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2021-11-06Merge branch 'akpm' (patches from Andrew)Linus Torvalds1-0/+23
Merge misc updates from Andrew Morton: "257 patches. Subsystems affected by this patch series: scripts, ocfs2, vfs, and mm (slab-generic, slab, slub, kconfig, dax, kasan, debug, pagecache, gup, swap, memcg, pagemap, mprotect, mremap, iomap, tracing, vmalloc, pagealloc, memory-failure, hugetlb, userfaultfd, vmscan, tools, memblock, oom-kill, hugetlbfs, migration, thp, readahead, nommu, ksm, vmstat, madvise, memory-hotplug, rmap, zsmalloc, highmem, zram, cleanups, kfence, and damon)" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (257 commits) mm/damon: remove return value from before_terminate callback mm/damon: fix a few spelling mistakes in comments and a pr_debug message mm/damon: simplify stop mechanism Docs/admin-guide/mm/pagemap: wordsmith page flags descriptions Docs/admin-guide/mm/damon/start: simplify the content Docs/admin-guide/mm/damon/start: fix a wrong link Docs/admin-guide/mm/damon/start: fix wrong example commands mm/damon/dbgfs: add adaptive_targets list check before enable monitor_on mm/damon: remove unnecessary variable initialization Documentation/admin-guide/mm/damon: add a document for DAMON_RECLAIM mm/damon: introduce DAMON-based Reclamation (DAMON_RECLAIM) selftests/damon: support watermarks mm/damon/dbgfs: support watermarks mm/damon/schemes: activate schemes based on a watermarks mechanism tools/selftests/damon: update for regions prioritization of schemes mm/damon/dbgfs: support prioritization weights mm/damon/vaddr,paddr: support pageout prioritization mm/damon/schemes: prioritize regions within the quotas mm/damon/selftests: support schemes quotas mm/damon/dbgfs: support quotas of schemes ...
2021-11-06mm/page_alloc: detect allocation forbidden by cpuset and bail out earlyFeng Tang1-0/+23
There was a report that starting an Ubuntu in docker while using cpuset to bind it to movable nodes (a node only has movable zone, like a node for hotplug or a Persistent Memory node in normal usage) will fail due to memory allocation failure, and then OOM is involved and many other innocent processes got killed. It can be reproduced with command: $ docker run -it --rm --cpuset-mems 4 ubuntu:latest bash -c "grep Mems_allowed /proc/self/status" (where node 4 is a movable node) runc:[2:INIT] invoked oom-killer: gfp_mask=0x500cc2(GFP_HIGHUSER|__GFP_ACCOUNT), order=0, oom_score_adj=0 CPU: 8 PID: 8291 Comm: runc:[2:INIT] Tainted: G W I E 5.8.2-0.g71b519a-default #1 openSUSE Tumbleweed (unreleased) Hardware name: Dell Inc. PowerEdge R640/0PHYDR, BIOS 2.6.4 04/09/2020 Call Trace: dump_stack+0x6b/0x88 dump_header+0x4a/0x1e2 oom_kill_process.cold+0xb/0x10 out_of_memory.part.0+0xaf/0x230 out_of_memory+0x3d/0x80 __alloc_pages_slowpath.constprop.0+0x954/0xa20 __alloc_pages_nodemask+0x2d3/0x300 pipe_write+0x322/0x590 new_sync_write+0x196/0x1b0 vfs_write+0x1c3/0x1f0 ksys_write+0xa7/0xe0 do_syscall_64+0x52/0xd0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Mem-Info: active_anon:392832 inactive_anon:182 isolated_anon:0 active_file:68130 inactive_file:151527 isolated_file:0 unevictable:2701 dirty:0 writeback:7 slab_reclaimable:51418 slab_unreclaimable:116300 mapped:45825 shmem:735 pagetables:2540 bounce:0 free:159849484 free_pcp:73 free_cma:0 Node 4 active_anon:1448kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB all_unreclaimable? no Node 4 Movable free:130021408kB min:9140kB low:139160kB high:269180kB reserved_highatomic:0KB active_anon:1448kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:130023424kB managed:130023424kB mlocked:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:292kB local_pcp:84kB free_cma:0kB lowmem_reserve[]: 0 0 0 0 0 Node 4 Movable: 1*4kB (M) 0*8kB 0*16kB 1*32kB (M) 0*64kB 0*128kB 1*256kB (M) 1*512kB (M) 1*1024kB (M) 0*2048kB 31743*4096kB (M) = 130021156kB oom-kill:constraint=CONSTRAINT_CPUSET,nodemask=(null),cpuset=docker-9976a269caec812c134fa317f27487ee36e1129beba7278a463dd53e5fb9997b.scope,mems_allowed=4,global_oom,task_memcg=/system.slice/containerd.service,task=containerd,pid=4100,uid=0 Out of memory: Killed process 4100 (containerd) total-vm:4077036kB, anon-rss:51184kB, file-rss:26016kB, shmem-rss:0kB, UID:0 pgtables:676kB oom_score_adj:0 oom_reaper: reaped process 8248 (docker), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB oom_reaper: reaped process 2054 (node_exporter), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB oom_reaper: reaped process 1452 (systemd-journal), now anon-rss:0kB, file-rss:8564kB, shmem-rss:4kB oom_reaper: reaped process 2146 (munin-node), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB oom_reaper: reaped process 8291 (runc:[2:INIT]), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB The reason is that in this case, the target cpuset nodes only have movable zone, while the creation of an OS in docker sometimes needs to allocate memory in non-movable zones (dma/dma32/normal) like GFP_HIGHUSER, and the cpuset limit forbids the allocation, then out-of-memory killing is involved