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>
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crush | ||
Kconfig | -rw-r--r-- | 753 bytes |
Makefile | -rw-r--r-- | 766 bytes |
armor.c | -rw-r--r-- | 1.9 KB |
auth.c | -rw-r--r-- | 5.6 KB |
auth_none.c | -rw-r--r-- | 2.9 KB |
auth_none.h | -rw-r--r-- | 536 bytes |
auth_x.c | -rw-r--r-- | 16.2 KB |
auth_x.h | -rw-r--r-- | 847 bytes |
auth_x_protocol.h | -rw-r--r-- | 1.7 KB |
buffer.c | -rw-r--r-- | 1.4 KB |
ceph_common.c | -rw-r--r-- | 11.9 KB |
ceph_fs.c | -rw-r--r-- | 1.7 KB |
ceph_hash.c | -rw-r--r-- | 2.7 KB |
ceph_strings.c | -rw-r--r-- | 2.5 KB |
crypto.c | -rw-r--r-- | 10.2 KB |
crypto.h | -rw-r--r-- | 1.3 KB |
debugfs.c | -rw-r--r-- | 6.5 KB |
messenger.c | -rw-r--r-- | 60.7 KB |
mon_client.c | -rw-r--r-- | 24.4 KB |
msgpool.c | -rw-r--r-- | 1.5 KB |
osd_client.c | -rw-r--r-- | 44.9 KB |
osdmap.c | -rw-r--r-- | 26.6 KB |
pagelist.c | -rw-r--r-- | 3.6 KB |
pagevec.c | -rw-r--r-- | 4.5 KB |
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