup.procs" doesn't mean "list all thread group leaders in the
cgroup" but "list all thread group id's with any threads in the
cgroup".
While at it, update cgroup_procs_show() to use task_pid_vnr() instead
of task_tgid_vnr(). As the iteration guarantees that the function
only sees group leaders, this doesn't change the output and will allow
sharing the function for thread iteration.
Signed-off-by: Tejun Heo <tj@kernel.org>
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Currently, writes "cgroup.procs" and "cgroup.tasks" files are all
handled by __cgroup_procs_write() on both v1 and v2. This patch
reoragnizes the write path so that there are common helper functions
that different write paths use.
While this somewhat increases LOC, the different paths are no longer
intertwined and each path has more flexibility to implement different
behaviors which will be necessary for the planned v2 thread support.
v3: - Restructured so that cgroup_procs_write_permission() takes
@src_cgrp and @dst_cgrp.
v2: - Rolled in Waiman's task reference count fix.
- Updated on top of nsdelegate changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
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Implement trivial cgroup_has_tasks() which tests whether
cgrp->nr_populated_csets is zero and replace the explicit local
populated test in cgroup_subtree_control(). This simplifies the code
and cgroup_has_tasks() will be used in more places later.
Signed-off-by: Tejun Heo <tj@kernel.org>
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cgrp->populated_cnt counts both local (the cgroup's populated
css_sets) and subtree proper (populated children) so that it's only
zero when the whole subtree, including self, is empty.
This patch splits the counter into two so that local and children
populated states are tracked separately. It allows finer-grained
tests on the state of the hierarchy which will be used to replace
css_set walking local populated test.
Signed-off-by: Tejun Heo <tj@kernel.org>
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Signed-off-by: Tejun Heo <tj@kernel.org>
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576dd464505f ("cgroup: drop the matching uid requirement on migration
for cgroup v2") dropped the uid match requirement from "cgroup.procs"
perm check but forgot to update the matching entry in the
documentation. Update it.
Signed-off-by: Tejun Heo <tj@kernel.org>
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Avoid the READ_ONCE in commit 4a072c71f49b ("random: silence compiler
warnings and fix race") if we can leave the function after
arch_get_random_XXX().
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Unfortunately, on some models of some architectures getting a fully
seeded CRNG is extremely difficult, and so this can result in dmesg
getting spammed for a surprisingly long time. This is really bad from
a security perspective, and so architecture maintainers really need to
do what they can to get the CRNG seeded sooner after the system is
booted. However, users can't do anything actionble to address this,
and spamming the kernel messages log will only just annoy people.
For developers who want to work on improving this situation,
CONFIG_WARN_UNSEEDED_RANDOM has been renamed to
CONFIG_WARN_ALL_UNSEEDED_RANDOM. By default the kernel will always
print the first use of unseeded randomness. This way, hopefully the
security obsessed will be happy that there is _some_ indication when
the kernel boots there may be a potential issue with that architecture
or subarchitecture. To see all uses of unseeded randomness,
developers can enable CONFIG_WARN_ALL_UNSEEDED_RANDOM.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Using strscpy was wrong because FORTIFY_SOURCE is passing the maximum
possible size of the outermost object, but strscpy defines the count
parameter as the exact buffer size, so this could copy past the end of
the source. This would still be wrong with the planned usage of
__builtin_object_size(p, 1) for intra-object overflow checks since it's
the maximum possible size of the specified object with no guarantee of
it being that large.
Reuse of the fortified functions like this currently makes the runtime
error reporting less precise but that can be improved later on.
Noticed by Dave Jones and KASAN.
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reported-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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If we reach the limit of modprobe_limit threads running the next
request_module() call will fail. The original reason for adding a kill
was to do away with possible issues with in old circumstances which would
create a recursive series of request_module() calls.
We can do better than just be super aggressive and reject calls once we've
reached the limit by simply making pending callers wait until the
threshold has been reduced, and then throttling them in, one by one.
This throttling enables requests over the kmod concurrent limit to be
processed once a pending request completes. Only the first item queued up
to wait is woken up. The assumption here is once a task is woken it will
have no other option to also kick the queue to check if there are more
pending tasks -- regardless of whether or not it was successful.
