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2022-09-06cgroup: Remove CFTYPE_PRESSURETejun Heo
CFTYPE_PRESSURE is used to flag PSI related files so that they are not created if PSI is disabled during boot. It's a bit weird to use a generic flag to mark a specific file type. Let's instead move the PSI files into its own cftypes array and add/rm them conditionally. This is a bit more code but cleaner. No userland visible changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org>
2022-09-06cgroup: Improve cftype add/rm error handlingTejun Heo
Let's track whether a cftype is currently added or not using a new flag __CFTYPE_ADDED so that duplicate operations can be failed safely and consistently allow using empty cftypes. Signed-off-by: Tejun Heo <tj@kernel.org>
2022-09-04cgroup: Remove data-race around cgrp_dfl_visibleTejun Heo
There's a seemingly harmless data-race around cgrp_dfl_visible detected by kernel concurrency sanitizer. Let's remove it by throwing WRITE/READ_ONCE at it. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Abhishek Shah <abhishek.shah@columbia.edu> Cc: Gabriel Ryan <gabe@cs.columbia.edu> Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Link: https://lore.kernel.org/netdev/20220819072256.fn7ctciefy4fc4cu@wittgenstein/
2022-09-01cgroup: Implement cgroup_file_show()Tejun Heo
Add cgroup_file_show() which allows toggling visibility of a cgroup file using the new kernfs_show(). This will be used to hide psi interface files on cgroups where it's disabled. Cc: Chengming Zhou <zhouchengming@bytedance.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Chengming Zhou <zhouchengming@bytedance.com> Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com> Signed-off-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20220828050440.734579-10-tj@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-26cgroup: Use cgroup_attach_{lock,unlock}() from cgroup_attach_task_all()Tetsuo Handa
No behavior changes; preparing for potential locking changes in future. Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by:Mukesh Ojha <quic_mojha@quicinc.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2022-08-26Merge branch 'for-6.0-fixes' into for-6.1Tejun Heo
Pulling to receive 43626dade36f ("group: Add missing cpus_read_lock() to cgroup_attach_task_all()") for a follow-up patch.
2022-08-26cgroup: Homogenize cgroup_get_from_id() return valueMichal Koutný
Cgroup id is user provided datum hence extend its return domain to include possible error reason (similar to cgroup_get_from_fd()). This change also fixes commit d4ccaf58a847 ("bpf: Introduce cgroup iter") that would use NULL instead of proper error handling in d4ccaf58a847 ("bpf: Introduce cgroup iter"). Additionally, neither of: fc_appid_store, bpf_iter_attach_cgroup, mem_cgroup_get_from_ino (callers of cgroup_get_from_fd) is built without CONFIG_CGROUPS (depends via CONFIG_BLK_CGROUP, direct, transitive CONFIG_MEMCG respectively) transitive, so drop the singular definition not needed with !CONFIG_CGROUPS. Fixes: d4ccaf58a847 ("bpf: Introduce cgroup iter") Signed-off-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2022-08-26cgroup: cgroup: Honor caller's cgroup NS when resolving cgroup idMichal Koutný
Cgroup ids are resolved in the global scope. That may be needed sometime (in future) but currently it violates virtual view provided through cgroup namespaces. There are currently following users of the resolution: - fc_appid_store - bpf_iter_attach_cgroup - mem_cgroup_get_from_ino None of the is a called on behalf of kernel but the resolution is made with proper userspace context, hence the default to current->nsproxy makes sens. (This doesn't rule out cgroup_get_from_id with cgroup NS parameter in the future.) Since cgroup ids are defined on v2 hierarchy only, we simply check existence in the cgroup namespace by looking at ancestry on the default hierarchy. Fixes: 6b658c4863c1 ("scsi: cgroup: Add cgroup_get_from_id()") Signed-off-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2022-08-26cgroup: Honor caller's cgroup NS when resolving pathMichal Koutný
cgroup_get_from_path() is not widely used function. Its callers presume the path is resolved under cgroup namespace. (There is one caller currently and resolving in init NS won't make harm (netfilter). However, future users may be subject to different effects when resolving globally.) Since, there's currently no use for the global resolution, modify the existing function to take cgroup NS into account. Fixes: a79a908fd2b0 ("cgroup: introduce cgroup namespaces") Signed-off-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2022-08-25Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
drivers/net/ethernet/mellanox/mlx5/core/en_fs.c 21234e3a84c7 ("net/mlx5e: Fix use after free in mlx5e_fs_init()") c7eafc5ed068 ("net/mlx5e: Convert ethtool_steering member of flow_steering struct to pointer") https://lore.kernel.org/all/20220825104410.67d4709c@canb.auug.org.au/ https://lore.kernel.org/all/20220823055533.334471-1-saeed@kernel.org/ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-08-23cgroup: Fix race condition at rebind_subsystems()Jing-Ting Wu
Root cause: The rebind_subsystems() is no lock held when move css object from A list to B list,then let B's head be treated as css node at list_for_each_entry_rcu(). Solution: Add grace period before invalidating the removed rstat_css_node. Reported-by: Jing-Ting Wu <jing-ting.wu@mediatek.com> Suggested-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Jing-Ting Wu <jing-ting.wu@mediatek.com> Tested-by: Jing-Ting Wu <jing-ting.wu@mediatek.com> Link: https://lore.kernel.org/linux-arm-kernel/d8f0bc5e2fb6ed259f9334c83279b4c011283c41.camel@mediatek.com/T/ Acked-by: Mukesh Ojha <quic_mojha@quicinc.com> Fixes: a7df69b81aac ("cgroup: rstat: support cgroup1") Cc: stable@vger.kernel.org # v5.13+ Signed-off-by: Tejun Heo <tj@kernel.org>
2022-08-17cgroup: Fix threadgroup_rwsem <-> cpus_read_lock() deadlockTejun Heo
Bringing up a CPU may involve creating and destroying tasks which requires read-locking threadgroup_rwsem, so threadgroup_rwsem nests inside cpus_read_lock(). However, cpuset's ->attach(), which may be called with thredagroup_rwsem write-locked, also wants to disable CPU hotplug and acquires cpus_read_lock(), leading to a deadlock. Fix it by guaranteeing that ->attach() is always called with CPU hotplug disabled and removing cpus_read_lock() call from cpuset_attach(). Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-and-tested-by: Imran Khan <imran.f.khan@oracle.com> Reported-and-tested-by: Xuewen Yan <xuewen.yan@unisoc.com> Fixes: 05c7b7a92cc8 ("cgroup/cpuset: Fix a race between cpuset_attach() and cpu hotplug") Cc: stable@vger.kernel.org # v5.17+
2022-08-15sched/psi: Remove unused parameter nbytes of psi_trigger_create()Hao Jia
