[ Upstream commit a22b3d54de94f82ca057cc2ebf9496fa91ebf698 ]

There is a possible race between removing a cgroup diectory that is
a partition root and the creation of a new partition.  The partition
to be removed can be dying but still online, it doesn't not currently
participate in checking for exclusive CPUs conflict, but the exclusive
CPUs are still there in subpartitions_cpus and isolated_cpus. These
two cpumasks are global states that affect the operation of cpuset
partitions. The exclusive CPUs in dying cpusets will only be removed
when cpuset_css_offline() function is called after an RCU delay.

As a result, it is possible that a new partition can be created with
exclusive CPUs that overlap with those of a dying one. When that dying
partition is finally offlined, it removes those overlapping exclusive
CPUs from subpartitions_cpus and maybe isolated_cpus resulting in an
incorrect CPU configuration.

This bug was found when a warning was triggered in
remote_partition_disable() during testing because the subpartitions_cpus
mask was empty.

One possible way to fix this is to iterate the dying cpusets as well and
avoid using the exclusive CPUs in those dying cpusets. However, this
can still cause random partition creation failures or other anomalies
due to racing. A better way to fix this race is to reset the partition
state at the moment when a cpuset is being killed.

Introduce a new css_killed() CSS function pointer and call it, if
defined, before setting CSS_DYING flag in kill_css(). Also update the
css_is_dying() helper to use the CSS_DYING flag introduced by commit
33c35aa48178 ("cgroup: Prevent kill_css() from being called more than
once") for proper synchronization.

Add a new cpuset_css_killed() function to reset the partition state of
a valid partition root if it is being killed.

Fixes: ee8dde0cd2ce ("cpuset: Add new v2 cpuset.sched.partition flag")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 8bf450f3aec3d1bbd725d179502c64b8992588e4 ]

When remote_partition_disable() is called to disable a remote partition,
it always sets the partition to an invalid partition state. It should
only do so if an error code (prs_err) has been set. Correct that and
add proper error code in places where remote_partition_disable() is
called due to error.

Fixes: 181c8e091aae ("cgroup/cpuset: Introduce remote partition")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 668e041662e92ab3ebcb9eb606d3ec01884546ab ]

Before commit f0af1bfc27b5 ("cgroup/cpuset: Relax constraints to
partition & cpus changes"), a cpuset partition cannot be enabled if not
all the requested CPUs can be granted from the parent cpuset. After
that commit, a cpuset partition can be created even if the requested
exclusive CPUs contain CPUs not allowed its parent.  The delmask
containing exclusive CPUs to be removed from its parent wasn't
adjusted accordingly.

That is not a problem until the introduction of a new isolated_cpus
mask in commit 11e5f407b64a ("cgroup/cpuset: Keep track of CPUs in
isolated partitions") as the CPUs in the delmask may be added directly
into isolated_cpus.

As a result, isolated_cpus may incorrectly contain CPUs that are not
isolated leading to incorrect data reporting. Fix this by adjusting
the delmask to reflect the actual exclusive CPUs for the creation of
the partition.

Fixes: 11e5f407b64a ("cgroup/cpuset: Keep track of CPUs in isolated partitions")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 2ff899e3516437354204423ef0a94994717b8e6a ]

Rebuilding of root domains accounting information (total_bw) is
currently broken on some cases, e.g. suspend/resume on aarch64. Problem
is that the way we keep track of domain changes and try to add bandwidth
back is convoluted and fragile.

Fix it by simplify things by making sure bandwidth accounting is cleared
and completely restored after root domains changes (after root domains
are again stable).

To be sure we always call dl_rebuild_rd_accounting while holding
cpuset_mutex we also add cpuset_reset_sched_domains() wrapper.

Fixes: 53916d5fd3c0 ("sched/deadline: Check bandwidth overflow earlier for hotplug")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Co-developed-by: Waiman Long <llong@redhat.com>
Signed-off-by: Waiman Long <llong@redhat.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/Z9MRfeJKJUOyUSto@jlelli-thinkpadt14gen4.remote.csb
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 56209334dda1832c0a919e1d74768c6d0f3b2ca9 ]

Create wrappers for sched_domains_mutex so that it can transparently be
used on both CONFIG_SMP and !CONFIG_SMP, as some function will need to
do.