By throttling and processing only max kmod concurrent tasks we ensure we
avoid unexpected fatal request_module() calls, and we keep memory
consumption on module loading to a minimum.
With x86_64 qemu, with 4 cores, 4 GiB of RAM it takes the following run
time to run both tests:
time ./kmod.sh -t 0008
real 0m16.366s
user 0m0.883s
sys 0m8.916s
time ./kmod.sh -t 0009
real 0m50.803s
user 0m0.791s
sys 0m9.852s
Link: http://lkml.kernel.org/r/20170628223155.26472-4-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michal Marek <mmarek@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This adds a new stress test driver for kmod: the kernel module loader.
The new stress test driver, test_kmod, is only enabled as a module right
now. It should be possible to load this as built-in and load tests
early (refer to the force_init_test module parameter), however since a
lot of test can get a system out of memory fast we leave this disabled
for now.
Using a system with 1024 MiB of RAM can *easily* get your kernel OOM
fast with this test driver.
The test_kmod driver exposes API knobs for us to fine tune simple
request_module() and get_fs_type() calls. Since these API calls only
allow each one parameter a test driver for these is rather simple.
Other factors that can help out test driver though are the number of
calls we issue and knowing current limitations of each. This exposes
configuration as much as possible through userspace to be able to build
tests directly from userspace.
Since it allows multiple misc devices its will eventually (once we add a
knob to let us create new devices at will) also be possible to perform
more tests in parallel, provided you have enough memory.
We only enable tests we know work as of right now.
Demo screenshots:
# tools/testing/selftests/kmod/kmod.sh
kmod_test_0001_driver: OK! - loading kmod test
kmod_test_0001_driver: OK! - Return value: 256 (MODULE_NOT_FOUND), expected MODULE_NOT_FOUND
kmod_test_0001_fs: OK! - loading kmod test
kmod_test_0001_fs: OK! - Return value: -22 (-EINVAL), expected -EINVAL
kmod_test_0002_driver: OK! - loading kmod test
kmod_test_0002_driver: OK! - Return value: 256 (MODULE_NOT_FOUND), expected MODULE_NOT_FOUND
kmod_test_0002_fs: OK! - loading kmod test
kmod_test_0002_fs: OK! - Return value: -22 (-EINVAL), expected -EINVAL
kmod_test_0003: OK! - loading kmod test
kmod_test_0003: OK! - Return value: 0 (SUCCESS), expected SUCCESS
kmod_test_0004: OK! - loading kmod test
kmod_test_0004: OK! - Return value: 0 (SUCCESS), expected SUCCESS
kmod_test_0005: OK! - loading kmod test
kmod_test_0005: OK! - Return value: 0 (SUCCESS), expected SUCCESS
kmod_test_0006: OK! - loading kmod test
kmod_test_0006: OK! - Return value: 0 (SUCCESS), expected SUCCESS
kmod_test_0005: OK! - loading kmod test
kmod_test_0005: OK! - Return value: 0 (SUCCESS), expected SUCCESS
kmod_test_0006: OK! - loading kmod test
kmod_test_0006: OK! - Return value: 0 (SUCCESS), expected SUCCESS
XXX: add test restult for 0007
Test completed
You can also request for specific tests:
# tools/testing/selftests/kmod/kmod.sh -t 0001
kmod_test_0001_driver: OK! - loading kmod test
kmod_test_0001_driver: OK! - Return value: 256 (MODULE_NOT_FOUND), expected MODULE_NOT_FOUND
kmod_test_0001_fs: OK! - loading kmod test
kmod_test_0001_fs: OK! - Return value: -22 (-EINVAL), expected -EINVAL
Test completed
Lastly, the current available number of tests:
# tools/testing/selftests/kmod/kmod.sh --help
Usage: tools/testing/selftests/kmod/kmod.sh [ -t <4-number-digit> ]
Valid tests: 0001-0009
0001 - Simple test - 1 thread for empty string
0002 - Simple test - 1 thread for modules/filesystems that do not exist
0003 - Simple test - 1 thread for get_fs_type() only
0004 - Simple test - 2 threads for get_fs_type() only
0005 - multithreaded tests with default setup - request_module() only
0006 - multithreaded tests with default setup - get_fs_type() only
0007 - multithreaded tests with default setup test request_module() and get_fs_type()
0008 - multithreaded - push kmod_concurrent over max_modprobes for request_module()
0009 - multithreaded - push kmod_concurrent over max_modprobes for get_fs_type()
The following test cases currently fail, as such they are not currently
enabled by default:
# tools/testing/selftests/kmod/kmod.sh -t 0008
# tools/testing/selftests/kmod/kmod.sh -t 0009
To be sure to run them as intended please unload both of the modules:
o test_module
o xfs
And ensure they are not loaded on your system prior to testing them. If
you use these paritions for your rootfs you can change the default test
driver used for get_fs_type() by exporting it into your environment. For
example of other test defaults you can override refer to kmod.sh
allow_user_defaults().