psi_trigger_create()'s 'nbytes' parameter is not used, so we can remove it. Signed-off-by: Hao Jia <jiahao.os@bytedance.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2022-08-15cgroup: Replace cgroup->ancestor_ids[] with ->ancestors[]Tejun Heo
Every cgroup knows all its ancestors through its ->ancestor_ids[]. There's no advantage to remembering the IDs instead of the pointers directly and this makes the array useless for finding an actual ancestor cgroup forcing cgroup_ancestor() to iteratively walk up the hierarchy instead. Let's replace cgroup->ancestor_ids[] with ->ancestors[] and remove the walking-up from cgroup_ancestor(). While at it, improve comments around cgroup_root->cgrp_ancestor_storage. This patch shouldn't cause user-visible behavior differences. v2: Update cgroup_ancestor() to use ->ancestors[]. v3: cgroup_root->cgrp_ancestor_storage's type is updated to match cgroup->ancestors[]. Better comments. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Namhyung Kim <namhyung@kernel.org>
2022-08-09cgroup: enable cgroup_get_from_file() on cgroup1Yosry Ahmed
cgroup_get_from_file() currently fails with -EBADF if called on cgroup v1. However, the current implementation works on cgroup v1 as well, so the restriction is unnecessary. This enabled cgroup_get_from_fd() to work on cgroup v1, which would be the only thing stopping bpf cgroup_iter from supporting cgroup v1. Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Hao Luo <haoluo@google.com> Link: https://lore.kernel.org/r/20220805214821.1058337-3-haoluo@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-08-03Merge tag 'cgroup-for-5.20' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: "Several core optimizations: - threadgroup_rwsem write locking is skipped when configuring controllers in empty subtrees. Combined with CLONE_INTO_CGROUP, this allows the common static usage pattern to not grab threadgroup_rwsem at all (glibc still doesn't seem ready for CLONE_INTO_CGROUP unfortunately). - threadgroup_rwsem used to be put into non-percpu mode by default due to latency concerns in specific use cases. There's no reason for everyone else to pay for it. Make the behavior optional. - psi no longer allocates memory when disabled. ... along with some code cleanups" * tag 'cgroup-for-5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: Skip subtree root in cgroup_update_dfl_csses() cgroup: remove "no" prefixed mount options cgroup: Make !percpu threadgroup_rwsem operations optional cgroup: Add "no" prefixed mount options cgroup: Elide write-locking threadgroup_rwsem when updating csses on an empty subtree cgroup.c: remove redundant check for mixable cgroup in cgroup_migrate_vet_dst cgroup.c: add helper __cset_cgroup_from_root to cleanup duplicated codes psi: dont alloc memory for psi by default
2022-07-28cgroup: Skip subtree root in cgroup_update_dfl_csses()Waiman Long
The cgroup_update_dfl_csses() function updates css associations when a cgroup's subtree_control file is modified. Any changes made to a cgroup's subtree_control file, however, will only affect its descendants but not the cgroup itself. So there is no point in migrating csses associated with that cgroup. We can skip them instead. Signed-off-by: Waiman Long <longman@redhat.com> Reviewed-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2022-07-27cgroup: remove "no" prefixed mount optionsTejun Heo
30312730bd02 ("cgroup: Add "no" prefixed mount options") added "no" prefixed mount options to allow turning them off and 6a010a49b63a ("cgroup: Make !percpu threadgroup_rwsem operations optional") added one more "no" prefixed mount option. However, Michal pointed out that the "no" prefixed options aren't necessary in allowing mount options to be turned off: # grep group /proc/mounts cgroup2 /sys/fs/cgroup cgroup2 rw,nosuid,nodev,relatime,nsdelegate,memory_recursiveprot 0 0 # mount -o remount,nsdelegate,memory_recursiveprot none /sys/fs/cgroup # grep cgroup /proc/mounts cgroup2 /sys/fs/cgroup cgroup2 rw,relatime,nsdelegate,memory_recursiveprot 0 0 Note that this is different from the remount behavior when the mount(1) is invoked without the device argument - "none": # grep cgroup /proc/mounts cgroup2 /sys/fs/cgroup cgroup2 rw,nosuid,nodev,noexec,relatime,nsdelegate,memory_recursiveprot 0 0 # mount -o remount,nsdelegate,memory_recursiveprot /sys/fs/cgroup # grep cgroup /proc/mounts cgroup2 /sys/fs/cgroup cgroup2 rw,nosuid,nodev,noexec,relatime,nsdelegate,memory_recursiveprot 0 0 While a bit confusing, given that there is a way to turn off the options, there's no reason to have the explicit "no" prefixed options. Let's remove them. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2022-07-23cgroup: Make !percpu threadgroup_rwsem operations optionalTejun Heo
3942a9bd7b58 ("locking, rcu, cgroup: Avoid synchronize_sched() in __cgroup_procs_write()") disabled percpu operations on threadgroup_rwsem because the impiled synchronize_rcu() on write locking was pushing up the latencies too much for android which constantly moves processes between cgroups. This makes the hotter paths - fork and exit - slower as they're always forced into the slow path. There is no reason to force this on everyone especially given that more common static usage pattern can now completely avoid write-locking the rwsem. Write-locking is elided when turning on and off controllers on empty sub-trees and CLONE_INTO_CGROUP enables seeding a cgroup without grabbing the rwsem. Restore the default percpu operations and introduce the mount option "favordynmods" and config option CGROUP_FAVOR_DYNMODS for users who need lower latencies for the dynamic operations. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Michal Koutn� <mkoutny@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Dmitry Shmidt <dimitrysh@google.com> Cc: Oleg Nesterov <oleg@redhat.com>
2022-07-22cgroup: Add "no" prefixed mount optionsTejun Heo
We allow modifying these mount options via remount. Let's add "no" prefixed variants so that they can be turned off too. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Michal Koutný <mkoutny@suse.com>
2022-07-22cgroup: Elide write-locking threadgroup_rwsem when updating csses on an ↵Tejun Heo
empty subtree cgroup_update_dfl_csses() write-lock the threadgroup_rwsem as updating the csses can trigger process migrations. However, if the subtree doesn't contain any tasks, there aren't gonna be any cgroup migrations. This condition can be trivially detected by testing whether mgctx.preloaded_src_csets is empty. Elide write-locking threadgroup_rwsem if the subtree is empty. After this optimization, the usage pattern of creating a cgroup, enabling the necessary controllers, and then seeding it with CLONE_INTO_CGROUP and then removing the cgroup after it becomes empty doesn't need to write-lock threadgroup_rwsem at all. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Michal Koutný <mkoutny@suse.com>
