Merge tag 'v6.6.44' into for/openbmc/dev-6.6

This is the 6.6.44 stable release

cgroup/cpuset: Prevent UAF in proc_cpuset_show()

[ Upstream commit 1be59c97c83ccd67a519d8a49486b3a8a73ca28a ]

An UAF can happen when /proc/cpuset is read as reported in [1].

This can be reproduced

cgroup/cpuset: Prevent UAF in proc_cpuset_show()

[ Upstream commit 1be59c97c83ccd67a519d8a49486b3a8a73ca28a ]

An UAF can happen when /proc/cpuset is read as reported in [1].

This can be reproduced by the following methods:
1.add an mdelay(1000) before acquiring the cgroup_lock In the
cgroup_path_ns function.
2.$cat /proc/<pid>/cpuset repeatly.
3.$mount -t cgroup -o cpuset cpuset /sys/fs/cgroup/cpuset/
$umount /sys/fs/cgroup/cpuset/ repeatly.

The race that cause this bug can be shown as below:

(umount) | (cat /proc/<pid>/cpuset)
css_release | proc_cpuset_show
css_release_work_fn | css = task_get_css(tsk, cpuset_cgrp_id);
css_free_rwork_fn | cgroup_path_ns(css->cgroup, ...);
cgroup_destroy_root | mutex_lock(&cgroup_mutex);
rebind_subsystems |
cgroup_free_root |
| // cgrp was freed, UAF
| cgroup_path_ns_locked(cgrp,..);

When the cpuset is initialized, the root node top_cpuset.css.cgrp
will point to &cgrp_dfl_root.cgrp. In cgroup v1, the mount operation will
allocate cgroup_root, and top_cpuset.css.cgrp will point to the allocated
&cgroup_root.cgrp. When the umount operation is executed,
top_cpuset.css.cgrp will be rebound to &cgrp_dfl_root.cgrp.

The problem is that when rebinding to cgrp_dfl_root, there are cases
where the cgroup_root allocated by setting up the root for cgroup v1
is cached. This could lead to a Use-After-Free (UAF) if it is
subsequently freed. The descendant cgroups of cgroup v1 can only be
freed after the css is released. However, the css of the root will never
be released, yet the cgroup_root should be freed when it is unmounted.
This means that obtaining a reference to the css of the root does
not guarantee that css.cgrp->root will not be freed.

Fix this problem by using rcu_read_lock in proc_cpuset_show().
As cgroup_root is kfree_rcu after commit d23b5c577715
("cgroup: Make operations on the cgroup root_list RCU safe"),
css->cgroup won't be freed during the critical section.
To call cgroup_path_ns_locked, css_set_lock is needed, so it is safe to
replace task_get_css with task_css.

[1] https://syzkaller.appspot.com/bug?extid=9b1ff7be974a403aa4cd

Fixes: a79a908fd2b0 ("cgroup: introduce cgroup namespaces")
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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kernfs: Convert kernfs_path_from_node_locked() from strlcpy() to strscpy()

[ Upstream commit ff6d413b0b59466e5acf2e42f294b1842ae130a1 ]

One of the last remaining users of strlcpy() in the kernel is

kernfs: Convert kernfs_path_from_node_locked() from strlcpy() to strscpy()

[ Upstream commit ff6d413b0b59466e5acf2e42f294b1842ae130a1 ]

One of the last remaining users of strlcpy() in the kernel is
kernfs_path_from_node_locked(), which passes back the problematic "length
we _would_ have copied" return value to indicate truncation. Convert the
chain of all callers to use the negative return value (some of which
already doing this explicitly). All callers were already also checking
for negative return values, so the risk to missed checks looks very low.

In this analysis, it was found that cgroup1_release_agent() actually
didn't handle the "too large" condition, so this is technically also a
bug fix. :)

Here's the chain of callers, and resolution identifying each one as now
handling the correct return value:

kernfs_path_from_node_locked()
kernfs_path_from_node()
pr_cont_kernfs_path()
returns void
kernfs_path()
sysfs_warn_dup()
return value ignored
cgroup_path()
blkg_path()
bfq_bic_update_cgroup()
return value ignored
TRACE_IOCG_PATH()
return value ignored
TRACE_CGROUP_PATH()
return value ignored
perf_event_cgroup()
return value ignored
task_group_path()
return value ignored
damon_sysfs_memcg_path_eq()
return value ignored
get_mm_memcg_path()
return value ignored
lru_gen_seq_show()
return value ignored
cgroup_path_from_kernfs_id()
return value ignored
cgroup_show_path()
already converted "too large" error to negative value
cgroup_path_ns_locked()
cgroup_path_ns()
bpf_iter_cgroup_show_fdinfo()
return value ignored
cgroup1_release_agent()
wasn't checking "too large" error
proc_cgroup_show()
already converted "too large" to negative value