even when normal nodes and movable nodes both have many free memory. The OOM killer cannot help to resolve the situation as there is no usable memory for the request in the cpuset scope. The only reasonable measure to take is to fail the allocation right away and have the caller to deal with it. So add a check for cases like this in the slowpath of allocation, and bail out early returning NULL for the allocation. As page allocation is one of the hottest path in kernel, this check will hurt all users with sane cpuset configuration, add a static branch check and detect the abnormal config in cpuset memory binding setup so that the extra check cost in page allocation is not paid by everyone. [thanks to Micho Hocko and David Rientjes for suggesting not handling it inside OOM code, adding cpuset check, refining comments] Link: https://lkml.kernel.org/r/1632481657-68112-1-git-send-email-feng.tang@intel.com Signed-off-by: Feng Tang <feng.tang@intel.com> Suggested-by: Michal Hocko <mhocko@suse.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Rientjes <rientjes@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Zefan Li <lizefan.x@bytedance.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-11-02Merge branch 'for-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroupLinus Torvalds4-86/+84
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 Fengqing1-38/+0
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>
2021-11-01cgroup: Fix rootcg cpu.stat guest double countingDan Schatzberg1-2/+0
In account_guest_time in kernel/sched/cputime.c guest time is attributed to both CPUTIME_NICE and CPUTIME_USER in addition to CPUTIME_GUEST_NICE and CPUTIME_GUEST respectively. Therefore, adding both to calculate usage results in double counting any guest time at the rootcg. Fixes: 936f2a70f207 ("cgroup: add cpu.stat file to root cgroup") Signed-off-by: Dan Schatzberg <schatzberg.dan@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-10-25cgroup: no need for cgroup_mutex for /proc/cgroupsShakeel Butt1-5/+2
On the real systems, the cgroups hierarchies are setup early and just once by the node controller, so, other than number of cgroups, all information in /proc/cgroups remain same for the system uptime. Let's remove the cgroup_mutex usage on reading /proc/cgroups. There is a chance of inconsistent number of cgroups for co-mounted cgroups while printing the information from /proc/cgroups but that is not a big issue. In addition /proc/cgroups is a v1 specific interface, so the dependency on it should reduce over time. The main motivation for removing the cgroup_mutex from /proc/cgroups is to reduce the avenues of its contention. On our fleet, we have observed buggy application hammering on /proc/cgroups and drastically slowing down the node controller on the system which have many negative consequences on other workloads running on the system. Signed-off-by: Shakeel Butt <shakeelb@google.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-10-25cgroup: remove cgroup_mutex from cgroupstats_buildShakeel Butt1-5/+2
The function cgroupstats_build extracts cgroup from the kernfs_node's priv pointer which is a RCU pointer. So, there is no need to grab cgroup_mutex. Just get the reference on the cgroup before using and remove the cgroup_mutex altogether. Signed-off-by: Shakeel Butt <shakeelb@google.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-10-25cgroup: reduce dependency on cgroup_mutexShakeel Butt1-22/+29
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 Wang1-1/+3
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
2021-10-11Merge branch 'for-5.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroupLinus Torvalds1-27/+29
Pull cgroup fixes from Tejun Heo: "All documentation / comment updates" * 'for-5.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroupv2, docs: fix misinformation in "device controller" section cgroup/cpuset: Change references of cpuset_mutex to cpuset_rwsem docs/cgroup: remove some duplicate words
2021-10-05cgroup: cgroup-v1: do not exclude cgrp_dfl_rootVishal Verma1-3/+0
Found an issue within cgroup_attach_task_all() fn which seem to exclude cgrp_dfl_root (cgroupv2) while attaching tasks to the given cgroup. This was noticed when the system was running qemu/kvm with kernel vhost helper threads. It appears that the vhost layer which uses cgroup_attach_task_all() fn to assign the vhost kthread to the right qemu cgroup works fine with cgroupv1 based configuration but not in cgroupv2. With cgroupv2, the vhost helper thread ends up just belonging to the root cgroup as is shown below: $ stat -fc %T /sys/fs/cgroup/ cgroup2fs $ sudo pgrep qemu 1916421 $ ps -eL | grep 1916421 1916421 1916421 ? 00:00:01 qemu-system-x86 1916421 1916431 ? 00:00:00 call_rcu 1916421 1916435 ? 00:00:00 IO mon_iothread 1916421 1916436 ? 00:00:34 CPU 0/KVM 1916421 1916439 ? 00:00:00 SPICE Worker 1916421 1916440 ? 00:00:00 vnc_worker 1916433 1916433 ? 00:00:00 vhost-1916421 1916437 1916437 ? 