2022-06-27cgroup.c: remove redundant check for mixable cgroup in cgroup_migrate_vet_dstLin Feng
We have: int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp) { ... /* mixables don't care */ if (cgroup_is_mixable(dst_cgrp)) return 0; /* * If @dst_cgrp is already or can become a thread root or is * threaded, it doesn't matter. */ if (cgroup_can_be_thread_root(dst_cgrp) || cgroup_is_threaded(dst_cgrp)) return 0; ... } but in fact the entry of cgroup_can_be_thread_root() covers case that checking cgroup_is_mixable() as following: static bool cgroup_can_be_thread_root(struct cgroup *cgrp) { /* mixables don't care */ if (cgroup_is_mixable(cgrp)) return true; ... } so explicitly checking in cgroup_migrate_vet_dst is unnecessary. Signed-off-by: Lin Feng <linf@wangsu.com> Reviewed-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2022-06-16cgroup: Use separate src/dst nodes when preloading css_sets for migrationTejun Heo
Each cset (css_set) is pinned by its tasks. When we're moving tasks around across csets for a migration, we need to hold the source and destination csets to ensure that they don't go away while we're moving tasks about. This is done by linking cset->mg_preload_node on either the mgctx->preloaded_src_csets or mgctx->preloaded_dst_csets list. Using the same cset->mg_preload_node for both the src and dst lists was deemed okay as a cset can't be both the source and destination at the same time. Unfortunately, this overloading becomes problematic when multiple tasks are involved in a migration and some of them are identity noop migrations while others are actually moving across cgroups. For example, this can happen with the following sequence on cgroup1: #1> mkdir -p /sys/fs/cgroup/misc/a/b #2> echo $$ > /sys/fs/cgroup/misc/a/cgroup.procs #3> RUN_A_COMMAND_WHICH_CREATES_MULTIPLE_THREADS & #4> PID=$! #5> echo $PID > /sys/fs/cgroup/misc/a/b/tasks #6> echo $PID > /sys/fs/cgroup/misc/a/cgroup.procs the process including the group leader back into a. In this final migration, non-leader threads would be doing identity migration while the group leader is doing an actual one. After #3, let's say the whole process was in cset A, and that after #4, the leader moves to cset B. Then, during #6, the following happens: 1. cgroup_migrate_add_src() is called on B for the leader. 2. cgroup_migrate_add_src() is called on A for the other threads. 3. cgroup_migrate_prepare_dst() is called. It scans the src list. 4. It notices that B wants to migrate to A, so it tries to A to the dst list but realizes that its ->mg_preload_node is already busy. 5. and then it notices A wants to migrate to A as it's an identity migration, it culls it by list_del_init()'ing its ->mg_preload_node and putting references accordingly. 6. The rest of migration takes place with B on the src list but nothing on the dst list. This means that A isn't held while migration is in progress. If all tasks leave A before the migration finishes and the incoming task pins it, the cset will be destroyed leading to use-after-free. This is caused by overloading cset->mg_preload_node for both src and dst preload lists. We wanted to exclude the cset from the src list but ended up inadvertently excluding it from the dst list too. This patch fixes the issue by separating out cset->mg_preload_node into ->mg_src_preload_node and ->mg_dst_preload_node, so that the src and dst preloadings don't interfere with each other. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Mukesh Ojha <quic_mojha@quicinc.com> Reported-by: shisiyuan <shisiyuan19870131@gmail.com> Link: http://lkml.kernel.org/r/1654187688-27411-1-git-send-email-shisiyuan@xiaomi.com Link: https://www.spinics.net/lists/cgroups/msg33313.html Fixes: f817de98513d ("cgroup: prepare migration path for unified hierarchy") Cc: stable@vger.kernel.org # v3.16+
2022-06-16cgroup.c: add helper __cset_cgroup_from_root to cleanup duplicated codesLin Feng
No funtionality change, but save us some lines. Signed-off-by: Lin Feng <linf@wangsu.com> Acked-by: Mukesh Ojha <quic_mojha@quicinc.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2022-06-07psi: dont alloc memory for psi by defaultChen Wandun
Memory about struct psi_group is allocated by default for each cgroup even if psi_disabled is true, in this case, these allocated memory is waste, so alloc memory for struct psi_group only when psi_disabled is false. Signed-off-by: Chen Wandun <chenwandun@huawei.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2022-05-19cgroup: remove the superfluous judgmentShida Zhang
Remove the superfluous judgment since the function is never called for a root cgroup, as suggested by Tejun. Suggested-by: Tejun Heo <tj@kernel.org> Signed-off-by: Shida Zhang <zhangshida@kylinos.cn> Reviewed-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2022-05-18cgroup: Make cgroup_debug staticXiu Jianfeng
Make cgroup_debug static since it's only used in cgroup.c Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2022-03-28Merge tag 'driver-core-5.18-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core updates from Greg KH: "Here is the set of driver core changes for 5.18-rc1. Not much here, primarily it was a bunch of cleanups and small updates: - kobj_type cleanups for default_groups - documentation updates - firmware loader minor changes - component common helper added and take advantage of it in many drivers (the largest part of this pull request). All of these have been in linux-next for a while with no reported problems" * tag 'driver-core-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (54 commits) Documentation: update stable review cycle documentation drivers/base/dd.c : Remove the initial value of the global variable Documentation: update stable tree link Documentation: add link to stable release candidate tree devres: fix typos in comments Documentation: add note block surrounding security patch note samples/kobject: Use sysfs_emit instead of sprintf base: soc: Make soc_device_match() simpler and easier to read driver core: dd: fix return value of __setup handler driver core: Refactor sysfs and drv/bus remove hooks driver core: Refactor multiple copies of device cleanup scripts: get_abi.pl: Fix typo in help message kernfs: fix typos in comments kernfs: remove unneeded #if 0 guard ALSA: hda/realtek: Make use of the helper component_compare_dev_name video: omapfb: dss: Make use of the helper component_compare_dev power: supply: ab8500: Make use of the helper component_compare_dev ASoC: codecs: wcd938x: Make use of the helper component_compare/release_of iommu/mediatek: Make use of the helper component_compare/release_of drm: of: Make use of the helper component_release_of ...
