cgroup: fix psi_show() crash on 32bit ino archs (190ecb19) · Commits · 戴 / test

Similar to the commit ("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: ("cgroup: use cgrp->kn->id as the cgroup ID") Signed-off-by:

Qian Cai <cai@lca.pw> Acked-by:

Johannes Weiner <hannes@cmpxchg.org> Signed-off-by:

Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org # v5.5

kernel/cgroup/cgroup.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -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);
		}

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