00:00:00 kvm-pit/1916421 $ cat /proc/1916421/cgroup 0::/machine.slice/machine-qemu\x2d18\x2dDroplet\x2d7572850.scope/emulator $ cat /proc/1916439/cgroup 0::/machine.slice/machine-qemu\x2d18\x2dDroplet\x2d7572850.scope/emulator $ cat /proc/1916433/cgroup 0::/ From above, it can be seen that the vhost kthread (PID: 1916433) doesn't seem to belong the qemu cgroup like other qemu PIDs. After applying this patch: $ pgrep qemu 1643 $ ps -eL | grep 1643 1643 1643 ? 00:00:00 qemu-system-x86 1643 1645 ? 00:00:00 call_rcu 1643 1648 ? 00:00:00 IO mon_iothread 1643 1649 ? 00:00:00 CPU 0/KVM 1643 1652 ? 00:00:00 SPICE Worker 1643 1653 ? 00:00:00 vnc_worker 1647 1647 ? 00:00:00 vhost-1643 1651 1651 ? 00:00:00 kvm-pit/1643 $ cat /proc/1647/cgroup 0::/machine.slice/machine-qemu\x2d18\x2dDroplet\x2d7572850.scope/emulator Suggested-by: Tejun Heo <tj@kernel.org> Signed-off-by: Vishal Verma <vverma@digitalocean.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-09-28bpf, cgroup: Assign cgroup in cgroup_sk_alloc when called from interruptDaniel Borkmann1-5/+12
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 Long1-4/+27
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>
2021-09-20misc_cgroup: remove error log to avoid log floodChunguang Xu1-7/+0
In scenarios where containers are frequently created and deleted, a large number of error logs maybe generated. The logs only show which node is about to go over the max limit, not the node which resource request failed. As misc.events has provided relevant information, maybe we can remove this log. Signed-off-by: Chunguang Xu <brookxu@tencent.com> Reviewed-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-09-20misc_cgroup: introduce misc.events to count failuresChunguang Xu1-0/+24
Introduce misc.events to make it easier for us to understand the pressure of resources. Currently only the 'max' event is implemented, which indicates the times the resource is about to exceeds the max limit. Signed-off-by: Chunguang Xu <brookxu@tencent.com> Reviewed-by: Vipin Sharma <vipinsh@google.com> Reviewed-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-09-14Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpfDavid S. Miller1-40/+10
Daniel Borkmann says: ==================== pull-request: bpf 2021-09-14 The following pull-request contains BPF updates for your *net* tree. We've added 7 non-merge commits during the last 13 day(s) which contain a total of 18 files changed, 334 insertions(+), 193 deletions(-). The main changes are: 1) Fix mmap_lock lockdep splat in BPF stack map's build_id lookup, from Yonghong Song. 2) Fix BPF cgroup v2 program bypass upon net_cls/prio activation, from Daniel Borkmann. 3) Fix kvcalloc() BTF line info splat on oversized allocation attempts, from Bixuan Cui. 4) Fix BPF selftest build of task_pt_regs test for arm64/s390, from Jean-Philippe Brucker. 5) Fix BPF's disasm.{c,h} to dual-license so that it is aligned with bpftool given the former is a build dependency for the latter, from Daniel Borkmann with ACKs from contributors. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-13bpf, cgroups: Fix cgroup v2 fallback on v1/v2 mixed modeDaniel Borkmann1-40/+10
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
2021-09-13cgroup/cpuset: Change references of cpuset_mutex to cpuset_rwsemWaiman Long1-27/+29
Since commit 1243dc518c9d ("cgroup/cpuset: Convert cpuset_mutex to percpu_rwsem"), cpuset_mutex has been replaced by cpuset_rwsem which is a percpu rwsem. However, the comments in kernel/cgroup/cpuset.c still reference cpuset_mutex which are now incorrect. Change all the references of cpuset_mutex to cpuset_rwsem. Fixes: 1243dc518c9d ("cgroup/cpuset: Convert cpuset_mutex to percpu_rwsem") Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-09-03Merge branch 'akpm' (patches from Andrew)Linus Torvalds1-1/+1
Merge misc updates from Andrew Morton: "173 patches. Subsystems affected by this series: ia64, ocfs2, block, and mm (debug, pagecache, gup, swap, shmem, memcg, selftests, pagemap, mremap, bootmem, sparsemem, vmalloc, kasan, pagealloc, memory-failure, hugetlb, userfaultfd, vmscan, compaction, mempolicy, memblock, oom-kill, migration, ksm, percpu, vmstat, and madvise)" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (173 commits) mm/madvise: add MADV_WILLNEED to process_madvise() mm/vmstat: remove unneeded return value mm/vmstat: simplify the array size calculation mm/vmstat: correct some wrong comments mm/percpu,c: remove obsolete comments of pcpu_chunk_populated() selftests: vm: add COW time test for KSM pages selftests: vm: add KSM merging time test mm: KSM: fix data type selftests: vm: add KSM merging across nodes test selftests: vm: add KSM zero page merging test selftests: vm: add KSM unmerge test selftests: vm: add KSM merge test mm/migrate: correct kernel-doc notation mm: wire up syscall process_mrelease mm: introduce process_mrelease system call memblock: make memblock_find_in_range method private mm/mempolicy.c: use in_task() in mempolicy_slab_node() mm/mempolicy: unify the create() func for bind/interleave/prefer-many policies mm/mempolicy: advertise new MPOL_PREFERRED_MANY mm/hugetlb: add support for mempolicy MPOL_PREFERRED_MANY ...