2022-03-23Merge branch 'for-5.18' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: "All trivial cleanups without meaningful behavior changes" * 'for-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: cleanup comments cgroup: Fix cgroup_can_fork() and cgroup_post_fork() kernel-doc comment cgroup: rstat: retrieve current bstat to delta directly cgroup: rstat: use same convention to assign cgroup_base_stat
2022-02-28Merge 5.17-rc6 into driver-core-nextGreg Kroah-Hartman
We need the driver core fix in here as well for future changes. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-23kernfs: move struct kernfs_root out of the public view.Greg Kroah-Hartman
There is no need to have struct kernfs_root be part of kernfs.h for the whole kernel to see and poke around it. Move it internal to kernfs code and provide a helper function, kernfs_root_to_node(), to handle the one field that kernfs users were directly accessing from the structure. Cc: Imran Khan <imran.f.khan@oracle.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20220222070713.3517679-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-22Merge branch 'for-5.17-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup fixes from Tejun Heo: - Fix for a subtle bug in the recent release_agent permission check update - Fix for a long-standing race condition between cpuset and cpu hotplug - Comment updates * 'for-5.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cpuset: Fix kernel-doc cgroup-v1: Correct privileges check in release_agent writes cgroup: clarify cgroup_css_set_fork() cgroup/cpuset: Fix a race between cpuset_attach() and cpu hotplug
2022-02-22cgroup: clarify cgroup_css_set_fork()Christian Brauner
With recent fixes for the permission checking when moving a task into a cgroup using a file descriptor to a cgroup's cgroup.procs file and calling write() it seems a good idea to clarify CLONE_INTO_CGROUP permission checking with a comment. Cc: Tejun Heo <tj@kernel.org> Cc: <cgroups@vger.kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2022-01-18psi: Fix uaf issue when psi trigger is destroyed while being polledSuren Baghdasaryan
With write operation on psi files replacing old trigger with a new one, the lifetime of its waitqueue is totally arbitrary. Overwriting an existing trigger causes its waitqueue to be freed and pending poll() will stumble on trigger->event_wait which was destroyed. Fix this by disallowing to redefine an existing psi trigger. If a write operation is used on a file descriptor with an already existing psi trigger, the operation will fail with EBUSY error. Also bypass a check for psi_disabled in the psi_trigger_destroy as the flag can be flipped after the trigger is created, leading to a memory leak. Fixes: 0e94682b73bf ("psi: introduce psi monitor") Reported-by: syzbot+cdb5dd11c97cc532efad@syzkaller.appspotmail.com Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Analyzed-by: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Eric Biggers <ebiggers@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220111232309.1786347-1-surenb@google.com
2022-01-12cgroup: Fix cgroup_can_fork() and cgroup_post_fork() kernel-doc commentYang Li
Add the description of @kargs in cgroup_can_fork() and cgroup_post_fork() kernel-doc comment to remove warnings found by running scripts/kernel-doc, which is caused by using 'make W=1'. kernel/cgroup/cgroup.c:6235: warning: Function parameter or member 'kargs' not described in 'cgroup_can_fork' kernel/cgroup/cgroup.c:6296: warning: Function parameter or member 'kargs' not described in 'cgroup_post_fork' Reported-by: Abaci Robot <abaci@linux.alibaba.com> Signed-off-by: Yang Li <yang.lee@linux.alibaba.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2022-01-11Merge branch 'for-5.17' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: "Nothing too interesting. The only two noticeable changes are a subtle cpuset behavior fix and trace event id field being expanded to u64 from int. Most others are code cleanups" * 'for-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cpuset: convert 'allowed' in __cpuset_node_allowed() to be boolean cgroup/rstat: check updated_next only for root cgroup: rstat: explicitly put loop variant in while cgroup: return early if it is already on preloaded list cgroup/cpuset: Don't let child cpusets restrict parent in default hierarchy cgroup: Trace event cgroup id fields should be u64 cgroup: fix a typo in comment cgroup: get the wrong css for css_alloc() during cgroup_init_subsys() cgroup: rstat: Mark benign data race to silence KCSAN
2022-01-10Merge tag '5.17-net-next' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next Pull networking updates from Jakub Kicinski: "Core ---- - Defer freeing TCP skbs to the BH handler, whenever possible, or at least perform the freeing outside of the socket lock section to decrease cross-CPU allocator work and improve latency. - Add netdevice refcount tracking to locate sources of netdevice and net namespace refcount leaks. - Make Tx watchdog less intrusive - avoid pausing Tx and restarting all queues from a single CPU removing latency spikes. - Various small optimizations throughout the stack from Eric Dumazet. - Make netdev->dev_addr[] constant, force modifications to go via appropriate helpers to allow us to keep addresses in ordered data structures. - Replace unix_table_lock with per-hash locks, improving performance of bind() calls. - Extend skb drop tracepoint with a drop reason. - Allow SO_MARK and SO_PRIORITY setsockopt under CAP_NET_RAW. BPF --- - New helpers: - bpf_find_vma(), find and inspect VMAs for profiling use cases - bpf_loop(), runtime-bounded loop helper trading some execution time for much faster (if at all converging) verification - bpf_strncmp(), improve performance, avoid compiler flakiness - bpf_get_func_arg(), bpf_get_func_ret(), bpf_get_func_arg_cnt() for tracing programs, all inlined by the verifier - Support BPF relocations (CO-RE) in the kernel loader. - Further the support for BTF_TYPE_TAG annotations. - Allow access to local storage in sleepable helpers. - Convert verifier argument types to a composable form with different attributes which can be shared across types (ro, maybe-null). - Prepare libbpf for upcoming v1.0 release by cleaning up APIs, creating new, extensible ones where missing and deprecating those to be removed. Protocols --------- - WiFi (mac80211/cfg80211): - notify