user/sven/linux.git/kernel/cgroup, branch v5.4.111

cgroup: fix psi monitor for root cgroup

2021-02-17T09:35:14Z

commit 385aac1519417b89cb91b77c22e4ca21db563cd0 upstream. Fix NULL pointer dereference when adding new psi monitor to the root cgroup. PSI files for root cgroup was introduced in df5ba5be742 by using system wide psi struct when reading, but file write/monitor was not properly fixed. Since the PSI config for the root cgroup isn't initialized, the current implementation tries to lock a NULL ptr, resulting in a crash. Can be triggered by running this as root: $ tee /sys/fs/cgroup/cpu.pressure <<< "some 10000 1000000" Signed-off-by: Odin Ugedal Reviewed-by: Suren Baghdasaryan Acked-by: Dan Schatzberg Fixes: df5ba5be7425 ("kernel/sched/psi.c: expose pressure metrics on root cgroup") Acked-by: Johannes Weiner Cc: stable@vger.kernel.org # 5.2+ Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

cgroup: Fix memory leak when parsing multiple source parameters

2021-01-06T13:48:37Z

commit 2d18e54dd8662442ef5898c6bdadeaf90b3cebbc upstream. A memory leak is found in cgroup1_parse_param() when multiple source parameters overwrite fc->source in the fs_context struct without free. unreferenced object 0xffff888100d930e0 (size 16): comm "mount", pid 520, jiffies 4303326831 (age 152.783s) hex dump (first 16 bytes): 74 65 73 74 6c 65 61 6b 00 00 00 00 00 00 00 00 testleak........ backtrace: [<000000003e5023ec>] kmemdup_nul+0x2d/0xa0 [<00000000377dbdaa>] vfs_parse_fs_string+0xc0/0x150 [<00000000cb2b4882>] generic_parse_monolithic+0x15a/0x1d0 [<000000000f750198>] path_mount+0xee1/0x1820 [<0000000004756de2>] do_mount+0xea/0x100 [<0000000094cafb0a>] __x64_sys_mount+0x14b/0x1f0 Fix this bug by permitting a single source parameter and rejecting with an error all subsequent ones. Fixes: 8d2451f4994f ("cgroup1: switch to option-by-option parsing") Reported-by: Hulk Robot Signed-off-by: Qinglang Miao Reviewed-by: Zefan Li Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

cpuset: fix race between hotplug work and later CPU offline

2020-12-30T10:51:36Z

commit 406100f3da08066c00105165db8520bbc7694a36 upstream. One of our machines keeled over trying to rebuild the scheduler domains. Mainline produces the same splat: BUG: unable to handle page fault for address: 0000607f820054db CPU: 2 PID: 149 Comm: kworker/1:1 Not tainted 5.10.0-rc1-master+ #6 Workqueue: events cpuset_hotplug_workfn RIP: build_sched_domains Call Trace: partition_sched_domains_locked rebuild_sched_domains_locked cpuset_hotplug_workfn It happens with cgroup2 and exclusive cpusets only. This reproducer triggers it on an 8-cpu vm and works most effectively with no preexisting child cgroups: cd $UNIFIED_ROOT mkdir cg1 echo 4-7 > cg1/cpuset.cpus echo root > cg1/cpuset.cpus.partition # with smt/control reading 'on', echo off > /sys/devices/system/cpu/smt/control RIP maps to sd->shared = *per_cpu_ptr(sdd->sds, sd_id); from sd_init(). sd_id is calculated earlier in the same function: cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); sd_id = cpumask_first(sched_domain_span(sd)); tl->mask(cpu), which reads cpu_sibling_map on x86, returns an empty mask and so cpumask_first() returns >= nr_cpu_ids, which leads to the bogus value from per_cpu_ptr() above. The problem is a race between cpuset_hotplug_workfn() and a later offline of CPU N. cpuset_hotplug_workfn() updates the effective masks when N is still online, the offline clears N from cpu_sibling_map, and then the worker uses the stale effective masks that still have N to generate the scheduling domains, leading the worker to read N's empty cpu_sibling_map in sd_init(). rebuild_sched_domains_locked() prevented the race during the cgroup2 cpuset series up until the Fixes commit changed its check. Make the check more robust so that it can detect an offline CPU in any exclusive cpuset's effective mask, not just the top one. Fixes: 0ccea8feb980 ("cpuset: Make generate_sched_domains() work with partition") Signed-off-by: Daniel Jordan Signed-off-by: Peter Zijlstra (Intel) Acked-by: Tejun Heo Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20201112171711.639541-1-daniel.m.jordan@oracle.com Signed-off-by: Greg Kroah-Hartman