2021-09-03memcg: enable accounting for new namesapces and struct nsproxyVasily Averin1-1/+1
Container admin can create new namespaces and force kernel to allocate up to several pages of memory for the namespaces and its associated structures. Net and uts namespaces have enabled accounting for such allocations. It makes sense to account for rest ones to restrict the host's memory consumption from inside the memcg-limited container. Link: https://lkml.kernel.org/r/5525bcbf-533e-da27-79b7-158686c64e13@virtuozzo.com Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Acked-by: Serge Hallyn <serge@hallyn.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: Kirill Tkhai <ktkhai@virtuozzo.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrei Vagin <avagin@gmail.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Dmitry Safonov <0x7f454c46@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Jeff Layton <jlayton@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Roman Gushchin <guro@fb.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Yutian Yang <nglaive@gmail.com> Cc: Zefan Li <lizefan.x@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-08-31Merge branch 'for-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroupLinus Torvalds3-64/+133
Pull cgroup updates from Tejun Heo: "Two cpuset behavior changes: - cpuset on cgroup2 is changed to enable memory migration based on nodemask by default. - A notification is generated when cpuset partition state changes. All other patches are minor fixes and cleanups" * 'for-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: Avoid compiler warnings with no subsystems cgroup/cpuset: Avoid memory migration when nodemasks match cgroup/cpuset: Enable memory migration for cpuset v2 cgroup/cpuset: Enable event notification when partition state changes cgroup: cgroup-v1: clean up kernel-doc notation cgroup: Replace deprecated CPU-hotplug functions. cgroup/cpuset: Fix violation of cpuset locking rule cgroup/cpuset: Fix a partition bug with hotplug cgroup/cpuset: Miscellaneous code cleanup cgroup: remove cgroup_mount from comments
2021-08-30Merge tag 'sched-core-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds1-20/+39
Pull scheduler updates from Ingo Molnar: - The biggest change in this cycle is scheduler support for asymmetric scheduling affinity, to support the execution of legacy 32-bit tasks on AArch32 systems that also have 64-bit-only CPUs. Architectures can fill in this functionality by defining their own task_cpu_possible_mask(p). When this is done, the scheduler will make sure the task will only be scheduled on CPUs that support it. (The actual arm64 specific changes are not part of this tree.) For other architectures there will be no change in functionality. - Add cgroup SCHED_IDLE support - Increase node-distance flexibility & delay determining it until a CPU is brought online. (This enables platforms where node distance isn't final until the CPU is only.) - Deadline scheduler enhancements & fixes - Misc fixes & cleanups. * tag 'sched-core-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits) eventfd: Make signal recursion protection a task bit sched/fair: Mark tg_is_idle() an inline in the !CONFIG_FAIR_GROUP_SCHED case sched: Introduce dl_task_check_affinity() to check proposed affinity sched: Allow task CPU affinity to be restricted on asymmetric systems sched: Split the guts of sched_setaffinity() into a helper function sched: Introduce task_struct::user_cpus_ptr to track requested affinity sched: Reject CPU affinity changes based on task_cpu_possible_mask() cpuset: Cleanup cpuset_cpus_allowed_fallback() use in select_fallback_rq() cpuset: Honour task_cpu_possible_mask() in guarantee_online_cpus() cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1 sched: Introduce task_cpu_possible_mask() to limit fallback rq selection sched: Cgroup SCHED_IDLE support sched/topology: Skip updating masks for non-online nodes sched: Replace deprecated CPU-hotplug functions. sched: Skip priority checks with SCHED_FLAG_KEEP_PARAMS sched: Fix UCLAMP_FLAG_IDLE setting sched/deadline: Fix missing clock update in migrate_task_rq_dl() sched/fair: Avoid a second scan of target in select_idle_cpu sched/fair: Use prev instead of new target as recent_used_cpu sched: Don't report SCHED_FLAG_SUGOV in sched_getattr() ...
2021-08-30cgroup: Avoid compiler warnings with no subsystemsKees Cook1-6/+20
As done before in commit cb4a31675270 ("cgroup: use bitmask to filter for_each_subsys"), avoid compiler warnings for the pathological case of having no subsystems (i.e. CGROUP_SUBSYS_COUNT == 0). This condition is hit for the arm multi_v7_defconfig config under -Wzero-length-bounds: In file included from ./arch/arm/include/generated/asm/rwonce.h:1, from include/linux/compiler.h:264, from include/uapi/linux/swab.h:6, from include/linux/swab.h:5, from arch/arm/include/asm/opcodes.h:86, from arch/arm/include/asm/bug.h:7, from include/linux/bug.h:5, from include/linux/thread_info.h:13, from include/asm-generic/current.h:5, from ./arch/arm/include/generated/asm/current.h:1, from include/linux/sched.h:12, from include/linux/cgroup.h:12, from kernel/cgroup/cgroup-internal.h:5, from kernel/cgroup/cgroup.c:31: kernel/cgroup/cgroup.c: In function 'of_css': kernel/cgroup/cgroup.c:651:42: warning: array subscript '<unknown>' is outside the bounds of an interior zero-length array 'struct cgroup_subsys_state *[0]' [-Wzero-length-bounds] 651 | return rcu_dereference_raw(cgrp->subsys[cft->ss->id]); Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Tejun Heo <tj@kernel.org> Cc: Zefan Li <lizefan.x@bytedance.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: cgroups@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-08-25cgroup/cpuset: Avoid memory migration when nodemasks matchNicolas Saenz Julienne1-0/+5
