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authorMike Galbraith <umgwanakikbuti@gmail.com>2014-06-21 10:09:48 +0200
committerAnders Roxell <anders.roxell@linaro.org>2015-06-01 12:03:36 +0200
commitf71519b1494aaa73ce1dcbb5b751e58fa4bd8904 (patch)
tree90adf2d4a77dd7b9f286bf91a221bb6435e27d9f
parentea9dff6b6282ac5a79496f6886d25b89c10ec2a5 (diff)
downloadlinux-linaro-stable-f71519b1494aaa73ce1dcbb5b751e58fa4bd8904.tar.gz
scheduling while atomic in cgroup code
mm, memcg: make refill_stock() use get_cpu_light() Nikita reported the following memcg scheduling while atomic bug: Call Trace: [e22d5a90] [c0007ea8] show_stack+0x4c/0x168 (unreliable) [e22d5ad0] [c0618c04] __schedule_bug+0x94/0xb0 [e22d5ae0] [c060b9ec] __schedule+0x530/0x550 [e22d5bf0] [c060bacc] schedule+0x30/0xbc [e22d5c00] [c060ca24] rt_spin_lock_slowlock+0x180/0x27c [e22d5c70] [c00b39dc] res_counter_uncharge_until+0x40/0xc4 [e22d5ca0] [c013ca88] drain_stock.isra.20+0x54/0x98 [e22d5cc0] [c01402ac] __mem_cgroup_try_charge+0x2e8/0xbac [e22d5d70] [c01410d4] mem_cgroup_charge_common+0x3c/0x70 [e22d5d90] [c0117284] __do_fault+0x38c/0x510 [e22d5df0] [c011a5f4] handle_pte_fault+0x98/0x858 [e22d5e50] [c060ed08] do_page_fault+0x42c/0x6fc [e22d5f40] [c000f5b4] handle_page_fault+0xc/0x80 What happens: refill_stock() get_cpu_var() drain_stock() res_counter_uncharge() res_counter_uncharge_until() spin_lock() <== boom Fix it by replacing get/put_cpu_var() with get/put_cpu_light(). Cc: stable-rt@vger.kernel.org Reported-by: Nikita Yushchenko <nyushchenko@dev.rtsoft.ru> Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
-rw-r--r--mm/memcontrol.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index fa54408b66b2..be24d2d186fa 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2512,14 +2512,17 @@ static void __init memcg_stock_init(void)
*/
static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
{
- struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
+ struct memcg_stock_pcp *stock;
+ int cpu = get_cpu_light();
+
+ stock = &per_cpu(memcg_stock, cpu);
if (stock->cached != memcg) { /* reset if necessary */
drain_stock(stock);
stock->cached = memcg;
}
stock->nr_pages += nr_pages;
- put_cpu_var(memcg_stock);
+ put_cpu_light();
}
/*