cgroup: fix cgroup_sk_alloc() for sk_clone_lock()

2020-07-22T07:32:49Z

[ Upstream commit ad0f75e5f57ccbceec13274e1e242f2b5a6397ed ] When we clone a socket in sk_clone_lock(), its sk_cgrp_data is copied, so the cgroup refcnt must be taken too. And, unlike the sk_alloc() path, sock_update_netprioidx() is not called here. Therefore, it is safe and necessary to grab the cgroup refcnt even when cgroup_sk_alloc is disabled. sk_clone_lock() is in BH context anyway, the in_interrupt() would terminate this function if called there. And for sk_alloc() skcd->val is always zero. So it's safe to factor out the code to make it more readable. The global variable 'cgroup_sk_alloc_disabled' is used to determine whether to take these reference counts. It is impossible to make the reference counting correct unless we save this bit of information in skcd->val. So, add a new bit there to record whether the socket has already taken the reference counts. This obviously relies on kmalloc() to align cgroup pointers to at least 4 bytes, ARCH_KMALLOC_MINALIGN is certainly larger than that. This bug seems to be introduced since the beginning, commit d979a39d7242 ("cgroup: duplicate cgroup reference when cloning sockets") tried to fix it but not compeletely. It seems not easy to trigger until the recent commit 090e28b229af ("netprio_cgroup: Fix unlimited memory leak of v2 cgroups") was merged. Fixes: bd1060a1d671 ("sock, cgroup: add sock->sk_cgroup") Reported-by: Cameron Berkenpas Reported-by: Peter Geis Reported-by: Lu Fengqi Reported-by: Daniël Sonck Reported-by: Zhang Qiang Tested-by: Cameron Berkenpas Tested-by: Peter Geis Tested-by: Thomas Lamprecht Cc: Daniel Borkmann Cc: Zefan Li Cc: Tejun Heo Cc: Roman Gushchin Signed-off-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

Revert "cgroup: Add memory barriers to plug cgroup_rstat_updated() race window"

2020-06-07T11:18:46Z

[ Upstream commit d8ef4b38cb69d907f9b0e889c44d05fc0f890977 ] This reverts commit 9a9e97b2f1f2 ("cgroup: Add memory barriers to plug cgroup_rstat_updated() race window"). The commit was added in anticipation of memcg rstat conversion which needed synchronous accounting for the event counters (e.g. oom kill count). However, the conversion didn't get merged due to percpu memory overhead concern which couldn't be addressed at the time. Unfortunately, the patch's addition of smp_mb() to cgroup_rstat_updated() meant that every scheduling event now had to go through an additional full barrier and Mel Gorman noticed it as 1% regression in netperf UDP_STREAM test. There's no need to have this barrier in tree now and even if we need synchronous accounting in the future, the right thing to do is separating that out to a separate function so that hot paths which don't care about synchronous behavior don't have to pay the overhead of the full barrier. Let's revert. Signed-off-by: Tejun Heo Reported-by: Mel Gorman Link: http://lkml.kernel.org/r/20200409154413.GK3818@techsingularity.net Cc: v4.18+ Signed-off-by: Sasha Levin

cgroup1: don't call release_agent when it is ""