Behind the scenes this is how we fine tune at a test case prior to
hitting a trigger to run it:
cat /sys/devices/virtual/misc/test_kmod0/config
echo -n "2" > /sys/devices/virtual/misc/test_kmod0/config_test_case
echo -n "ext4" > /sys/devices/virtual/misc/test_kmod0/config_test_fs
echo -n "80" > /sys/devices/virtual/misc/test_kmod0/config_num_threads
cat /sys/devices/virtual/misc/test_kmod0/config
echo -n "1" > /sys/devices/virtual/misc/test_kmod0/config_num_threads
Finally to trigger:
echo -n "1" > /sys/devices/virtual/misc/test_kmod0/trigger_config
The kmod.sh script uses the above constructs to build different test cases.
A bit of interpretation of the current failures follows, first two
premises:
a) When request_module() is used userspace figures out an optimized
version of module order for us. Once it finds the modules it needs, as
per depmod symbol dep map, it will finit_module() the respective
modules which are needed for the original request_module() request.
b) We have an optimization in place whereby if a kernel uses
request_module() on a module already loaded we never bother userspace
as the module already is loaded. This is all handled by kernel/kmod.c.
A few things to consider to help identify root causes of issues:
0) kmod 19 has a broken heuristic for modules being assumed to be
built-in to your kernel and will return 0 even though request_module()
failed. Upgrade to a newer version of kmod.
1) A get_fs_type() call for "xfs" will request_module() for "fs-xfs",
not for "xfs". The optimization in kernel described in b) fails to
catch if we have a lot of consecutive get_fs_type() calls. The reason
is the optimization in place does not look for aliases. This means two
consecutive get_fs_type() calls will bump kmod_concurrent, whereas
request_module() will not.
This one explanation why test case 0009 fails at least once for
get_fs_type().
2) If a module fails to load --- for whatever reason (kmod_concurrent
limit reached, file not yet present due to rootfs switch, out of
memory) we have a period of time during which module request for the
same name either with request_module() or get_fs_type() will *also*
fail to load even if the file for the module is ready.
This explains why *multiple* NULLs are possible on test 0009.
3) finit_module() consumes quite a bit of memory.
4) Filesystems typically also have more dependent modules than other
modules, its important to note though that even though a get_fs_type()
call does not incur additional kmod_concurrent bumps, since userspace
loads dependencies it finds it needs via finit_module_fd(), it *will*
take much more memory to load a module with a lot of dependencies.
Because of 3) and 4) we will easily run into out of memory failures with
certain tests. For instance test 0006 fails on qemu with 1024 MiB of RAM.
It panics a box after reaping all userspace processes and still not
having enough memory to reap.
[arnd@arndb.de: add dependencies for test module]
Link: http://lkml.kernel.org/r/20170630154834.3689272-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20170628223155.26472-3-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michal Marek <mmarek@suse.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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As suggested by Jessica, I've been actively working on kmod, so might as
well reflect its maintained status.
Changes are expected to go through akpm's tree.
Link: http://lkml.kernel.org/r/20170628223155.26472-2-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Suggested-by: Jessica Yu <jeyu@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michal Marek <mmarek@suse.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The arch uses a verbatim copy of the asm-generic version and does not
add any own implementations to the header, so use asm-generic/fb.h
instead of duplicating code.
Link: http://lkml.kernel.org/r/20170517083545.2115-1-tklauser@distanz.ch
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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fail-nth interface is only created in /proc/self/task/<current-tid>/.