With the introduction of ee9707e8593d ("cgroup/cpuset: Enable memory migration for cpuset v2") attaching a process to a different cgroup will trigger a memory migration regardless of whether it's really needed. Memory migration is an expensive operation, so bypass it if the nodemasks passed to cpuset_migrate_mm() are equal. Note that we're not only avoiding the migration work itself, but also a call to lru_cache_disable(), which triggers and flushes an LRU drain work on every online CPU. Signed-off-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-08-20cpuset: Cleanup cpuset_cpus_allowed_fallback() use in select_fallback_rq()Will Deacon1-2/+8
select_fallback_rq() only needs to recheck for an allowed CPU if the affinity mask of the task has changed since the last check. Return a 'bool' from cpuset_cpus_allowed_fallback() to indicate whether the affinity mask was updated, and use this to elide the allowed check when the mask has been left alone. No functional change. Suggested-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Valentin Schneider <valentin.schneider@arm.com> Link: https://lore.kernel.org/r/20210730112443.23245-5-will@kernel.org
2021-08-20cpuset: Honour task_cpu_possible_mask() in guarantee_online_cpus()Will Deacon1-17/+26
Asymmetric systems may not offer the same level of userspace ISA support across all CPUs, meaning that some applications cannot be executed by some CPUs. As a concrete example, upcoming arm64 big.LITTLE designs do not feature support for 32-bit applications on both clusters. Modify guarantee_online_cpus() to take task_cpu_possible_mask() into account when trying to find a suitable set of online CPUs for a given task. This will avoid passing an invalid mask to set_cpus_allowed_ptr() during ->attach() and will subsequently allow the cpuset hierarchy to be taken into account when forcefully overriding the affinity mask for a task which requires migration to a compatible CPU. Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Valentin Schneider <Valentin.Schneider@arm.com> Link: https://lkml.kernel.org/r/20210730112443.23245-4-will@kernel.org
2021-08-20cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1Will Deacon1-2/+6
If the scheduler cannot find an allowed CPU for a task, cpuset_cpus_allowed_fallback() will widen the affinity to cpu_possible_mask if cgroup v1 is in use. In preparation for allowing architectures to provide their own fallback mask, just return early if we're either using cgroup v1 or we're using cgroup v2 with a mask that contains invalid CPUs. This will allow select_fallback_rq() to figure out the mask by itself. Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Valentin Schneider <valentin.schneider@arm.com> Reviewed-by: Quentin Perret <qperret@google.com> Link: https://lkml.kernel.org/r/20210730112443.23245-3-will@kernel.org
2021-08-12cgroup/cpuset: Enable memory migration for cpuset v2Waiman Long1-1/+5
When a user changes cpuset.cpus, each task in a v2 cpuset will be moved to one of the new cpus if it is not there already. For memory, however, they won't be migrated to the new nodes when cpuset.mems changes. This is an inconsistency in behavior. In cpuset v1, there is a memory_migrate control file to enable such behavior by setting the CS_MEMORY_MIGRATE flag. Make it the default for cpuset v2 so that we have a consistent set of behavior for both cpus and memory. There is certainly a cost to make memory migration the default, but it is a one time cost that shouldn't really matter as long as cpuset.mems isn't changed frequenty. Update the cgroup-v2.rst file to document the new behavior and recommend against changing cpuset.mems frequently. Since there won't be any concurrent access to the newly allocated cpuset structure in cpuset_css_alloc(), we can use the cheaper non-atomic __set_bit() instead of the more expensive atomic set_bit(). Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-08-11cgroup/cpuset: Enable event notification when partition state changesWaiman Long1-11/+35
A valid cpuset partition can become invalid if all its CPUs are offlined or somehow removed. This can happen through external events without "cpuset.cpus.partition" being touched at all. Users that rely on the property of a partition being present do not currently have a simple way to get such an event notified other than constant periodic polling which is both inefficient and cumbersome. To make life easier for those users, event notification is now enabled for "cpuset.cpus.partition" whenever its state changes. Suggested-by: Tejun Heo <tj@kernel.org> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-08-11cgroup: cgroup-v1: clean up kernel-doc notationRandy Dunlap1-1/+7
Fix kernel-doc warnings found in cgroup-v1.c: kernel/cgroup/cgroup-v1.c:55: warning: No description found for return value of 'cgroup_attach_task_all' kernel/cgroup/cgroup-v1.c:94: warning: expecting prototype for cgroup_trasnsfer_tasks(). Prototype was for cgroup_transfer_tasks() instead cgroup-v1.c:96: warning: No description found for return value of 'cgroup_transfer_tasks' kernel/cgroup/cgroup-v1.c:687: warning: No description found for return value of 'cgroupstats_build' Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Zefan Li <lizefan.x@bytedance.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: cgroups@vger.kernel.org Signed-off-by: Tejun Heo <tj@kernel.org>
2021-08-09cgroup: Replace deprecated CPU-hotplug functions.Sebastian Andrzej Siewior1-15/+15
The functions get_online_cpus() and put_online_cpus() have been deprecated during the CPU hotplug rework. They map directly to cpus_read_lock() and cpus_read_unlock(). Replace deprecated CPU-hotplug functions with the official version. The behavior remains unchanged. Cc: Zefan Li <lizefan.x@bytedance.com> Cc: Tejun Heo <tj@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: cgroups@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-08-09cgroup/cpuset: Fix violation of cpuset locking ruleWaiman Long1-23/+35
