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author | Mike Galbraith <umgwanakikbuti@gmail.com> | 2014-06-21 10:09:48 +0200 |
---|---|---|
committer | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2016-02-13 00:36:36 +0100 |
commit | 9438524b156388f4483c909540f9cfe0bd89933e (patch) | |
tree | fd76d8e8a7ed095b36d96ecd1bdafcdb534b0253 | |
parent | e7a5103855a58cb0c767416b2e2ad3044ce59826 (diff) | |
download | rt-linux-9438524b156388f4483c909540f9cfe0bd89933e.tar.gz |
memcontrol: Prevent 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().
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>
-rw-r--r-- | mm/memcontrol.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 909f339cad7436..4a8fac17dbd7fe 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1937,14 +1937,17 @@ static void drain_local_stock(struct work_struct *dummy) */ 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(); } /* |