This change also adds it in /proc/<pid>/.
This makes shell based tool a bit simpler.
$ bash -c "builtin echo 100 > /proc/self/fail-nth && exec ls /"
Link: http://lkml.kernel.org/r/1491490561-10485-6-git-send-email-akinobu.mita@gmail.com
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The fail-nth file is created with 0666 and the access is permitted if
and only if the task is current.
This file is owned by the currnet user. So we can create it with 0644
and allow the owner to write it. This enables to watch the status of
task->fail_nth from another processes.
[akinobu.mita@gmail.com: don't convert unsigned type value as signed int]
Link: http://lkml.kernel.org/r/1492444483-9239-1-git-send-email-akinobu.mita@gmail.com
[akinobu.mita@gmail.com: avoid unwanted data race to task->fail_nth]
Link: http://lkml.kernel.org/r/1499962492-8931-1-git-send-email-akinobu.mita@gmail.com
Link: http://lkml.kernel.org/r/1491490561-10485-5-git-send-email-akinobu.mita@gmail.com
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The read interface for fail-nth looks a bit odd. Read from this file
returns "NYYYY..." or "YYYYY..." (this makes me surprise when cat this
file). Because there is no EOF condition. The first character
indicates current->fail_nth is zero or not, and then current->fail_nth
is reset to zero.
Just returning task->fail_nth value is more natural to understand.
Link: http://lkml.kernel.org/r/1491490561-10485-4-git-send-email-akinobu.mita@gmail.com
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The value written to fail-nth file is parsed as 0-based. Parsing as
one-based is more natural to understand and it enables to cancel the
previous setup by simply writing '0'.
This change also converts task->fail_nth from signed to unsigned int.
Link: http://lkml.kernel.org/r/1491490561-10485-3-git-send-email-akinobu.mita@gmail.com
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Automatically detect the number base to use when writing to fail-nth
file instead of always parsing as a decimal number.
Link: http://lkml.kernel.org/r/1491490561-10485-2-git-send-email-akinobu.mita@gmail.com
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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After commit 73ce0511c436 ("kernel/watchdog.c: move hardlockup
detector to separate file"), 'NMI watchdog' is inappropriate in
kernel/watchdog.c, using 'watchdog' only.
Link: http://lkml.kernel.org/r/1499928642-48983-1-git-send-email-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Babu Moger <babu.moger@oracle.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Update the location of the befs git tree and my email address.
Link: http://lkml.kernel.org/r/20170709110012.2991-1-luisbg@kernel.org
Signed-off-by: Luis de Bethencourt <luisbg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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atomic64_inc_not_zero() returns a "truth value" which in C is
traditionally an int. That means callers are likely to expect the
result will fit in an int.
If an implementation returns a "true" value which does not fit in an
int, then there's a possibility that callers will truncate it when they
store it in an int.
In fact this happened in practice, see commit 966d2b04e070
("percpu-refcount: fix reference leak during percpu-atomic transition").
So add a test that the result fits in an int, even when the input
doesn't. This catches the case where an implementation just passes the
non-zero input value out as the result.
Link: http://lkml.kernel.org/r/1499775133-1231-1-git-send-email-mpe@ellerman.id.au
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Douglas Miller <dougmill@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Jörn Engel noticed that the expand_upwards() function might not return
-ENOMEM in case the requested address is (unsigned long)-PAGE_SIZE and
if the architecture didn't defined TASK_SIZE as multiple of PAGE_SIZE.
Affected architectures are arm, frv, m68k, blackfin, h8300 and xtensa
which all define TASK_SIZE as 0xffffffff, but since none of those have
an upwards-growing stack we currently have no actual issue.
Nevertheless let's fix this just in case any of the architectures with
an upward-growing stack (currently parisc, metag and partly ia64) define
TASK_SIZE similar.
Link: http://lkml.kernel.org/r/20170702192452.GA11868@p100.box
Fixes: bd726c90b6b8 ("Allow stack to grow up to address space limit")
Signed-off-by: Helge Deller <deller@gmx.de>
Reported-by: Jörn Engel <joern@purestorage.com>
Cc: Hugh Dickins <hughd@google.com>
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>
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We developed RENAME_EXCHANGE and UBIFS_FLG_DOUBLE_HASH more or less in
parallel and this case was forgotten. :-(
Cc: stable@vger.kernel.org
Fixes: d63d61c16972 ("ubifs: Implement UBIFS_FLG_DOUBLE_HASH")
Signed-off-by: Richard Weinberger <richard@nod.at>
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The inode is not locked in init_xattrs when creating a new inode.