The cpuset fields that manage partition root state do not strictly follow the cpuset locking rule that update to cpuset has to be done with both the callback_lock and cpuset_mutex held. This is now fixed by making sure that the locking rule is upheld. Fixes: 3881b86128d0 ("cpuset: Add an error state to cpuset.sched.partition") Fixes: 4b842da276a8 ("cpuset: Make CPU hotplug work with partition") Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-07-27cgroup: rstat: fix A-A deadlock on 32bit around u64_stats_syncTejun Heo1-8/+11
0fa294fb1985 ("cgroup: Replace cgroup_rstat_mutex with a spinlock") added cgroup_rstat_flush_irqsafe() allowing flushing to happen from the irq context. However, rstat paths use u64_stats_sync to synchronize access to 64bit stat counters on 32bit machines. u64_stats_sync is implemented using seq_lock and trying to read from an irq context can lead to A-A deadlock if the irq happens to interrupt the stat update. Fix it by using the irqsafe variants - u64_stats_update_begin_irqsave() and u64_stats_update_end_irqrestore() - in the update paths. Note that none of this matters on 64bit machines. All these are just for 32bit SMP setups. Note that the interface was introduced way back, its first and currently only use was recently added by 2d146aa3aa84 ("mm: memcontrol: switch to rstat"). Stable tagging targets this commit. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Rik van Riel <riel@surriel.com> Fixes: 2d146aa3aa84 ("mm: memcontrol: switch to rstat") Cc: stable@vger.kernel.org # v5.13+
2021-07-26cgroup/cpuset: Fix a partition bug with hotplugWaiman Long1-0/+7
In cpuset_hotplug_workfn(), the detection of whether the cpu list has been changed is done by comparing the effective cpus of the top cpuset with the cpu_active_mask. However, in the rare case that just all the CPUs in the subparts_cpus are offlined, the detection fails and the partition states are not updated correctly. Fix it by forcing the cpus_updated flag to true in this particular case. Fixes: 4b842da276a8 ("cpuset: Make CPU hotplug work with partition") Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-07-26cgroup/cpuset: Miscellaneous code cleanupWaiman Long1-21/+19
Use more descriptive variable names for update_prstate(), remove unnecessary code and fix some typos. There is no functional change. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-07-21cgroup1: fix leaked context root causing sporadic NULL deref in LTPPaul Gortmaker1-3/+1
Richard reported sporadic (roughly one in 10 or so) null dereferences and other strange behaviour for a set of automated LTP tests. Things like: BUG: kernel NULL pointer dereference, address: 0000000000000008 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 0 PID: 1516 Comm: umount Not tainted 5.10.0-yocto-standard #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-48-gd9c812dda519-prebuilt.qemu.org 04/01/2014 RIP: 0010:kernfs_sop_show_path+0x1b/0x60 ...or these others: RIP: 0010:do_mkdirat+0x6a/0xf0 RIP: 0010:d_alloc_parallel+0x98/0x510 RIP: 0010:do_readlinkat+0x86/0x120 There were other less common instances of some kind of a general scribble but the common theme was mount and cgroup and a dubious dentry triggering the NULL dereference. I was only able to reproduce it under qemu by replicating Richard's setup as closely as possible - I never did get it to happen on bare metal, even while keeping everything else the same. In commit 71d883c37e8d ("cgroup_do_mount(): massage calling conventions") we see this as a part of the overall change: -------------- struct cgroup_subsys *ss; - struct dentry *dentry; [...] - dentry = cgroup_do_mount(&cgroup_fs_type, fc->sb_flags, root, - CGROUP_SUPER_MAGIC, ns); [...] - if (percpu_ref_is_dying(&root->cgrp.self.refcnt)) { - struct super_block *sb = dentry->d_sb; - dput(dentry); + ret = cgroup_do_mount(fc, CGROUP_SUPER_MAGIC, ns); + if (!ret && percpu_ref_is_dying(&root->cgrp.self.refcnt)) { + struct super_block *sb = fc->root->d_sb; + dput(fc->root); deactivate_locked_super(sb); msleep(10); return restart_syscall(); } -------------- In changing from the local "*dentry" variable to using fc->root, we now export/leave that dentry pointer in the file context after doing the dput() in the unlikely "is_dying" case. With LTP doing a crazy amount of back to back mount/unmount [testcases/bin/cgroup_regression_5_1.sh] the unlikely becomes slightly likely and then bad things happen. A fix would be to not leave the stale reference in fc->root as follows: --------------                 dput(fc->root); + fc->root = NULL;                 deactivate_locked_super(sb); -------------- ...but then we are just open-coding a duplicate of fc_drop_locked() so we simply use that instead. Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Tejun Heo <tj@kernel.org> Cc: Zefan Li <lizefan.x@bytedance.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: stable@vger.kernel.org # v5.1+ Reported-by: Richard Purdie <richard.purdie@linuxfoundation.org> Fixes: 71d883c37e8d ("cgroup_do_mount(): massage calling conventions") Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-07-16cgroup: remove cgroup_mount from commentszhaoxiaoqiang111-1/+0
Git rid of an outdated comment. Since cgroup was fully switched to fs_context, cgroup_mount() is gone and it's confusing to mention in comments of cgroup_kill_sb(). Delete it. Signed-off-by: zhaoxiaoqiang11 <zhaoxiaoqiang11@jd.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-07-14fs: add vfs_parse_fs_param_source() helperChristian Brauner1-9/+5
Add a simple helper that filesystems can use in their parameter parser to parse the "source" parameter. A few places open-coded this function and that already caused a bug in the cgroup v1 parser that we fixed. Let's make it harder to get this wrong by introducing a helper which performs all necessary checks. Link: https://syzkaller.appspot.com/bug?id=6312526aba5beae046fdae8f00399f87aab48b12 Cc: Christoph Hellwig <hch@lst.de> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-14cgroup: verify that source is a stringChristian Brauner1-0/+2