user space about long "come back in N" AP responses, allow it to react to such temporary rejections - allow non-standard VHT MCS 10/11 rates - use coarse time in airtime fairness code to save CPU cycles - Bluetooth: - rework of HCI command execution serialization to use a common queue and work struct, and improve handling errors reported in the middle of a batch of commands - rework HCI event handling to use skb_pull_data, avoiding packet parsing pitfalls - support AOSP Bluetooth Quality Report - SMC: - support net namespaces, following the RDMA model - improve connection establishment latency by pre-clearing buffers - introduce TCP ULP for automatic redirection to SMC - Multi-Path TCP: - support ioctls: SIOCINQ, OUTQ, and OUTQNSD - support socket options: IP_TOS, IP_FREEBIND, IP_TRANSPARENT, IPV6_FREEBIND, and IPV6_TRANSPARENT, TCP_CORK and TCP_NODELAY - support cmsgs: TCP_INQ - improvements in the data scheduler (assigning data to subflows) - support fastclose option (quick shutdown of the full MPTCP connection, similar to TCP RST in regular TCP) - MCTP (Management Component Transport) over serial, as defined by DMTF spec DSP0253 - "MCTP Serial Transport Binding". Driver API ---------- - Support timestamping on bond interfaces in active/passive mode. - Introduce generic phylink link mode validation for drivers which don't have any quirks and where MAC capability bits fully express what's supported. Allow PCS layer to participate in the validation. Convert a number of drivers. - Add support to set/get size of buffers on the Rx rings and size of the tx copybreak buffer via ethtool. - Support offloading TC actions as first-class citizens rather than only as attributes of filters, improve sharing and device resource utilization. - WiFi (mac80211/cfg80211): - support forwarding offload (ndo_fill_forward_path) - support for background radar detection hardware - SA Query Procedures offload on the AP side New hardware / drivers ---------------------- - tsnep - FPGA based TSN endpoint Ethernet MAC used in PLCs with real-time requirements for isochronous communication with protocols like OPC UA Pub/Sub. - Qualcomm BAM-DMUX WWAN - driver for data channels of modems integrated into many older Qualcomm SoCs, e.g. MSM8916 or MSM8974 (qcom_bam_dmux). - Microchip LAN966x multi-port Gigabit AVB/TSN Ethernet Switch driver with support for bridging, VLANs and multicast forwarding (lan966x). - iwlmei driver for co-operating between Intel's WiFi driver and Intel's Active Management Technology (AMT) devices. - mse102x - Vertexcom MSE102x Homeplug GreenPHY chips - Bluetooth: - MediaTek MT7921 SDIO devices - Foxconn MT7922A - Realtek RTL8852AE Drivers ------- - Significantly improve performance in the datapaths of: lan78xx, ax88179_178a, lantiq_xrx200, bnxt. - Intel Ethernet NICs: - igb: support PTP/time PEROUT and EXTTS SDP functions on 82580/i354/i350 adapters - ixgbevf: new PF -> VF mailbox API which avoids the risk of mailbox corruption with ESXi - iavf: support configuration of VLAN features of finer granularity, stacked tags and filtering - ice: PTP support for new E822 devices with sub-ns precision - ice: support firmware activation without reboot - Mellanox Ethernet NICs (mlx5): - expose control over IRQ coalescing mode (CQE vs EQE) via ethtool - support TC forwarding when tunnel encap and decap happen between two ports of the same NIC - dynamically size and allow disabling various features to save resources for running in embedded / SmartNIC scenarios - Broadcom Ethernet NICs (bnxt): - use page frag allocator to improve Rx performance - expose control over IRQ coalescing mode (CQE vs EQE) via ethtool - Other Ethernet NICs: - amd-xgbe: add Ryzen 6000 (Yellow Carp) Ethernet support - Microsoft cloud/virtual NIC (mana): - add XDP support (PASS, DROP, TX) - Mellanox Ethernet switches (mlxsw): - initial support for Spectrum-4 ASICs - VxLAN with IPv6 underlay - Marvell Ethernet switches (prestera): - support flower flow templates - add basic IP forwarding support - NXP embedded Ethernet switches (ocelot & felix): - support Per-Stream Filtering and Policing (PSFP) - enable cut-through forwarding between ports by default - support FDMA to improve packet Rx/Tx to CPU - Other embedded switches: - hellcreek: improve trapping management (STP and PTP) packets - qca8k: support link aggregation and port mirroring - Qualcomm 802.11ax WiFi (ath11k): - qca6390, wcn6855: enable 802.11 power save mode in station mode - BSS color change support - WCN6855 hw2.1 support - 11d scan offload support - scan MAC address randomization support - full monitor mode, only supported on QCN9074 - qca6390/wcn6855: report signal and tx bitrate - qca6390: rfkill support - qca6390/wcn6855: regdb.bin support - Intel WiFi (iwlwifi): - support SAR GEO Offset Mapping (SGOM) and Time-Aware-SAR (TAS) in cooperation with the BIOS - support for Optimized Connectivity Experience (OCE) scan - support firmware API version 68 - lots of preparatory work for the upcoming Bz device family - MediaTek WiFi (mt76): - Specific Absorption Rate (SAR) support - mt7921: 160 MHz channel support - RealTek WiFi (rtw88): - Specific Absorption Rate (SAR) support - scan offload - Other WiFi NICs - ath10k: support fetching (pre-)calibration data from nvmem - brcmfmac: configure keep-alive packet on suspend - wcn36xx: beacon filter support" * tag '5.17-net-next' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2048 commits) tcp: tcp_send_challenge_ack delete useless param `skb` net/qla3xxx: Remove useless DMA-32 fallback configuration rocker: Remove useless DMA-32 fallback configuration hinic: Remove useless DMA-32 fallback configuration lan743x: Remove useless DMA-32 fallback configuration net: enetc: Remove useless DMA-32 fallback configuration cxgb4vf: Remove useless DMA-32 fallback configuration cxgb4: Remove useless DMA-32 fallback configuration cxgb3: Remove useless DMA-32 fallback configuration bnx2x: Remove useless DMA-32 fallback configuration et131x: Remove useless DMA-32 fallback configuration be2net: Remove useless DMA-32 fallback configuration vmxnet3: Remove useless DMA-32 fallback configuration bna: Simplify DMA setting net: alteon: Simplify DMA setting myri10ge: Simplify DMA setting qlcnic: Simplify DMA setting net: allwinner: Fix print format page_pool: remove spinlock in page_pool_refill_alloc_cache() amt: fix wrong return type of amt_send_membership_update() ...