Without this patch, there will occurs assert when booting or creating
a new file, if the kernel config CONFIG_SECURITY_SMACK is enabled.
Log likes:
UBIFS assert failed in ubifs_xattr_set at 298 (pid 1156)
CPU: 1 PID: 1156 Comm: ldconfig Tainted: G S 4.12.0-rc1-207440-g1e70b02 #2
Hardware name: MediaTek MT2712 evaluation board (DT)
Call trace:
[<ffff000008088538>] dump_backtrace+0x0/0x238
[<ffff000008088834>] show_stack+0x14/0x20
[<ffff0000083d98d4>] dump_stack+0x9c/0xc0
[<ffff00000835d524>] ubifs_xattr_set+0x374/0x5e0
[<ffff00000835d7ec>] init_xattrs+0x5c/0xb8
[<ffff000008385788>] security_inode_init_security+0x110/0x190
[<ffff00000835e058>] ubifs_init_security+0x30/0x68
[<ffff00000833ada0>] ubifs_mkdir+0x100/0x200
[<ffff00000820669c>] vfs_mkdir+0x11c/0x1b8
[<ffff00000820b73c>] SyS_mkdirat+0x74/0xd0
[<ffff000008082f8c>] __sys_trace_return+0x0/0x4
Signed-off-by: Xiaolei Li <xiaolei.li@mediatek.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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When UBIFS prepares data structures which will be written to the MTD it
ensues that their lengths are multiple of 8. Since it uses kmalloc() the
padded bytes are left uninitialized and we leak a few bytes of kernel
memory to the MTD.
To make sure that all bytes are initialized, let's switch to kzalloc().
Kzalloc() is fine in this case because the buffers are not huge and in
the IO path the performance bottleneck is anyway the MTD.
Cc: stable@vger.kernel.org
Fixes: 1e51764a3c2a ("UBIFS: add new flash file system")
Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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In low memory situations, page allocations for bulk read
can kill applications for reclaiming memory, and print an
failure message when allocations are failed.
Because bulk read is just an optimization, we don't have
to do these and can stop page allocations.
Though this siutation happens rarely, add __GFP_NORETRY
to prevent from excessive memory reclaim and killing
applications, and __GFP_WARN to suppress this failure
message.
For this, Use readahead_gfp_mask for gfp flags when
allocating pages.
Signed-off-by: Hyunchul Lee <cheol.lee@lge.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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When remounting with the no_bulk_read option,
there is a problem accessing the "bulk_read buffer(bu.buf)"
which has already been freed.
If the bulk_read option is enabled,
ubifs_tnc_bulk_read uses the pre-allocated bu.buf.
While bu.buf is being used by ubifs_tnc_bulk_read,
remounting with no_bulk_read frees bu.buf.
So I added code to check the use of "bu.buf" to avoid this situation.
------
I tested as follows(kernel v3.18) :
Use the script to repeat "no_bulk_read <-> bulk_read"
remount.sh
#!/bin/sh
while true do;
mount -o remount,no_bulk_read ${MOUNT_POINT};
sleep 1;
mount -o remount,bulk_read ${MOUNT_POINT};
sleep 1;
done
Perform read operation
cat ${MOUNT_POINT}/* > /dev/null
The problem is reproduced immediately.