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Waiman Long <longman@redhat.com>
Cc: <cgroups@vger.kernel.org>
Co-developed-by: Azeem Shaikh <azeemshaikh38@gmail.com>
Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
Link: https://lore.kernel.org/r/20231116192127.1558276-3-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20231212211741.164376-3-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 1be59c97c83c ("cgroup/cpuset: Prevent UAF in proc_cpuset_show()")
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Merge tag 'v6.6.33' into dev-6.6

This is the 6.6.33 stable release

sched/fair: Allow disabling sched_balance_newidle with sched_relax_domain_level

[ Upstream commit a1fd0b9d751f840df23ef0e75b691fc00cfd4743 ]

Change relax_domain_level checks so that it would be pos

sched/fair: Allow disabling sched_balance_newidle with sched_relax_domain_level

[ Upstream commit a1fd0b9d751f840df23ef0e75b691fc00cfd4743 ]

Change relax_domain_level checks so that it would be possible
to include or exclude all domains from newidle balancing.

This matches the behavior described in the documentation:

-1 no request. use system default or follow request of others.
0 no search.
1 search siblings (hyperthreads in a core).

"2" enables levels 0 and 1, level_max excludes the last (level_max)
level, and level_max+1 includes all levels.

Fixes: 1d3504fcf560 ("sched, cpuset: customize sched domains, core")
Signed-off-by: Vitalii Bursov <vitaly@bursov.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Link: https://lore.kernel.org/r/bd6de28e80073c79466ec6401cdeae78f0d4423d.1714488502.git.vitaly@bursov.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Merge tag 'v6.6.24' into dev-6.6

This is the 6.6.24 stable release

cgroup/cpuset: Fix retval in update_cpumask()

commit 25125a4762835d62ba1e540c1351d447fc1f6c7c upstream.

The update_cpumask(), checks for newly requested cpumask by calling
validate_change(), which

cgroup/cpuset: Fix retval in update_cpumask()

commit 25125a4762835d62ba1e540c1351d447fc1f6c7c upstream.

The update_cpumask(), checks for newly requested cpumask by calling
validate_change(), which returns an error on passing an invalid set
of cpu(s). Independent of the error returned, update_cpumask() always
returns zero, suppressing the error and returning success to the user
on writing an invalid cpu range for a cpuset. Fix it by returning
retval instead, which is returned by validate_change().

Fixes: 99fe36ba6fc1 ("cgroup/cpuset: Improve temporary cpumasks handling")
Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Cc: stable@vger.kernel.org # v6.6+
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Merge tag 'v6.6.6' into dev-6.6

This is the 6.6.6 stable release

Signed-off-by: Joel Stanley <joel@jms.id.au>

cgroup/cpuset: Fix load balance state in update_partition_sd_lb()

[ Upstream commit 6fcdb0183bf024a70abccb0439321c25891c708d ]

Commit a86ce68078b2 ("cgroup/cpuset: Extract out CS_CPU_EXCLUSIVE
& CS

cgroup/cpuset: Fix load balance state in update_partition_sd_lb()

[ Upstream commit 6fcdb0183bf024a70abccb0439321c25891c708d ]

Commit a86ce68078b2 ("cgroup/cpuset: Extract out CS_CPU_EXCLUSIVE
& CS_SCHED_LOAD_BALANCE handling") adds a new helper function
update_partition_sd_lb() to update the load balance state of the
cpuset. However the new load balance is determined by just looking at
whether the cpuset is a valid isolated partition root or not. That is
not enough if the cpuset is not a valid partition root but its parent
is in the isolated state (load balance off). Update the function to
set the new state to be the same as its parent in this case like what
has been done in commit c8c926200c55 ("cgroup/cpuset: Inherit parent's
load balance state in v2").