2022-01-06cgroup: Use open-time cgroup namespace for process migration perm checksTejun Heo
cgroup process migration permission checks are performed at write time as whether a given operation is allowed or not is dependent on the content of the write - the PID. This currently uses current's cgroup namespace which is a potential security weakness as it may allow scenarios where a less privileged process tricks a more privileged one into writing into a fd that it created. This patch makes cgroup remember the cgroup namespace at the time of open and uses it for migration permission checks instad of current's. Note that this only applies to cgroup2 as cgroup1 doesn't have namespace support. This also fixes a use-after-free bug on cgroupns reported in https://lore.kernel.org/r/00000000000048c15c05d0083397@google.com Note that backporting this fix also requires the preceding patch. Reported-by: "Eric W. Biederman" <ebiederm@xmission.com> Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Michal Koutný <mkoutny@suse.com> Reported-by: syzbot+50f5cf33a284ce738b62@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/00000000000048c15c05d0083397@google.com Fixes: 5136f6365ce3 ("cgroup: implement "nsdelegate" mount option") Signed-off-by: Tejun Heo <tj@kernel.org>
2022-01-06cgroup: Allocate cgroup_file_ctx for kernfs_open_file->privTejun Heo
of->priv is currently used by each interface file implementation to store private information. This patch collects the current two private data usages into struct cgroup_file_ctx which is allocated and freed by the common path. This allows generic private data which applies to multiple files, which will be used to in the following patch. Note that cgroup_procs iterator is now embedded as procs.iter in the new cgroup_file_ctx so that it doesn't need to be allocated and freed separately. v2: union dropped from cgroup_file_ctx and the procs iterator is embedded in cgroup_file_ctx as suggested by Linus. v3: Michal pointed out that cgroup1's procs pidlist uses of->priv too. Converted. Didn't change to embedded allocation as cgroup1 pidlists get stored for caching. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Michal Koutný <mkoutny@suse.com>
2022-01-06cgroup: Use open-time credentials for process migraton perm checksTejun Heo
cgroup process migration permission checks are performed at write time as whether a given operation is allowed or not is dependent on the content of the write - the PID. This currently uses current's credentials which is a potential security weakness as it may allow scenarios where a less privileged process tricks a more privileged one into writing into a fd that it created. This patch makes both cgroup2 and cgroup1 process migration interfaces to use the credentials saved at the time of open (file->f_cred) instead of current's. Reported-by: "Eric W. Biederman" <ebiederm@xmission.com> Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org> Fixes: 187fe84067bd ("cgroup: require write perm on common ancestor when moving processes on the default hierarchy") Reviewed-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-12-16add missing bpf-cgroup.h includesJakub Kicinski
We're about to break the cgroup-defs.h -> bpf-cgroup.h dependency, make sure those who actually need more than the definition of struct cgroup_bpf include bpf-cgroup.h explicitly. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/bpf/20211216025538.1649516-3-kuba@kernel.org
2021-12-14cgroup: return early if it is already on preloaded listWei Yang
If a cset is already on preloaded list, this means we have already setup this cset properly for migration. This patch just relocates the root cgrp lookup which isn't used anyway when the cset is already on the preloaded list. [tj@kernel.org: rephrase the commit log] Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-11-29cgroup: get the wrong css for css_alloc() during cgroup_init_subsys()Wei Yang
css_alloc() needs the parent css, while cgroup_css() gets current cgropu's css. So we are getting the wrong css during cgroup_init_subsys(). Fortunately, cgrp_dfl_root.cgrp's css is not set yet, so the value we pass to css_alloc() is NULL anyway. Let's pass NULL directly during init, since we know there is no parent yet. Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-11-02Merge branch 'for-5.16' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: - The misc controller now reports allocation rejections through misc.events instead of printking - cgroup_mutex usage is reduced to improve scalability of some operations - vhost helper threads are now assigned to the right cgroup on cgroup2 - Bug fixes * 'for-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: bpf: Move wrapper for __cgroup_bpf_*() to kernel/bpf/cgroup.c cgroup: Fix rootcg cpu.stat guest double counting cgroup: no need for cgroup_mutex for /proc/cgroups cgroup: remove cgroup_mutex from cgroupstats_build cgroup: reduce dependency on cgroup_mutex cgroup: cgroup-v1: do not exclude cgrp_dfl_root cgroup: Make rebind_subsystems() disable v2 controllers all at once docs/cgroup: add entry for misc.events misc_cgroup: remove error log to avoid log flood misc_cgroup: introduce misc.events to count failures
2021-11-01cgroup: bpf: Move wrapper for __cgroup_bpf_*() to kernel/bpf/cgroup.cHe Fengqing