[ 234.256845][kernel.0]Internal error: Oops: 17 [#1] PREEMPT ARM
[ 234.258557][kernel.0]CPU: 0 PID: 2752 Comm: cat Tainted: G W O 3.18.31+ #51
[ 234.259531][kernel.0]task: cbff8580 ti: cbd66000 task.ti: cbd66000
[ 234.260306][kernel.0]PC is at validate_data_node+0x10/0x264
[ 234.260994][kernel.0]LR is at ubifs_tnc_bulk_read+0x388/0x3ec
[ 234.261712][kernel.0]pc : [<c01d98fc>] lr : [<c01dc300>] psr: 80000013
[ 234.261712][kernel.0]sp : cbd67ba0 ip : 00000001 fp : 00000000
[ 234.263337][kernel.0]r10: cd3e0260 r9 : c0df2008 r8 : 00000000
[ 234.264087][kernel.0]r7 : cd3e0000 r6 : 00000000 r5 : cd3e0278 r4 : cd3e0000
[ 234.264999][kernel.0]r3 : 00000003 r2 : cd3e0280 r1 : 00000000 r0 : cd3e0000
[ 234.265910][kernel.0]Flags: Nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
[ 234.266896][kernel.0]Control: 10c53c7d Table: 8c40c059 DAC: 00000015
[ 234.267711][kernel.0]Process cat (pid: 2752, stack limit = 0xcbd66400)
[ 234.268525][kernel.0]Stack: (0xcbd67ba0 to 0xcbd68000)
[ 234.269169][kernel.0]7ba0: cd7c3940 c03d8650 0001bfe0 00002ab2 00000000 cbd67c5c cbd67c58 0001bfe0
[ 234.270287][kernel.0]7bc0: cd3e0000 00002ab2 0001bfe0 00000014 cbd66000 cd3e0260 00000000 c01d6660
[ 234.271403][kernel.0]7be0: 00002ab2 00000000 c82a5800 ffffffff cd3e0298 cd3e0278 00000000 cd3e0000
[ 234.272520][kernel.0]7c00: 00000000 00000000 cd3e0260 c01dc300 00002ab2 00000000 60000013 d663affa
[ 234.273639][kernel.0]7c20: cd3e01f0 cd3e01f0 60000013 c09397ec 00000000 cd3e0278 00002ab2 00000000
[ 234.274755][kernel.0]7c40: cd3e0000 c01dbf48 00000014 00000003 00000160 00000015 00000004 d663affa
[ 234.275874][kernel.0]7c60: ccdaa978 cd3e0278 cd3e0000 cf32a5f4 ccdaa820 00000044 cbd66000 cd3e0260
[ 234.276992][kernel.0]7c80: 00000003 c01cec84 ccdaa8dc cbd67cc4 cbd67ec0 00000010 ccdaa978 00000000
[ 234.278108][kernel.0]7ca0: 0000015e ccdaa8dc 00000000 00000000 cf32a5d0 00000000 0000015f ccdaa8dc
[ 234.279228][kernel.0]7cc0: 00000000 c8488300 0009e5a4 0000000e cbd66000 0000015e cf32a5f4 c0113c04
[ 234.280346][kernel.0]7ce0: 0000009f 0000003c c00098c4 ffffffff 00001000 00000000 000000ad 00000010
[ 234.281463][kernel.0]7d00: 00000038 cd68f580 00000150 c8488360 00000000 cbd67d30 cbd67d70 0000000e
[ 234.282579][kernel.0]7d20: 00000010 00000000 c0951874 c0112a9c cf379b60 cf379b84 cf379890 cf3798b4
[ 234.283699][kernel.0]7d40: cf379578 cf37959c cf379380 cf3793a4 cf3790b0 cf3790d4 cf378fd8 cf378ffc
[ 234.284814][kernel.0]7d60: cf378f48 cf378f6c cf32a5f4 cf32a5d0 00000000 00001000 00000018 00000000
[ 234.285932][kernel.0]7d80: 00001000 c0050da4 00000000 00001000 cec04c00 00000000 00001000 c0e11328
[ 234.287049][kernel.0]7da0: 00000000 00001000 cbd66000 00000000 00001000 c0012a60 00000000 00001000
[ 234.288166][kernel.0]7dc0: cbd67dd4 00000000 00001000 80000013 00000000 00001000 cd68f580 00000000
[ 234.289285][kernel.0]7de0: 00001000 c915d600 00000000 00001000 cbd67e48 00000000 00001000 00000018
[ 234.290402][kernel.0]7e00: 00000000 00001000 00000000 00000000 00001000 c915d768 c915d768 c0113550
[ 234.291522][kernel.0]7e20: cd68f580 cbd67e48 cd68f580 cb6713c0 00010000 000ac5a4 00000000 001fc5a4
[ 234.292637][kernel.0]7e40: 00000000 c8488300 cbd67ec0 00eb0000 cd68f580 c0113ee4 00000000 cbd67ec0