Fixes: 53916d5fd3c0 ("sched/deadline: Check bandwidth overflow earlier for hotplug")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Waiman Long <longman@redhat.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/Z9MP5Oq9RB8jBs3y@jlelli-thinkpadt14gen4.remote.csb
Signed-off-by: Sasha Levin <sashal@kernel.org>

commit c4af66a95aa3bc1d4f607ebd4eea524fb58946e3 upstream.

The commit b824766504e4 ("cgroup/rstat: add force idle show helper")
retrieves forceidle_time outside cgroup_rstat_lock for non-root cgroups
which can be potentially inconsistent with other stats.

Rather than reverting that commit, fix it in a way that retains the
effort of cleaning up the ifdef-messes.

Fixes: b824766504e4 ("cgroup/rstat: add force idle show helper")
Signed-off-by: Abel Wu <wuyun.abel@bytedance.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

An reset signal polarity fix for the jd9365da-h3 panel, a folio handling
fix and config fix in nouveau, a dmem cgroup descendant pool handling
fix, and a missing header for amdxdna.

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Maxime Ripard <mripard@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250220-glorious-cockle-of-might-5b35f7@houat

The current implementation has a bug: If the current css doesn't
contain any pool that is a descendant of the "pool" (i.e. when
found_descendant == false), then "pool" will point to some unrelated
pool. If the current css has a child, we'll overwrite parent_pool with
this unrelated pool on the next iteration.

Since we can just check whether a pool refers to the same region to
determine whether or not it's related, all the additional pool tracking
is unnecessary, so just switch to using css_for_each_descendant_pre for
traversal.

Fixes: b168ed458dde ("kernel/cgroup: Add "dmem" memory accounting cgroup")
Signed-off-by: Friedrich Vock <friedrich.vock@gmx.de>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250127152754.21325-1-friedrich.vock@gmx.de
Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>

The CPU usage time is the time when user, system or both are using the CPU.
Steal time is the time when CPU is waiting to be run by the Hypervisor. It
should not be added to the CPU usage time, hence removing it from the
usage_usec entry.

Fixes: 936f2a70f2077 ("cgroup: add cpu.stat file to root cgroup")
Acked-by: Axel Busch <axel.busch@ibm.com>
Acked-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Muhammad Adeel <muhammad.adeel@ibm.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Tejun reported the following race between fork() and cgroup.kill at [1].

Tejun:
  I was looking at cgroup.kill implementation and wondering whether there
  could be a race window. So, __cgroup_kill() does the following:

   k1. Set CGRP_KILL.
   k2. Iterate tasks and deliver SIGKILL.
   k3. Clear CGRP_KILL.

  The copy_process() does the following:

   c1. Copy a bunch of stuff.
   c2. Grab siglock.
   c3. Check fatal_signal_pending().
   c4. Commit to forking.
   c5. Release siglock.
   c6. Call cgroup_post_fork() which puts the task on the css_set and tests
       CGRP_KILL.

  The intention seems to be that either a forking task gets SIGKILL and
  terminates on c3 or it sees CGRP_KILL on c6 and kills the child. However, I
  don't see what guarantees that k3 can't happen before c6. ie. After a
  forking task passes c5, k2 can take place and then before the forking task
  reaches c6, k3 can happen. Then, nobody would send SIGKILL to the child.
  What am I missing?

This is indeed a race. One way to fix this race is by taking
cgroup_threadgroup_rwsem in write mode in __cgroup_kill() as the fork()
side takes cgroup_threadgroup_rwsem in read mode from cgroup_can_fork()
to cgroup_post_fork(). However that would be heavy handed as this adds
one more potential stall scenario for cgroup.kill which is usually
called under extreme situation like memory pressure.

To fix this race, let's maintain a sequence number per cgroup which gets
incremented on __cgroup_kill() call. On the fork() side, the
cgroup_can_fork() will cache the sequence number locally and recheck it
against the cgroup's sequence number at cgroup_post_fork() site. If the
sequence numbers mismatch, it means __cgroup_kill() can been called and
we should send SIGKILL to the newly created task.

Reported-by: Tejun Heo <tj@kernel.org>
Closes: https://lore.kernel.org/all/Z5QHE2Qn-QZ6M-KW@slm.duckdns.org/ [1]
Fixes: 661ee6280931 ("cgroup: introduce cgroup.kill")
Cc: stable@vger.kernel.org # v5.14+
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>