In commit 324bda9e6c5a("bpf: multi program support for cgroup+bpf") cgroup_bpf_*() called from kernel/bpf/syscall.c, but now they are only used in kernel/bpf/cgroup.c, so move these function to kernel/bpf/cgroup.c, like cgroup_bpf_replace(). Signed-off-by: He Fengqing <hefengqing@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-10-25cgroup: reduce dependency on cgroup_mutexShakeel Butt
Currently cgroup_get_from_path() and cgroup_get_from_id() grab cgroup_mutex before traversing the default hierarchy to find the kernfs_node corresponding to the path/id and then extract the linked cgroup. Since cgroup_mutex is still held, it is guaranteed that the cgroup will be alive and the reference can be taken on it. However similar guarantee can be provided without depending on the cgroup_mutex and potentially reducing avenues of cgroup_mutex contentions. The kernfs_node's priv pointer is RCU protected pointer and with just rcu read lock we can grab the reference on the cgroup without cgroup_mutex. So, remove cgroup_mutex from them. Signed-off-by: Shakeel Butt <shakeelb@google.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-10-22cgroup: Fix memory leak caused by missing cgroup_bpf_offlineQuanyang Wang
When enabling CONFIG_CGROUP_BPF, kmemleak can be observed by running the command as below: $mount -t cgroup -o none,name=foo cgroup cgroup/ $umount cgroup/ unreferenced object 0xc3585c40 (size 64): comm "mount", pid 425, jiffies 4294959825 (age 31.990s) hex dump (first 32 bytes): 01 00 00 80 84 8c 28 c0 00 00 00 00 00 00 00 00 ......(......... 00 00 00 00 00 00 00 00 6c 43 a0 c3 00 00 00 00 ........lC...... backtrace: [<e95a2f9e>] cgroup_bpf_inherit+0x44/0x24c [<1f03679c>] cgroup_setup_root+0x174/0x37c [<ed4b0ac5>] cgroup1_get_tree+0x2c0/0x4a0 [<f85b12fd>] vfs_get_tree+0x24/0x108 [<f55aec5c>] path_mount+0x384/0x988 [<e2d5e9cd>] do_mount+0x64/0x9c [<208c9cfe>] sys_mount+0xfc/0x1f4 [<06dd06e0>] ret_fast_syscall+0x0/0x48 [<a8308cb3>] 0xbeb4daa8 This is because that since the commit 2b0d3d3e4fcf ("percpu_ref: reduce memory footprint of percpu_ref in fast path") root_cgrp->bpf.refcnt.data is allocated by the function percpu_ref_init in cgroup_bpf_inherit which is called by cgroup_setup_root when mounting, but not freed along with root_cgrp when umounting. Adding cgroup_bpf_offline which calls percpu_ref_kill to cgroup_kill_sb can free root_cgrp->bpf.refcnt.data in umount path. This patch also fixes the commit 4bfc0bb2c60e ("bpf: decouple the lifetime of cgroup_bpf from cgroup itself"). A cgroup_bpf_offline is needed to do a cleanup that frees the resources which are allocated by cgroup_bpf_inherit in cgroup_setup_root. And inside cgroup_bpf_offline, cgroup_get() is at the beginning and cgroup_put is at the end of cgroup_bpf_release which is called by cgroup_bpf_offline. So cgroup_bpf_offline can keep the balance of cgroup's refcount. Fixes: 2b0d3d3e4fcf ("percpu_ref: reduce memory footprint of percpu_ref in fast path") Fixes: 4bfc0bb2c60e ("bpf: decouple the lifetime of cgroup_bpf from cgroup itself") Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20211018075623.26884-1-quanyang.wang@windriver.com
2021-09-28bpf, cgroup: Assign cgroup in cgroup_sk_alloc when called from interruptDaniel Borkmann
If cgroup_sk_alloc() is called from interrupt context, then just assign the root cgroup to skcd->cgroup. Prior to commit 8520e224f547 ("bpf, cgroups: Fix cgroup v2 fallback on v1/v2 mixed mode") we would just return, and later on in sock_cgroup_ptr(), we were NULL-testing the cgroup in fast-path, and iff indeed NULL returning the root cgroup (v ?: &cgrp_dfl_root.cgrp). Rather than re-adding the NULL-test to the fast-path we can just assign it once from cgroup_sk_alloc() given v1/v2 handling has been simplified. The migration from NULL test with returning &cgrp_dfl_root.cgrp to assigning &cgrp_dfl_root.cgrp directly does /not/ change behavior for callers of sock_cgroup_ptr(). syzkaller was able to trigger a splat in the legacy netrom code base, where the RX handler in nr_rx_frame() calls nr_make_new() which calls sk_alloc() and therefore cgroup_sk_alloc() with in_interrupt() condition. Thus the NULL skcd->cgroup, where it trips over on cgroup_sk_free() side given it expects a non-NULL object. There are a few other candidates aside from netrom which have similar pattern where in their accept-like implementation, they just call to sk_alloc() and thus cgroup_sk_alloc() instead of sk_clone_lock() with the corresponding cgroup_sk_clone() which then inherits the cgroup from the parent socket. None of them are related to core protocols where BPF cgroup programs are running from. However, in future, they should follow to implement a similar inheritance mechanism. Additionally, with a !CONFIG_CGROUP_NET_PRIO and !CONFIG_CGROUP_NET_CLASSID configuration, the same issue was exposed also prior to 8520e224f547 due to commit e876ecc67db8 ("cgroup: memcg: net: do not associate sock with unrelated cgroup") which added the early in_interrupt() return back then. Fixes: 8520e224f547 ("bpf, cgroups: Fix cgroup v2 fallback on v1/v2 mixed mode") Fixes: e876ecc67db8 ("cgroup: memcg: net: do not associate sock with unrelated cgroup") Reported-by: syzbot+df709157a4ecaf192b03@syzkaller.appspotmail.com Reported-by: syzbot+533f389d4026d86a2a95@syzkaller.appspotmail.com Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Tested-by: syzbot+df709157a4ecaf192b03@syzkaller.appspotmail.com Tested-by: syzbot+533f389d4026d86a2a95@syzkaller.appspotmail.com Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/bpf/20210927123921.21535-1-daniel@iogearbox.net