[ 234.293754][kernel.0]7e60: cd68f580 c8488300 cbd67ec0 00eb0000 cd68f580 00150000 c8488300 00eb0000
[ 234.294874][kernel.0]7e80: 00010000 c0112fd0 00000000 cbd67ec0 cd68f580 00150000 00000000 cd68f580
[ 234.295991][kernel.0]7ea0: cbd67ef0 c011308c 00000000 00000002 cd768850 00010000 00000000 c01133fc
[ 234.297110][kernel.0]7ec0: 00150000 00000000 cbd67f50 00000000 00000000 cb6713c0 01000000 cbd67f48
[ 234.298226][kernel.0]7ee0: cbd67f50 c8488300 00000000 c0113204 00010000 01000000 00000000 cb6713c0
[ 234.299342][kernel.0]7f00: 00150000 00000000 cbd67f50 00000000 00000000 00000000 00000000 00000000
[ 234.300462][kernel.0]7f20: cbd67f50 01000000 01000000 cb6713c0 c8488300 c00ebba8 01000000 00000000
[ 234.301577][kernel.0]7f40: c8488300 cb6713c0 00000000 00000000 00000000 00000000 ccdaa820 00000000
[ 234.302697][kernel.0]7f60: 00000000 01000000 00000003 00000001 cbd66000 00000000 00000001 c00ec678
[ 234.303813][kernel.0]7f80: 00000000 00000200 00000000 01000000 01000000 00000000 00000000 000000ef
[ 234.304933][kernel.0]7fa0: c000e904 c000e780 01000000 00000000 00000001 00000003 00000000 01000000
[ 234.306049][kernel.0]7fc0: 01000000 00000000 00000000 000000ef 00000001 00000003 01000000 00000001
[ 234.307165][kernel.0]7fe0: 00000000 beafb78c 0000ad08 00128d1c 60000010 00000001 00000000 00000000
[ 234.308292][kernel.0][<c01d98fc>] (validate_data_node) from [<c01dc300>] (ubifs_tnc_bulk_read+0x388/0x3ec)
[ 234.309493][kernel.0][<c01dc300>] (ubifs_tnc_bulk_read) from [<c01cec84>] (ubifs_readpage+0x1dc/0x46c)
[ 234.310656][kernel.0][<c01cec84>] (ubifs_readpage) from [<c0113c04>] (__generic_file_splice_read+0x29c/0x4cc)
[ 234.311890][kernel.0][<c0113c04>] (__generic_file_splice_read) from [<c0113ee4>] (generic_file_splice_read+0xb0/0xf4)
[ 234.313214][kernel.0][<c0113ee4>] (generic_file_splice_read) from [<c0112fd0>] (do_splice_to+0x68/0x7c)
[ 234.314386][kernel.0][<c0112fd0>] (do_splice_to) from [<c011308c>] (splice_direct_to_actor+0xa8/0x190)
[ 234.315544][kernel.0][<c011308c>] (splice_direct_to_actor) from [<c0113204>] (do_splice_direct+0x90/0xb8)
[ 234.316741][kernel.0][<c0113204>] (do_splice_direct) from [<c00ebba8>] (do_sendfile+0x17c/0x2b8)
[ 234.317838][kernel.0][<c00ebba8>] (do_sendfile) from [<c00ec678>] (SyS_sendfile64+0xc4/0xcc)
[ 234.318890][kernel.0][<c00ec678>] (SyS_sendfile64) from [<c000e780>] (ret_fast_syscall+0x0/0x38)
[ 234.319983][kernel.0]Code: e92d47f0 e24dd050 e59f9228 e1a04000 (e5d18014)
Signed-off-by: karam.lee <karam.lee@lge.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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A reference to LEB 0 or with length 0 in the TNC
is never correct and could be caused by a memory corruption.
Don't write such a bad index node to the MTD.
Instead fail the commit which will turn UBIFS into read-only mode.
This is less painful than having the bad reference on the MTD
from where UBFIS has no chance to recover.
Signed-off-by: Richard Weinberger <richard@nod.at>
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There currently appears to be no way for userspace to find out the
underlying volume number for a mounted ubifs file system, since ubifs
uses anonymous block devices. The volume name is present in
/proc/mounts but UBI volumes can be renamed after the volume has been
mounted.
To remedy this, show the UBI number and UBI volume number as part of the
options visible under /proc/mounts.
Also, accept and ignore the ubi= vol= options if they are used mounting
(patch from Richard Weinberger).
# mount -t ubifs ubi:baz x
# mount
ubi:baz on /root/x type ubifs (rw,relatime,ubi=0,vol=2)
# ubirename /dev/ubi0 baz bazz
# mount
ubi:baz on /root/x type ubifs (rw,relatime,ubi=0,vol=2)
# ubinfo -d 0 -n 2
Volume ID: 2 (on ubi0)
Type: dynamic
Alignment: 1
Size: 67 LEBs (1063424 bytes, 1.0 MiB)
State: OK
Name: bazz
Character device major/minor: 254:3
Signed-off-by: Rabin Vincent <rabinv@axis.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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statx() can report what flags a file has, expose flags that UBIFS
supports. Especially STATX_ATTR_COMPRESSED and STATX_ATTR_ENCRYPTED
can be interesting for userspace.
Signed-off-by: Richard Weinberger <richard@nod.at>
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We check the length already, no need to check later
again for an empty string.
Signed-off-by: Richard Weinberger <richard@nod.at>
|
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If file names are encrypted we can no longer print them.
That's why we have to change these prints or remove them completely.
Signed-off-by: Richard Weinberger <richard@nod.at>
|
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...to make sure that we don't use it for double hashed lookups
instead of dent_key_init_hash().
Signed-off-by: Richard Weinberger <richard@nod.at>
|
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When removing an encrypted file with a long name and without having
the key we have to be able to locate and remove the directory entry
via a double hash. This corner case was simply forgotten.
Fixes: 528e3d178f25 ("ubifs: Add full hash lookup support")
Reported-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Signed-off-by: Richard Weinberger <richard@nod.at>
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Currently, the function truncate_data_node only updates the
destination data node size if compression is used. For
uncompressed nodes, the old length is incorrectly retained.
This patch makes sure that the length is correctly set when
compression is disabled.
Fixes: 7799953b34d1 ("ubifs: Implement encrypt/decrypt for all IO")
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Signed-off-by: Richard Weinberger <richard@nod.at>
|
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When a new inode is created, we check if the containing folder has a encryption
policy set and inherit that. This should however only be done for regular
files, links and subdirectories. Not for sockes fifos etc.
Fixes: d475a507457b ("ubifs: Add skeleton for fscrypto")
Cc: stable@vger.kernel.org
Signed-off-by: David Gstir <david@sigma-star.at>
Signed-off-by: Richard Weinberger <richard@nod.at>
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in RENAME_WHITEOUT error path, fscrypt_name should be freed.
Signed-off-by: Hyunchul Lee <cheol.lee@lge.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
|
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Assign inode data budget to budget request correctly.
Signed-off-by: Hyunchul Lee <cheol.lee@lge.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
|
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UBIFS handles extended attributes just like files, as consequence of
that, they also have inodes.
Therefore UBIFS does all the inode machinery also for xattrs. Since new
inodes have i_nlink of 1, a file or xattr inode will be evicted
if i_nlink goes down to 0 after an unlink. UBIFS assumes this model also
for xattrs, which is not correct.
One can create a file "foo" with xattr "user.test". By reading
"user.test" an inode will be created, and by deleting "user.test" it
will get evicted later. The assumption breaks if the file "foo", which
hosts the xattrs, will be removed. VFS nor UBIFS does not remove each
xattr via ubifs_xattr_remove(), it just removes the host inode from
the TNC and all underlying xattr nodes too and the inode will remain
in the cache and wastes memory.
To solve this problem, remove xattr inodes from the VFS inode cache in
ubifs_xattr_remove() to make sure that they get evicted.
Fixes: 1e51764a3c2ac05a ("UBIFS: add new flash file system")
Cc: <stable@vger.kernel.org>
Signed-off-by: Richard Weinberger <richard@nod.at>
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This SLAB is only being used in super.c, there is no need to expose
it into the global namespace.
Signed-off-by: Richard Weinberger <richard@nod.at>
|