Fixes: a86ce68078b2 ("cgroup/cpuset: Extract out CS_CPU_EXCLUSIVE & CS_SCHED_LOAD_BALANCE handling")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Merge drm/drm-fixes into drm-misc-fixes

Forwarding to v6.6-rc1.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Merge tag 'cgroup-for-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup updates from Tejun Heo:

- Per-cpu cpu usage stats are now tracked

This currently isn't printed

Merge tag 'cgroup-for-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup updates from Tejun Heo:

- Per-cpu cpu usage stats are now tracked

This currently isn't printed out in the cgroupfs interface and can
only be accessed through e.g. BPF. Should decide on a not-too-ugly
way to show per-cpu stats in cgroupfs

- cpuset received some cleanups and prepatory patches for the pending
cpus.exclusive patchset which will allow cpuset partitions to be
created below non-partition parents, which should ease the management
of partition cpusets

- A lot of code and documentation cleanup patches

- tools/testing/selftests/cgroup/test_cpuset.c added

* tag 'cgroup-for-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (32 commits)
cgroup: Avoid -Wstringop-overflow warnings
cgroup:namespace: Remove unused cgroup_namespaces_init()
cgroup/rstat: Record the cumulative per-cpu time of cgroup and its descendants
cgroup: clean up if condition in cgroup_pidlist_start()
cgroup: fix obsolete function name in cgroup_destroy_locked()
Documentation: cgroup-v2.rst: Correct number of stats entries
cgroup: fix obsolete function name above css_free_rwork_fn()
cgroup/cpuset: fix kernel-doc
cgroup: clean up printk()
cgroup: fix obsolete comment above cgroup_create()
docs: cgroup-v1: fix typo
docs: cgroup-v1: correct the term of Page Cache organization in inode
cgroup/misc: Store atomic64_t reads to u64
cgroup/misc: Change counters to be explicit 64bit types
cgroup/misc: update struct members descriptions
cgroup: remove cgrp->kn check in css_populate_dir()
cgroup: fix obsolete function name
cgroup: use cached local variable parent in for loop
cgroup: remove obsolete comment above struct cgroupstats
cgroup: put cgroup_tryget_css() inside CONFIG_CGROUP_SCHED
...

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Merge branch 'next' into for-linus

Prepare input updates for 6.6 merge window.

Merge drm/drm-next into drm-intel-next

Catching-up with drm-next and drm-intel-gt-next.
It will unblock a code refactor around the platform
definitions (names vs acronyms).

Signed-off-by: Rodrigo V

Merge drm/drm-next into drm-intel-next

Catching-up with drm-next and drm-intel-gt-next.
It will unblock a code refactor around the platform
definitions (names vs acronyms).

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

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Merge drm/drm-next into drm-intel-gt-next

Need to pull in b3e4aae612ec ("drm/i915/hdcp: Modify hdcp_gsc_message msg sending mechanism") as
a dependency for https://patchwork.freedesktop.org/series/1

Merge drm/drm-next into drm-intel-gt-next

Need to pull in b3e4aae612ec ("drm/i915/hdcp: Modify hdcp_gsc_message msg sending mechanism") as
a dependency for https://patchwork.freedesktop.org/series/121735/

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

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cgroup/cpuset: fix kernel-doc

Add kernel-doc of param @rotor to fix warnings:

kernel/cgroup/cpuset.c:4162: warning: Function parameter or member
'rotor' not described in 'cpuset_spread_node'
kernel

cgroup/cpuset: fix kernel-doc

Add kernel-doc of param @rotor to fix warnings:

kernel/cgroup/cpuset.c:4162: warning: Function parameter or member
'rotor' not described in 'cpuset_spread_node'
kernel/cgroup/cpuset.c:3771: warning: Function parameter or member
'work' not described in 'cpuset_hotplug_workfn'

Signed-off-by: Cai Xinchen <caixinchen1@huawei.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

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Merge drm/drm-next into drm-misc-next

Backmerging to get v6.5-rc2.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Merge tag 'v6.4' into next

Sync up with mainline to bring in updates to shared infrastructure.

ASoC: Merge v6.5-rc2

Get a similar baseline to my other branches, and fixes for people using
the branch.

Merge v6.5-rc1 into drm-misc-fixes

Boris needs 6.5-rc1 in drm-misc-fixes to prevent a conflict.

Signed-off-by: Maxime Ripard <mripard@kernel.org>

cgroup/cpuset: Allow suppression of sched domain rebuild in update_cpumasks_hier()

A single partition setup and tear-down operation can lead to
multiple rebuild_sched_domains_locked() calls which is

cgroup/cpuset: Allow suppression of sched domain rebuild in update_cpumasks_hier()

A single partition setup and tear-down operation can lead to
multiple rebuild_sched_domains_locked() calls which is a waste of
effort. This can partly be mitigated by adding a flag to suppress the
rebuild_sched_domains_locked() call in update_cpumasks_hier(). Since
a Boolean flag has already been passed as the 3rd argument to
update_cpumasks_hier(), we can extend that to a full flag word.