2020-04-01T09:01:51Z

[ Upstream commit 2e5383d7904e60529136727e49629a82058a5607 ] Older (and maybe current) versions of systemd set release_agent to "" when shutting down, but do not set notify_on_release to 0. Since 64e90a8acb85 ("Introduce STATIC_USERMODEHELPER to mediate call_usermodehelper()"), we filter out such calls when the user mode helper path is "". However, when used in conjunction with an actual (i.e. non "") STATIC_USERMODEHELPER, the path is never "", so the real usermode helper will be called with argv[0] == "". Let's avoid this by not invoking the release_agent when it is "". Signed-off-by: Tycho Andersen Signed-off-by: Tejun Heo Signed-off-by: Sasha Levin

cgroup-v1: cgroup_pidlist_next should update position index

2020-04-01T09:01:50Z

[ Upstream commit db8dd9697238be70a6b4f9d0284cd89f59c0e070 ] if seq_file .next fuction does not change position index, read after some lseek can generate unexpected output. # mount | grep cgroup # dd if=/mnt/cgroup.procs bs=1 # normal output ... 1294 1295 1296 1304 1382 584+0 records in 584+0 records out 584 bytes copied dd: /mnt/cgroup.procs: cannot skip to specified offset 83 <<< generates end of last line 1383 <<< ... and whole last line once again 0+1 records in 0+1 records out 8 bytes copied dd: /mnt/cgroup.procs: cannot skip to specified offset 1386 <<< generates last line anyway 0+1 records in 0+1 records out 5 bytes copied https://bugzilla.kernel.org/show_bug.cgi?id=206283 Signed-off-by: Vasily Averin Signed-off-by: Tejun Heo Signed-off-by: Sasha Levin

cgroup: Iterate tasks that did not finish do_exit()

2020-03-18T06:17:48Z

commit 9c974c77246460fa6a92c18554c3311c8c83c160 upstream. PF_EXITING is set earlier than actual removal from css_set when a task is exitting. This can confuse cgroup.procs readers who see no PF_EXITING tasks, however, rmdir is checking against css_set membership so it can transitionally fail with EBUSY. Fix this by listing tasks that weren't unlinked from css_set active lists. It may happen that other users of the task iterator (without CSS_TASK_ITER_PROCS) spot a PF_EXITING task before cgroup_exit(). This is equal to the state before commit c03cd7738a83 ("cgroup: Include dying leaders with live threads in PROCS iterations") but it may be reviewed later. Reported-by: Suren Baghdasaryan Fixes: c03cd7738a83 ("cgroup: Include dying leaders with live threads in PROCS iterations") Signed-off-by: Michal Koutný Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

cgroup: cgroup_procs_next should increase position index

2020-03-18T06:17:48Z

commit 2d4ecb030dcc90fb725ecbfc82ce5d6c37906e0e upstream. If seq_file .next fuction does not change position index, read after some lseek can generate unexpected output: 1) dd bs=1 skip output of each 2nd elements $ dd if=/sys/fs/cgroup/cgroup.procs bs=8 count=1 2 3 4 5 1+0 records in 1+0 records out 8 bytes copied, 0,000267297 s, 29,9 kB/s [test@localhost ~]$ dd if=/sys/fs/cgroup/cgroup.procs bs=1 count=8 2 4 <<< NB! 3 was skipped 6 <<< ... and 5 too 8 <<< ... and 7 8+0 records in 8+0 records out 8 bytes copied, 5,2123e-05 s, 153 kB/s This happen because __cgroup_procs_start() makes an extra extra cgroup_procs_next() call 2) read after lseek beyond end of file generates whole last line. 3) read after lseek into middle of last line generates expected rest of last line and unexpected whole line once again. Additionally patch removes an extra position index changes in __cgroup_procs_start() Cc: stable@vger.kernel.org https://bugzilla.kernel.org/show_bug.cgi?id=206283 Signed-off-by: Vasily Averin Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

