Revision b1dd693e5b9348bd68a80e679e03cf9c0973b01b authored by Daisuke Nishimura on 24 November 2010, 20:57:06 UTC, committed by Linus Torvalds on 24 November 2010, 21:50:44 UTC
__mem_cgroup_try_charge() can be called under down_write(&mmap_sem)(e.g.
mlock does it). This means it can cause deadlock if it races with move charge:
Ex.1)
move charge | try charge
--------------------------------------+------------------------------
mem_cgroup_can_attach() | down_write(&mmap_sem)
mc.moving_task = current | ..
mem_cgroup_precharge_mc() | __mem_cgroup_try_charge()
mem_cgroup_count_precharge() | prepare_to_wait()
down_read(&mmap_sem) | if (mc.moving_task)
-> cannot aquire the lock | -> true
| schedule()
Ex.2)
move charge | try charge
--------------------------------------+------------------------------
mem_cgroup_can_attach() |
mc.moving_task = current |
mem_cgroup_precharge_mc() |
mem_cgroup_count_precharge() |
down_read(&mmap_sem) |
.. |
up_read(&mmap_sem) |
| down_write(&mmap_sem)
mem_cgroup_move_task() | ..
mem_cgroup_move_charge() | __mem_cgroup_try_charge()
down_read(&mmap_sem) | prepare_to_wait()
-> cannot aquire the lock | if (mc.moving_task)
| -> true
| schedule()
To avoid this deadlock, we do all the move charge works (both can_attach() and
attach()) under one mmap_sem section.
And after this patch, we set/clear mc.moving_task outside mc.lock, because we
use the lock only to check mc.from/to.
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 11e7946
| File | Mode | Size |
|---|---|---|
| Kconfig | -rw-r--r-- | 16.8 KB |
| Makefile | -rw-r--r-- | 1.8 KB |
| act_api.c | -rw-r--r-- | 23.5 KB |
| act_csum.c | -rw-r--r-- | 13.2 KB |
| act_gact.c | -rw-r--r-- | 5.4 KB |
| act_ipt.c | -rw-r--r-- | 7.4 KB |
| act_mirred.c | -rw-r--r-- | 6.8 KB |
| act_nat.c | -rw-r--r-- | 7.3 KB |
| act_pedit.c | -rw-r--r-- | 6.2 KB |
| act_police.c | -rw-r--r-- | 9.9 KB |
| act_simple.c | -rw-r--r-- | 5.2 KB |
| act_skbedit.c | -rw-r--r-- | 5.7 KB |
| cls_api.c | -rw-r--r-- | 13.7 KB |
| cls_basic.c | -rw-r--r-- | 6.5 KB |
| cls_cgroup.c | -rw-r--r-- | 7.2 KB |
| cls_flow.c | -rw-r--r-- | 16.3 KB |
| cls_fw.c | -rw-r--r-- | 8.3 KB |
| cls_route.c | -rw-r--r-- | 12.2 KB |
| cls_rsvp.c | -rw-r--r-- | 761 bytes |
| cls_rsvp.h | -rw-r--r-- | 14.7 KB |
| cls_rsvp6.c | -rw-r--r-- | 768 bytes |
| cls_tcindex.c | -rw-r--r-- | 11.7 KB |
| cls_u32.c | -rw-r--r-- | 16.6 KB |
| em_cmp.c | -rw-r--r-- | 2.1 KB |
| em_meta.c | -rw-r--r-- | 21.4 KB |
| em_nbyte.c | -rw-r--r-- | 1.9 KB |
| em_text.c | -rw-r--r-- | 3.7 KB |
| em_u32.c | -rw-r--r-- | 1.4 KB |
| ematch.c | -rw-r--r-- | 14.5 KB |
| sch_api.c | -rw-r--r-- | 40.7 KB |
| sch_atm.c | -rw-r--r-- | 19.0 KB |
| sch_blackhole.c | -rw-r--r-- | 1.2 KB |
| sch_cbq.c | -rw-r--r-- | 47.5 KB |
| sch_drr.c | -rw-r--r-- | 11.4 KB |
| sch_dsmark.c | -rw-r--r-- | 11.2 KB |
| sch_fifo.c | -rw-r--r-- | 4.3 KB |
| sch_generic.c | -rw-r--r-- | 20.7 KB |
| sch_gred.c | -rw-r--r-- | 13.3 KB |
| sch_hfsc.c | -rw-r--r-- | 40.6 KB |
| sch_htb.c | -rw-r--r-- | 41.9 KB |
| sch_ingress.c | -rw-r--r-- | 3.2 KB |
| sch_mq.c | -rw-r--r-- | 5.6 KB |
| sch_multiq.c | -rw-r--r-- | 9.3 KB |
| sch_netem.c | -rw-r--r-- | 15.3 KB |
| sch_prio.c | -rw-r--r-- | 8.3 KB |
| sch_red.c | -rw-r--r-- | 7.9 KB |
| sch_sfq.c | -rw-r--r-- | 14.0 KB |
| sch_tbf.c | -rw-r--r-- | 10.4 KB |
| sch_teql.c | -rw-r--r-- | 12.0 KB |
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