linux/kernel/cgroup, branch v6.8

cgroup/cpuset: Fix retval in update_cpumask()

2024-02-29T20:30:35Z

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 Reviewed-by: Waiman Long Cc: stable@vger.kernel.org # v6.6+ Signed-off-by: Tejun Heo

cgroup/cpuset: Fix a memory leak in update_exclusive_cpumask()

2024-02-28T18:02:55Z

Fix a possible memory leak in update_exclusive_cpumask() by moving the alloc_cpumasks() down after the validate_change() check which can fail and still before the temporary cpumasks are needed. Fixes: e2ffe502ba45 ("cgroup/cpuset: Add cpuset.cpus.exclusive for v2") Reported-and-tested-by: Mirsad Todorovac Closes: https://lore.kernel.org/lkml/14915689-27a3-4cd8-80d2-9c30d0c768b6@alu.unizg.hr Signed-off-by: Waiman Long Signed-off-by: Tejun Heo Cc: stable@vger.kernel.org # v6.7+

Merge tag 'driver-core-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2024-01-18T17:48:40Z

Pull driver core updates from Greg KH: "Here are the set of driver core and kernfs changes for 6.8-rc1. Nothing major in here this release cycle, just lots of small cleanups and some tweaks on kernfs that in the very end, got reverted and will come back in a safer way next release cycle. Included in here are: - more driver core 'const' cleanups and fixes - fw_devlink=rpm is now the default behavior - kernfs tiny changes to remove some string functions - cpu handling in the driver core is updated to work better on many systems that add topologies and cpus after booting - other minor changes and cleanups All of the cpu handling patches have been acked by the respective maintainers and are coming in here in one series. Everything has been in linux-next for a while with no reported issues" * tag 'driver-core-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (51 commits) Revert "kernfs: convert kernfs_idr_lock to an irq safe raw spinlock" kernfs: convert kernfs_idr_lock to an irq safe raw spinlock class: fix use-after-free in class_register() PM: clk: make pm_clk_add_notifier() take a const pointer EDAC: constantify the struct bus_type usage kernfs: fix reference to renamed function driver core: device.h: fix Excess kernel-doc description warning driver core: class: fix Excess kernel-doc description warning driver core: mark remaining local bus_type variables as const driver core: container: make container_subsys const driver core: bus: constantify subsys_register() calls driver core: bus: make bus_sort_breadthfirst() take a const pointer kernfs: d_obtain_alias(NULL) will do the right thing... driver core: Better advertise dev_err_probe() kernfs: Convert kernfs_path_from_node_locked() from strlcpy() to strscpy() kernfs: Convert kernfs_name_locked() from strlcpy() to strscpy() kernfs: Convert kernfs_walk_ns() from strlcpy() to strscpy() initramfs: Expose retained initrd as sysfs file fs/kernfs/dir: obey S_ISGID kernel/cgroup: use kernfs_create_dir_ns() ...

Merge tag 'cgroup-for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

2024-01-09T04:04:02Z

Pull cgroup updates from Tejun Heo: - Yafang Shao added task_get_cgroup1() helper to enable a similar BPF helper so that BPF progs can be more useful on cgroup1 hierarchies. While cgroup1 is mostly in maintenance mode, this addition is very small while having an outsized usefulness for users who are still on cgroup1. Yafang also optimized root cgroup list access by making it RCU protected in the process. - Waiman Long optimized rstat operation leading to substantially lower and more consistent lock hold time while flushing the hierarchical statistics. As the lock can be acquired briefly in various hot paths, this reduction has cascading benefits. - Waiman also improved the quality of isolation for cpuset's isolated partitions. CPUs which are allocated to isolated partitions are now excluded from running unbound work items and cpu_is_isolated() test which is used by vmstat and memcg to reduce interference now includes cpuset isolated CPUs. While it isn't there yet, the hope is eventually reaching parity with the isolation level provided by the `isolcpus` boot param but in a dynamic manner. * tag 'cgroup-for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: Move rcu_head up near the top of cgroup_root cgroup/cpuset: Include isolated cpuset CPUs in cpu_is_isolated() check cgroup: Avoid false cacheline sharing of read mostly rstat_cpu cgroup/rstat: Optimize cgroup_rstat_updated_list() cgroup: Fix documentation for cpu.idle cgroup/cpuset: Expose cpuset.cpus.isolated workqueue: Move workqueue_set_unbound_cpumask() and its helpers inside CONFIG_SYSFS cgroup/rstat: Reduce cpu_lock hold time in cgroup_rstat_flush_locked() cgroup/cpuset: Take isolated CPUs out of workqueue unbound cpumask cgroup/cpuset: Keep track of CPUs in isolated partitions selftests/cgroup: Minor code cleanup and reorganization of test_cpuset_prs.sh workqueue: Add workqueue_unbound_exclude_cpumask() to exclude CPUs from wq_unbound_cpumask selftests: cgroup: Fixes a typo in a comment cgroup: Add a new helper for cgroup1 hierarchy cgroup: Add annotation for holding namespace_sem in current_cgns_cgroup_from_root() cgroup: Eliminate the need for cgroup_mutex in proc_cgroup_show() cgroup: Make operations on the cgroup root_list RCU safe cgroup: Remove unnecessary list_empty()

