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 |
|---|---|---|
| auth_gss | ||
| xprtrdma | ||
| Kconfig | -rw-r--r-- | 1004 bytes |
| Makefile | -rw-r--r-- | 541 bytes |
| addr.c | -rw-r--r-- | 8.7 KB |
| auth.c | -rw-r--r-- | 15.4 KB |
| auth_generic.c | -rw-r--r-- | 4.5 KB |
| auth_null.c | -rw-r--r-- | 2.5 KB |
| auth_unix.c | -rw-r--r-- | 5.5 KB |
| backchannel_rqst.c | -rw-r--r-- | 8.8 KB |
| bc_svc.c | -rw-r--r-- | 2.0 KB |
| cache.c | -rw-r--r-- | 42.3 KB |
| clnt.c | -rw-r--r-- | 44.2 KB |
| netns.h | -rw-r--r-- | 353 bytes |
| rpc_pipe.c | -rw-r--r-- | 24.7 KB |
| rpcb_clnt.c | -rw-r--r-- | 26.5 KB |
| sched.c | -rw-r--r-- | 24.0 KB |
| socklib.c | -rw-r--r-- | 4.5 KB |
| stats.c | -rw-r--r-- | 6.8 KB |
| sunrpc.h | -rw-r--r-- | 1.7 KB |
| sunrpc_syms.c | -rw-r--r-- | 2.2 KB |
| svc.c | -rw-r--r-- | 30.7 KB |
| svc_xprt.c | -rw-r--r-- | 33.1 KB |
| svcauth.c | -rw-r--r-- | 3.8 KB |
| svcauth_unix.c | -rw-r--r-- | 22.1 KB |
| svcsock.c | -rw-r--r-- | 40.0 KB |
| sysctl.c | -rw-r--r-- | 3.5 KB |
| timer.c | -rw-r--r-- | 2.9 KB |
| xdr.c | -rw-r--r-- | 28.2 KB |
| xprt.c | -rw-r--r-- | 31.0 KB |
| xprtsock.c | -rw-r--r-- | 65.4 KB |
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