2021-09-20cgroup: Make rebind_subsystems() disable v2 controllers all at onceWaiman Long
It was found that the following warning was displayed when remounting controllers from cgroup v2 to v1: [ 8042.997778] WARNING: CPU: 88 PID: 80682 at kernel/cgroup/cgroup.c:3130 cgroup_apply_control_disable+0x158/0x190 : [ 8043.091109] RIP: 0010:cgroup_apply_control_disable+0x158/0x190 [ 8043.096946] Code: ff f6 45 54 01 74 39 48 8d 7d 10 48 c7 c6 e0 46 5a a4 e8 7b 67 33 00 e9 41 ff ff ff 49 8b 84 24 e8 01 00 00 0f b7 40 08 eb 95 <0f> 0b e9 5f ff ff ff 48 83 c4 08 5b 5d 41 5c 41 5d 41 5e 41 5f c3 [ 8043.115692] RSP: 0018:ffffba8a47c23d28 EFLAGS: 00010202 [ 8043.120916] RAX: 0000000000000036 RBX: ffffffffa624ce40 RCX: 000000000000181a [ 8043.128047] RDX: ffffffffa63c43e0 RSI: ffffffffa63c43e0 RDI: ffff9d7284ee1000 [ 8043.135180] RBP: ffff9d72874c5800 R08: ffffffffa624b090 R09: 0000000000000004 [ 8043.142314] R10: ffffffffa624b080 R11: 0000000000002000 R12: ffff9d7284ee1000 [ 8043.149447] R13: ffff9d7284ee1000 R14: ffffffffa624ce70 R15: ffffffffa6269e20 [ 8043.156576] FS: 00007f7747cff740(0000) GS:ffff9d7a5fc00000(0000) knlGS:0000000000000000 [ 8043.164663] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 8043.170409] CR2: 00007f7747e96680 CR3: 0000000887d60001 CR4: 00000000007706e0 [ 8043.177539] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 8043.184673] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 8043.191804] PKRU: 55555554 [ 8043.194517] Call Trace: [ 8043.196970] rebind_subsystems+0x18c/0x470 [ 8043.201070] cgroup_setup_root+0x16c/0x2f0 [ 8043.205177] cgroup1_root_to_use+0x204/0x2a0 [ 8043.209456] cgroup1_get_tree+0x3e/0x120 [ 8043.213384] vfs_get_tree+0x22/0xb0 [ 8043.216883] do_new_mount+0x176/0x2d0 [ 8043.220550] __x64_sys_mount+0x103/0x140 [ 8043.224474] do_syscall_64+0x38/0x90 [ 8043.228063] entry_SYSCALL_64_after_hwframe+0x44/0xae It was caused by the fact that rebind_subsystem() disables controllers to be rebound one by one. If more than one disabled controllers are originally from the default hierarchy, it means that cgroup_apply_control_disable() will be called multiple times for the same default hierarchy. A controller may be killed by css_kill() in the first round. In the second round, the killed controller may not be completely dead yet leading to the warning. To avoid this problem, we collect all the ssid's of controllers that needed to be disabled from the default hierarchy and then disable them in one go instead of one by one. Fixes: 334c3679ec4b ("cgroup: reimplement rebind_subsystems() using cgroup_apply_control() and friends") Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-09-13bpf, cgroups: Fix cgroup v2 fallback on v1/v2 mixed modeDaniel Borkmann
Fix cgroup v1 interference when non-root cgroup v2 BPF programs are used. Back in the days, commit bd1060a1d671 ("sock, cgroup: add sock->sk_cgroup") embedded per-socket cgroup information into sock->sk_cgrp_data and in order to save 8 bytes in struct sock made both mutually exclusive, that is, when cgroup v1 socket tagging (e.g. net_cls/net_prio) is used, then cgroup v2 falls back to the root cgroup in sock_cgroup_ptr() (&cgrp_dfl_root.cgrp). The assumption made was "there is no reason to mix the two and this is in line with how legacy and v2 compatibility is handled" as stated in bd1060a1d671. However, with Kubernetes more widely supporting cgroups v2 as well nowadays, this assumption no longer holds, and the possibility of the v1/v2 mixed mode with the v2 root fallback being hit becomes a real security issue. Many of the cgroup v2 BPF programs are also used for policy enforcement, just to pick _one_ example, that is, to programmatically deny socket related system calls like connect(2) or bind(2). A v2 root fallback would implicitly cause a policy bypass for the affected Pods. In production environments, we have recently seen this case due to various circumstances: i) a different 3rd party agent and/or ii) a container runtime such as [0] in the user's environment configuring legacy cgroup v1 net_cls tags, which triggered implicitly mentioned root fallback. Another case is Kubernetes projects like kind [1] which create Kubernetes nodes in a container and also add cgroup namespaces to the mix, meaning programs which are attached to the cgroup v2 root of the cgroup namespace get attached to a non-root cgroup v2 path from init namespace point of view. And the latter's root is out of reach for agents on a kind Kubernetes node to configure. Meaning, any entity on the node setting cgroup v1 net_cls tag will trigger the bypass despite cgroup v2 BPF programs attached to the namespace root. Generally, this mutual exclusiveness does not hold anymore in today's user environments and makes cgroup v2 usage from BPF side fragile and unreliable. This fix adds proper struct cgroup pointer for the cgroup v2 case to struct sock_cgroup_data in order to address these issues; this implicitly also fixes the tradeoffs being made back then with regards to races and refcount leaks as stated in bd1060a1d671, and removes the fallback, so that cgroup v2 BPF programs always operate as expected. [0] https://github.com/nestybox/sysbox/ [1] https://kind.sigs.k8s.io/ Fixes: bd1060a1d671 ("sock, cgroup: add sock->sk_cgroup") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Stanislav Fomichev <sdf@google.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/bpf/20210913230759.2313-1-daniel@iogearbox.net