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

2023-12-15T16:25:10Z

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 Cc: Tejun Heo Cc: Zefan Li Cc: Johannes Weiner Cc: Waiman Long Cc: Co-developed-by: Azeem Shaikh Signed-off-by: Azeem Shaikh Link: https://lore.kernel.org/r/20231116192127.1558276-3-keescook@chromium.org Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20231212211741.164376-3-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman

kernel/cgroup: use kernfs_create_dir_ns()

2023-12-15T16:22:40Z

By passing the fsugid to kernfs_create_dir_ns(), we don't need cgroup_kn_set_ugid() any longer. That function was added for exactly this purpose by commit 49957f8e2a43 ("cgroup: newly created dirs and files should be owned by the creator"). Eliminating this piece of duplicate code means we benefit from future improvements to kernfs_create_dir_ns(); for example, both are lacking S_ISGID support currently, which my next patch will add to kernfs_create_dir_ns(). It cannot (easily) be added to cgroup_kn_set_ugid() because we can't dereference struct kernfs_iattrs from there. -- v1 -> v2: 12-digit commit id Signed-off-by: Max Kellermann Acked-by: Tejun Heo Link: https://lore.kernel.org/r/20231208093310.297233-1-max.kellermann@ionos.com Signed-off-by: Greg Kroah-Hartman

Merge tag 'cgroup-for-6.7-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

2023-12-07T20:42:40Z

Pull cgroup fix from Tejun Heo: "Just one fix. Commit f5d39b020809 ("freezer,sched: Rewrite core freezer logic") changed how freezing state is recorded which made cgroup_freezing() disagree with the actual state of the task while thawing triggering a warning. Fix it by updating cgroup_freezing()" * tag 'cgroup-for-6.7-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup_freezer: cgroup_freezing: Check if not frozen

cgroup/cpuset: Include isolated cpuset CPUs in cpu_is_isolated() check

2023-12-06T19:37:28Z

Currently, the cpu_is_isolated() function checks only the statically isolated CPUs specified via the "isolcpus" and "nohz_full" kernel command line options. This function is used by vmstat and memcg to reduce interference with isolated CPUs by not doing stat flushing or scheduling works on those CPUs. Workloads running on isolated CPUs within isolated cpuset partitions should receive the same treatment to reduce unnecessary interference. This patch introduces a new cpuset_cpu_is_isolated() function to be called by cpu_is_isolated() so that the set of dynamically created cpuset isolated CPUs will be included in the check. Assuming that testing a bit in a cpumask is atomic, no synchronization primitive is currently used to synchronize access to the cpuset's isolated_cpus mask. Signed-off-by: Waiman Long Signed-off-by: Tejun Heo

cgroup/rstat: Optimize cgroup_rstat_updated_list()

2023-12-01T17:40:04Z

The current design of cgroup_rstat_cpu_pop_updated() is to traverse the updated tree in a way to pop out the leaf nodes first before their parents. This can cause traversal of multiple nodes before a leaf node can be found and popped out. IOW, a given node in the tree can be visited multiple times before the whole operation is done. So it is not very efficient and the code can be hard to read. With the introduction of cgroup_rstat_updated_list() to build a list of cgroups to be flushed first before any flushing operation is being done, we can optimize the way the updated tree nodes are being popped by pushing the parents first to the tail end of the list before their children. In this way, most updated tree nodes will be visited only once with the exception of the subtree root as we still need to go back to its parent and popped it out of its updated_children list. This also makes the code easier to read. Signed-off-by: Waiman Long Signed-off-by: Tejun Heo

cgroup_freezer: cgroup_freezing: Check if not frozen

2023-11-28T18:04:03Z

__thaw_task() was recently updated to warn if the task being thawed was part of a freezer cgroup that is still currently freezing: void __thaw_task(struct task_struct *p) { ... if (WARN_ON_ONCE(freezing(p))) goto unlock; This has exposed a bug in cgroup1 freezing where when CGROUP_FROZEN is asserted, the CGROUP_FREEZING bits are not also cleared at the same time. Meaning, when a cgroup is marked FROZEN it continues to be marked FREEZING as well. This causes the WARNING to trigger, because cgroup_freezing() thinks the cgroup is still freezing. There are two ways to fix this: 1. Whenever FROZEN is set, clear FREEZING for the cgroup and all children cgroups. 2. Update cgroup_freezing() to also verify that FROZEN is not set. This patch implements option (2), since it's smaller and more straightforward. Signed-off-by: Tim Van Patten Tested-by: Mark Hasemeyer Fixes: f5d39b020809 ("freezer,sched: Rewrite core freezer logic") Cc: stable@vger.kernel.org # v6.1+ Signed-off-by: Tejun Heo