From: Tahsin Erdogan <tahsin@xxxxxxxxxx>
Subject: mm: do not call mem_cgroup_free() from within mem_cgroup_alloc()
mem_cgroup_free() indirectly calls wb_domain_exit() which is not prepared
to deal with a struct wb_domain object that hasn't executed
wb_domain_init(). For instance, the following warning message is printed
by lockdep if alloc_percpu() fails in mem_cgroup_alloc():
INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 1 PID: 1950 Comm: mkdir Not tainted 4.10.0+ #151
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
dump_stack+0x67/0x99
register_lock_class+0x36d/0x540
__lock_acquire+0x7f/0x1a30
? irq_work_queue+0x73/0x90
? wake_up_klogd+0x36/0x40
? console_unlock+0x45d/0x540
? vprintk_emit+0x211/0x2e0
lock_acquire+0xcc/0x200
? try_to_del_timer_sync+0x60/0x60
del_timer_sync+0x3c/0xc0
? try_to_del_timer_sync+0x60/0x60
wb_domain_exit+0x14/0x20
mem_cgroup_free+0x14/0x40
mem_cgroup_css_alloc+0x3f9/0x620
cgroup_apply_control_enable+0x190/0x390
cgroup_mkdir+0x290/0x3d0
kernfs_iop_mkdir+0x58/0x80
vfs_mkdir+0x10e/0x1a0
SyS_mkdirat+0xa8/0xd0
SyS_mkdir+0x14/0x20
entry_SYSCALL_64_fastpath+0x18/0xad
Add __mem_cgroup_free() which skips wb_domain_exit(). This is used by
both mem_cgroup_free() and mem_cgroup_alloc() clean up.
Fixes: 0b8f73e104285 ("mm: memcontrol: clean up alloc, online, offline, free functions")
Link: http://lkml.kernel.org/r/20170306192122.24262-1-tahsin@xxxxxxxxxx
Signed-off-by: Tahsin Erdogan <tahsin@xxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff -puN mm/memcontrol.c~mm-do-not-call-mem_cgroup_free-from-within-mem_cgroup_alloc mm/memcontrol.c
--- a/mm/memcontrol.c~mm-do-not-call-mem_cgroup_free-from-within-mem_cgroup_alloc
+++ a/mm/memcontrol.c
@@ -4138,17 +4138,22 @@ static void free_mem_cgroup_per_node_inf
kfree(memcg->nodeinfo[node]);
}
-static void mem_cgroup_free(struct mem_cgroup *memcg)
+static void __mem_cgroup_free(struct mem_cgroup *memcg)
{
int node;
- memcg_wb_domain_exit(memcg);
for_each_node(node)
free_mem_cgroup_per_node_info(memcg, node);
free_percpu(memcg->stat);
kfree(memcg);
}
+static void mem_cgroup_free(struct mem_cgroup *memcg)
+{
+ memcg_wb_domain_exit(memcg);
+ __mem_cgroup_free(memcg);
+}
+
static struct mem_cgroup *mem_cgroup_alloc(void)
{
struct mem_cgroup *memcg;
@@ -4199,7 +4204,7 @@ static struct mem_cgroup *mem_cgroup_all
fail:
if (memcg->id.id > 0)
idr_remove(&mem_cgroup_idr, memcg->id.id);
- mem_cgroup_free(memcg);
+ __mem_cgroup_free(memcg);
return NULL;
}
_
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