[[PATCH RT 26/39] scheduling while atomic in cgroup code] On 12/03/2015 (Thu 15:13) Steven Rostedt wrote: > 3.14.34-rt32-rc1 stable review patch. > If anyone has any objections, please let me know. > > ------------------ > > From: Mike Galbraith <umgwanakikbuti@xxxxxxxxx> > > mm, memcg: make refill_stock() use get_cpu_light() This looks like only 1/2 of Mike's original patch: https://lkml.org/lkml/2014/6/21/11 I suspect that is because 3.18 could only use 1/2 of it, and based on the SOB lines, this is backported from 3.18. The other half applies to 3.14 -- testing in progress; not sure about the 3.10-rt and earlier.... P. -- > > 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@xxxxxxxxxxxxxxx > Reported-by: Nikita Yushchenko <nyushchenko@xxxxxxxxxxxxx> > Signed-off-by: Mike Galbraith <umgwanakikbuti@xxxxxxxxx> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> > Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx> > --- > mm/memcontrol.c | 7 +++++-- > 1 file 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(); > } > > /* > -- > 2.1.4 > > -- To unsubscribe from this list: send the line "unsubscribe stable-rt" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
