From 190ecb190a9cd8c0599d8499b901e3c32e87966a Mon Sep 17 00:00:00 2001 From: Qian Cai Date: Sun, 23 Feb 2020 22:00:07 -0500 Subject: cgroup: fix psi_show() crash on 32bit ino archs Similar to the commit d7495343228f ("cgroup: fix incorrect WARN_ON_ONCE() in cgroup_setup_root()"), cgroup_id(root_cgrp) does not equal to 1 on 32bit ino archs which triggers all sorts of issues with psi_show() on s390x. For example, BUG: KASAN: slab-out-of-bounds in collect_percpu_times+0x2d0/ Read of size 4 at addr 000000001e0ce000 by task read_all/3667 collect_percpu_times+0x2d0/0x798 psi_show+0x7c/0x2a8 seq_read+0x2ac/0x830 vfs_read+0x92/0x150 ksys_read+0xe2/0x188 system_call+0xd8/0x2b4 Fix it by using cgroup_ino(). Fixes: 743210386c03 ("cgroup: use cgrp->kn->id as the cgroup ID") Signed-off-by: Qian Cai Acked-by: Johannes Weiner Signed-off-by: Tejun Heo Cc: stable@vger.kernel.org # v5.5 --- kernel/cgroup/cgroup.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel/cgroup') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index c719a4154d6d..7a39dc882095 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -3542,21 +3542,21 @@ static int cpu_stat_show(struct seq_file *seq, void *v) static int cgroup_io_pressure_show(struct seq_file *seq, void *v) { struct cgroup *cgrp = seq_css(seq)->cgroup; - struct psi_group *psi = cgroup_id(cgrp) == 1 ? &psi_system : &cgrp->psi; + struct psi_group *psi = cgroup_ino(cgrp) == 1 ? &psi_system : &cgrp->psi; return psi_show(seq, psi, PSI_IO); } static int cgroup_memory_pressure_show(struct seq_file *seq, void *v) { struct cgroup *cgrp = seq_css(seq)->cgroup; - struct psi_group *psi = cgroup_id(cgrp) == 1 ? &psi_system : &cgrp->psi; + struct psi_group *psi = cgroup_ino(cgrp) == 1 ? &psi_system : &cgrp->psi; return psi_show(seq, psi, PSI_MEM); } static int cgroup_cpu_pressure_show(struct seq_file *seq, void *v) { struct cgroup *cgrp = seq_css(seq)->cgroup; - struct psi_group *psi = cgroup_id(cgrp) == 1 ? &psi_system : &cgrp->psi; + struct psi_group *psi = cgroup_ino(cgrp) == 1 ? &psi_system : &cgrp->psi; return psi_show(seq, psi, PSI_CPU); } -- cgit v1.2.3-58-ga151 From 2e5383d7904e60529136727e49629a82058a5607 Mon Sep 17 00:00:00 2001 From: Tycho Andersen Date: Wed, 19 Feb 2020 12:01:29 -0700 Subject: cgroup1: don't call release_agent when it is "" 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 --- kernel/cgroup/cgroup-v1.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/cgroup') diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c index 9a6f060cbf51..f2d7cea86ffe 100644 --- a/kernel/cgroup/cgroup-v1.c +++ b/kernel/cgroup/cgroup-v1.c @@ -783,7 +783,7 @@ void cgroup1_release_agent(struct work_struct *work) pathbuf = kmalloc(PATH_MAX, GFP_KERNEL); agentbuf = kstrdup(cgrp->root->release_agent_path, GFP_KERNEL); - if (!pathbuf || !agentbuf) + if (!pathbuf || !agentbuf || !strlen(agentbuf)) goto out; spin_lock_irq(&css_set_lock); -- cgit v1.2.3-58-ga151