cgroup: memcg: net: do not associate sock with unrelated cgroup

2020-03-18T06:17:43Z

[ Upstream commit e876ecc67db80dfdb8e237f71e5b43bb88ae549c ] We are testing network memory accounting in our setup and noticed inconsistent network memory usage and often unrelated cgroups network usage correlates with testing workload. On further inspection, it seems like mem_cgroup_sk_alloc() and cgroup_sk_alloc() are broken in irq context specially for cgroup v1. mem_cgroup_sk_alloc() and cgroup_sk_alloc() can be called in irq context and kind of assumes that this can only happen from sk_clone_lock() and the source sock object has already associated cgroup. However in cgroup v1, where network memory accounting is opt-in, the source sock can be unassociated with any cgroup and the new cloned sock can get associated with unrelated interrupted cgroup. Cgroup v2 can also suffer if the source sock object was created by process in the root cgroup or if sk_alloc() is called in irq context. The fix is to just do nothing in interrupt. WARNING: Please note that about half of the TCP sockets are allocated from the IRQ context, so, memory used by such sockets will not be accouted by the memcg. The stack trace of mem_cgroup_sk_alloc() from IRQ-context: CPU: 70 PID: 12720 Comm: ssh Tainted: 5.6.0-smp-DEV #1 Hardware name: ... Call Trace: dump_stack+0x57/0x75 mem_cgroup_sk_alloc+0xe9/0xf0 sk_clone_lock+0x2a7/0x420 inet_csk_clone_lock+0x1b/0x110 tcp_create_openreq_child+0x23/0x3b0 tcp_v6_syn_recv_sock+0x88/0x730 tcp_check_req+0x429/0x560 tcp_v6_rcv+0x72d/0xa40 ip6_protocol_deliver_rcu+0xc9/0x400 ip6_input+0x44/0xd0 ? ip6_protocol_deliver_rcu+0x400/0x400 ip6_rcv_finish+0x71/0x80 ipv6_rcv+0x5b/0xe0 ? ip6_sublist_rcv+0x2e0/0x2e0 process_backlog+0x108/0x1e0 net_rx_action+0x26b/0x460 __do_softirq+0x104/0x2a6 do_softirq_own_stack+0x2a/0x40 do_softirq.part.19+0x40/0x50 __local_bh_enable_ip+0x51/0x60 ip6_finish_output2+0x23d/0x520 ? ip6table_mangle_hook+0x55/0x160 __ip6_finish_output+0xa1/0x100 ip6_finish_output+0x30/0xd0 ip6_output+0x73/0x120 ? __ip6_finish_output+0x100/0x100 ip6_xmit+0x2e3/0x600 ? ipv6_anycast_cleanup+0x50/0x50 ? inet6_csk_route_socket+0x136/0x1e0 ? skb_free_head+0x1e/0x30 inet6_csk_xmit+0x95/0xf0 __tcp_transmit_skb+0x5b4/0xb20 __tcp_send_ack.part.60+0xa3/0x110 tcp_send_ack+0x1d/0x20 tcp_rcv_state_process+0xe64/0xe80 ? tcp_v6_connect+0x5d1/0x5f0 tcp_v6_do_rcv+0x1b1/0x3f0 ? tcp_v6_do_rcv+0x1b1/0x3f0 __release_sock+0x7f/0xd0 release_sock+0x30/0xa0 __inet_stream_connect+0x1c3/0x3b0 ? prepare_to_wait+0xb0/0xb0 inet_stream_connect+0x3b/0x60 __sys_connect+0x101/0x120 ? __sys_getsockopt+0x11b/0x140 __x64_sys_connect+0x1a/0x20 do_syscall_64+0x51/0x200 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The stack trace of mem_cgroup_sk_alloc() from IRQ-context: Fixes: 2d7580738345 ("mm: memcontrol: consolidate cgroup socket tracking") Fixes: d979a39d7242 ("cgroup: duplicate cgroup reference when cloning sockets") Signed-off-by: Shakeel Butt Reviewed-by: Roman Gushchin Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman