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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
   lock_acquire+0xcc/0x200
   del_timer_sync+0x3c/0xc0
   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: 0b8f73e104 ("mm: memcontrol: clean up alloc, online, offline, free functions")
Link: http://lkml.kernel.org/r/20170306192122.24262-1-tahsin@google.com
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Tahsin Erdogan 2017-03-09 16:17:26 -08:00 committed by Linus Torvalds
parent 6ebb4a1b84
commit 40e952f9d6
1 changed files with 8 additions and 3 deletions
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11
mm/memcontrol.c
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@ -4138,17 +4138,22 @@ static void free_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
kfree(memcg->nodeinfo[node]); kfree(memcg->nodeinfo[node]);
} }
static void mem_cgroup_free(struct mem_cgroup *memcg) static void __mem_cgroup_free(struct mem_cgroup *memcg)
{ {
int node; int node;
memcg_wb_domain_exit(memcg);
for_each_node(node) for_each_node(node)
free_mem_cgroup_per_node_info(memcg, node); free_mem_cgroup_per_node_info(memcg, node);
free_percpu(memcg->stat); free_percpu(memcg->stat);
kfree(memcg); 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) static struct mem_cgroup *mem_cgroup_alloc(void)
{ {
struct mem_cgroup *memcg; struct mem_cgroup *memcg;
@ -4199,7 +4204,7 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
fail: fail:
if (memcg->id.id > 0) if (memcg->id.id > 0)
idr_remove(&mem_cgroup_idr, memcg->id.id); idr_remove(&mem_cgroup_idr, memcg->id.id);
mem_cgroup_free(memcg); __mem_cgroup_free(memcg);
return NULL; return NULL;
} }