cgroup: rstat: call cgroup_rstat_updated_list with cgroup_rstat_lock

The commit 093c8812de2d ("cgroup: rstat: Cleanup flushing functions and
locking") during cleanup accidentally changed the code to call
cgroup_rstat_updated_list() without cgroup_rstat_lock which is required.
Fix it.

Fixes: 093c8812de2d ("cgroup: rstat: Cleanup flushing functions and locking")
Reported-by: Jakub Kicinski <kuba@kernel.org>
Reported-by: Breno Leitao <leitao@debian.org>
Reported-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Closes: https://lore.kernel.org/all/6564c3d6-9372-4352-9847-1eb3aea07ca4@linux.ibm.com/
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index 4bb587d5d34f976166148491e6f9c75417ff6e3a..b2239156b7def9bc8d796d3b5af9915b59c5a21c 100644 (file)
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -318,10 +318,11 @@ __bpf_kfunc void cgroup_rstat_flush(struct cgroup *cgrp)
 
        might_sleep();
        for_each_possible_cpu(cpu) {
-               struct cgroup *pos = cgroup_rstat_updated_list(cgrp, cpu);
+               struct cgroup *pos;
 
                /* Reacquire for each CPU to avoid disabling IRQs too long */
                __cgroup_rstat_lock(cgrp, cpu);
+               pos = cgroup_rstat_updated_list(cgrp, cpu);
                for (; pos; pos = pos->rstat_flush_next) {
                        struct cgroup_subsys_state *css;