The sched domain rebuild suppression is now enabled in
update_sibling_cpumasks() as all it callers will do the sched domain
rebuild after its return later on anyway.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

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cgroup/cpuset: Improve temporary cpumasks handling

The limitation that update_parent_subparts_cpumask() can only use
addmask & delmask in the given tmp cpumasks is fragile and may lead to
unexpected

cgroup/cpuset: Improve temporary cpumasks handling

The limitation that update_parent_subparts_cpumask() can only use
addmask & delmask in the given tmp cpumasks is fragile and may lead to
unexpected error.

Fix this problem by allocating/freeing a struct tmpmasks in
update_cpumask() to avoid reusing the cpumasks in trial_cs.

With this change, we can move the update_tasks_cpumask() for the
parent and update_sibling_cpumasks() for the sibling to inside
update_parent_subparts_cpumask().

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

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cgroup/cpuset: Extract out CS_CPU_EXCLUSIVE & CS_SCHED_LOAD_BALANCE handling

Extract out the setting of CS_CPU_EXCLUSIVE and CS_SCHED_LOAD_BALANCE
flags as well as the rebuilding of scheduling domai

cgroup/cpuset: Extract out CS_CPU_EXCLUSIVE & CS_SCHED_LOAD_BALANCE handling

Extract out the setting of CS_CPU_EXCLUSIVE and CS_SCHED_LOAD_BALANCE
flags as well as the rebuilding of scheduling domains into the new
update_partition_exclusive() and update_partition_sd_lb() helper
functions to simplify the logic. The update_partition_exclusive()
helper is called mainly at the beginning of the caller, but it may be
called at the end too. The update_partition_sd_lb() helper is called
at the end of the caller.

This patch should reduce the chance that cpuset partition will end up
in an incorrect state.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

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cgroup/cpuset: Inherit parent's load balance state in v2

Since commit f28e22441f35 ("cgroup/cpuset: Add a new isolated
cpus.partition type"), the CS_SCHED_LOAD_BALANCE bit of a v2 cpuset
can be on o

cgroup/cpuset: Inherit parent's load balance state in v2

Since commit f28e22441f35 ("cgroup/cpuset: Add a new isolated
cpus.partition type"), the CS_SCHED_LOAD_BALANCE bit of a v2 cpuset
can be on or off. The child cpusets of a partition root must have the
same setting as its parent or it may screw up the rebuilding of sched
domains. Fix this problem by making sure the a child v2 cpuset will
follows its parent cpuset load balance state unless the child cpuset
is a new partition root itself.

Fixes: f28e22441f35 ("cgroup/cpuset: Add a new isolated cpus.partition type")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

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cpuset: Allow setscheduler regardless of manipulated task

When we migrate a task between two cgroups, one of the checks is a
verification whether we can modify task's scheduler settings
(cap_task_se

cpuset: Allow setscheduler regardless of manipulated task

When we migrate a task between two cgroups, one of the checks is a
verification whether we can modify task's scheduler settings
(cap_task_setscheduler()).

An implicit migration occurs also when enabling a controller on the
unified hierarchy (think of parent to child migration). The
aforementioned check may be problematic if the caller of the migration
(enabling a controller) has no permissions over migrated tasks.
For instance, a user's cgroup that ends up running a process of a
different user. Although cgroup permissions are configured favorably,
the enablement fails due to the foreign process [1].

Change the behavior by relaxing the permissions check on the unified
hierarchy when no effective change would happen.
This is in accordance with unified hierarchy attachment behavior when
permissions of the source to target cgroups are decisive whereas the
migrated task is opaque (as opposed to more restrictive check in
__cgroup1_procs_write()).

Notice that foreign task's affinity may still be modified if the user
can modify destination cgroup's cpuset attributes
(update_tasks_cpumask() does no permissions check). The permissions
check could thus be skipped on v2 even when affinity changes. Stay
conservative in this patch though.

[1] https://github.com/systemd/systemd/issues/18293#issuecomment-831205649

Signed-off-by: Michal Koutný <mkoutny@suse.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

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cgroup/cpuset: avoid unneeded cpuset_mutex re-lock

cpuset_mutex unlock and lock pair is only needed when transferring tasks
out of empty cpuset. Avoid unneeded cpuset_mutex re-lock when !is_empty
to

cgroup/cpuset: avoid unneeded cpuset_mutex re-lock

cpuset_mutex unlock and lock pair is only needed when transferring tasks
out of empty cpuset. Avoid unneeded cpuset_mutex re-lock when !is_empty
to save cpu cycles.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

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