The following sequence can be used to trigger a UAF: int fscontext_fd = fsopen("cgroup"); int fd_null = open("/dev/null, O_RDONLY); int fsconfig(fscontext_fd, FSCONFIG_SET_FD, "source", fd_null); close_range(3, ~0U, 0); The cgroup v1 specific fs parser expects a string for the "source" parameter. However, it is perfectly legitimate to e.g. specify a file descriptor for the "source" parameter. The fs parser doesn't know what a filesystem allows there. So it's a bug to assume that "source" is always of type fs_value_is_string when it can reasonably also be fs_value_is_file. This assumption in the cgroup code causes a UAF because struct fs_parameter uses a union for the actual value. Access to that union is guarded by the param->type member. Since the cgroup paramter parser didn't check param->type but unconditionally moved param->string into fc->source a close on the fscontext_fd would trigger a UAF during put_fs_context() which frees fc->source thereby freeing the file stashed in param->file causing a UAF during a close of the fd_null. Fix this by verifying that param->type is actually a string and report an error if not. In follow up patches I'll add a new generic helper that can be used here and by other filesystems instead of this error-prone copy-pasta fix. But fixing it in here first makes backporting a it to stable a lot easier. Fixes: 8d2451f4994f ("cgroup1: switch to option-by-option parsing") Reported-by: syzbot+283ce5a46486d6acdbaf@syzkaller.appspotmail.com Cc: Christoph Hellwig <hch@lst.de> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: <stable@kernel.org> Cc: syzkaller-bugs <syzkaller-bugs@googlegroups.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-02Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsiLinus Torvalds1-0/+25
Pull SCSI updates from James Bottomley: "This series consists of the usual driver updates (ufs, ibmvfc, megaraid_sas, lpfc, elx, mpi3mr, qedi, iscsi, storvsc, mpt3sas) with elx and mpi3mr being new drivers. The major core change is a rework to drop the status byte handling macros and the old bit shifted definitions and the rest of the updates are minor fixes" * tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (287 commits) scsi: aha1740: Avoid over-read of sense buffer scsi: arcmsr: Avoid over-read of sense buffer scsi: ips: Avoid over-read of sense buffer scsi: ufs: ufs-mediatek: Add missing of_node_put() in ufs_mtk_probe() scsi: elx: libefc: Fix IRQ restore in efc_domain_dispatch_frame() scsi: elx: libefc: Fix less than zero comparison of a unsigned int scsi: elx: efct: Fix pointer error checking in debugfs init scsi: elx: efct: Fix is_originator return code type scsi: elx: efct: Fix link error for _bad_cmpxchg scsi: elx: efct: Eliminate unnecessary boolean check in efct_hw_command_cancel() scsi: elx: efct: Do not use id uninitialized in efct_lio_setup_session() scsi: elx: efct: Fix error handling in efct_hw_init() scsi: elx: efct: Remove redundant initialization of variable lun scsi: elx: efct: Fix spelling mistake "Unexected" -> "Unexpected" scsi: lpfc: Fix build error in lpfc_scsi.c scsi: target: iscsi: Remove redundant continue statement scsi: qla4xxx: Remove redundant continue statement scsi: ppa: Switch to use module_parport_driver() scsi: imm: Switch to use module_parport_driver() scsi: mpt3sas: Fix error return value in _scsih_expander_add() ...
2021-07-01Merge branch 'for-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroupLinus Torvalds2-17/+165
Pull cgroup updates from Tejun Heo: - cgroup.kill is added which implements atomic killing of the whole subtree. Down the line, this should be able to replace the multiple userland implementations of "keep killing till empty". - PSI can now be turned off at boot time to avoid overhead for configurations which don't care about PSI. * 'for-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: make per-cgroup pressure stall tracking configurable cgroup: Fix kernel-doc cgroup: inline cgroup_task_freeze() tests/cgroup: test cgroup.kill tests/cgroup: move cg_wait_for(), cg_prepare_for_wait() tests/cgroup: use cgroup.kill in cg_killall() docs/cgroup: add entry for cgroup.kill cgroup: introduce cgroup.kill
2021-06-29Merge branch 'akpm' (patches from Andrew)Linus Torvalds1-0/+1
Merge misc updates from Andrew Morton: "191 patches. Subsystems affected by this patch series: kthread, ia64, scripts, ntfs, squashfs, ocfs2, kernel/watchdog, and mm (gup, pagealloc, slab, slub, kmemleak, dax, debug, pagecache, gup, swap, memcg, pagemap, mprotect, bootmem, dma, tracing, vmalloc, kasan, initialization, pagealloc, and memory-failure)" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (191 commits) mm,hwpoison: make get_hwpoison_page() call get_any_page() mm,hwpoison: send SIGBUS with error virutal address mm/page_alloc: split pcp->high across all online CPUs for cpuless nodes mm/page_alloc: allow high-order pages to be stored on the per-cpu lists mm: replace CONFIG_FLAT_NODE_MEM_MAP with CONFIG_FLATMEM mm: replace CONFIG_NEED_MULTIPLE_NODES with CONFIG_NUMA docs: remove description of DISCONTIGMEM arch, mm: remove stale mentions of DISCONIGMEM mm: remove CONFIG_DISCONTIGMEM m68k: remove support for DISCONTIGMEM arc: remove support for DISCONTIGMEM arc: update comment about HIGHMEM implementation alpha: remove DISCONTIGMEM and NUMA mm/page_alloc: move free_the_page mm/page_alloc: fix counting of managed_pages mm/page_alloc: improve memmap_pages dbg msg mm: drop SECTION_SHIFT in code comments mm/page_alloc: introduce vm.percpu_pagelist_high_fraction mm/page_alloc: limit the number of pages on PCP lists when reclaim is active mm/page_alloc: scale the number of pages that are batch freed ...
2021-06-29loop: charge i/o to mem and blk cgDan Schatzberg1-0/+1
The current code only associates with the existing blkcg when aio is used to access the backing file. This patch covers all types of i/o to the backing file and also associates the memcg so if the backing file is on tmpfs, memory is charged appropriately. This patch also exports cgroup_get_e_css and int_active_memcg so it can be used by the loop module. Link: https://lkml.kernel.org/r/20210610173944.1203706-4-schatzberg.dan@gmail.com Signed-off-by: Dan Schatzberg <schatzberg.dan@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Jens Axboe <axboe@kernel.dk> Cc: Chris Down <chris@chrisdown.name> Cc: Michal Hocko <mhocko@suse.com> Cc: Ming Lei <ming.lei@redhat.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-18sched: Change task_struct::statePeter Zijlstra1-1/+1
Change the type and name of task_struct::state. Drop the volatile and shrink it to an 'unsigned int'. Rename it in order to find all uses such that we can use READ_ONCE/WRITE_ONCE as appropriate. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com> Acked-by: Will Deacon <will@kernel.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20210611082838.550736351@infradead.org
2021-06-10scsi: cgroup: Add cgroup_get_from_id()Muneendra Kumar1-0/+26
Add a new function, cgroup_get_from_id(), to retrieve the cgroup associated with a cgroup id. Also export the function cgroup_get_e_css() as this is needed in blk-cgroup.h. Link: https://lore.kernel.org/r/20210608043556.274139-2-muneendra.kumar@broadcom.com Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Muneendra Kumar <muneendra.kumar@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2021-06-10cgroup1: don't allow '\n' in renamingAlexander Kuznetsov1-0/+4
cgroup_mkdir() have restriction on newline usage in names: $ mkdir $'/sys/fs/cgroup/cpu/test\ntest2' mkdir: cannot create directory '/sys/fs/cgroup/cpu/test\ntest2': Invalid argument But in cgroup1_rename() such check is missed. This allows us to make /proc/<pid>/cgroup unparsable: $ mkdir /sys/fs/cgroup/cpu/test $ mv /sys/fs/cgroup/cpu/test $'/sys/fs/cgroup/cpu/test\ntest2' $ echo $$ > $'/sys/fs/cgroup/cpu/test\ntest2' $ cat /proc/self/cgroup 11:pids:/ 10:freezer:/ 9:hugetlb:/ 8:cpuset:/ 7:blkio:/user.slice 6:memory:/user.slice 5:net_cls,net_prio:/ 4:perf_event:/ 3:devices:/user.slice 2:cpu,cpuacct:/test test2 1:name=systemd:/ 0::/ Signed-off-by: Alexander Kuznetsov <wwfq@yandex-team.ru> Reported-by: Andrey Krasichkov <buglloc@yandex-team.ru> Acked-by: Dmitry Yakunin <zeil@yandex-team.ru> Cc: stable@vger.kernel.org Signed-off-by: Tejun Heo <tj@kernel.org>
2021-06-08cgroup: make per-cgroup pressure stall tracking configurableSuren Baghdasaryan1-0/+48
PSI accounts stalls for each cgroup separately and aggregates it at each level of the hierarchy. This causes additional overhead with psi_avgs_work being called for each cgroup in the hierarchy. psi_avgs_work has been highly optimized, however on systems with large number of cgroups the overhead becomes noticeable. Systems which use PSI only at the system level could avoid this overhead if PSI can be configured to skip per-cgroup stall accounting. Add "cgroup_disable=pressure" kernel command-line option to allow requesting system-wide only pressure stall accounting. When set, it keeps system-wide accounting under /proc/pressure/ but skips accounting for individual cgroups and does not expose PSI nodes in cgroup hierarchy. Signed-off-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-06-04cgroup: Fix kernel-docYang Li2-2/+2
Fix function name in cgroup.c and rstat.c kernel-doc comment to remove these warnings found by clang_w1. kernel/cgroup/cgroup.c:2401: warning: expecting prototype for cgroup_taskset_migrate(). Prototype was for cgroup_migrate_execute() instead. kernel/cgroup/rstat.c:233: warning: expecting prototype for cgroup_rstat_flush_begin(). Prototype was for cgroup_rstat_flush_hold() instead. Reported-by: Abaci Robot <abaci@linux.alibaba.com> Fixes: 'commit e595cd706982 ("cgroup: track migration context in cgroup_mgctx")' Signed-off-by: Yang Li <yang.lee@linux.alibaba.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-05-24Merge branch 'for-5.13-fixes' into for-5.14Tejun Heo5-16/+13
2021-05-24cgroup: fix spelling mistakesZhen Lei5-8/+8
Fix some spelling mistakes in comments: hierarhcy ==> hierarchy automtically ==> automatically overriden ==> overridden In absense of .. or ==> In absence of .. and assocaited ==> associated taget ==> target initate ==> initiate succeded ==> succeeded curremt ==> current udpated ==> updated Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>