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author | James Morris <jmorris@namei.org> | 2011-01-10 09:46:24 +1100 |
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committer | James Morris <jmorris@namei.org> | 2011-01-10 09:46:24 +1100 |
commit | d2e7ad19229f982fc1eb731827d82ceac90abfb3 (patch) | |
tree | 98a3741b4d4b27a48b3c7ea9babe331e539416a8 /mm/memcontrol.c | |
parent | d03a5d888fb688c832d470b749acc5ed38e0bc1d (diff) | |
parent | 0c21e3aaf6ae85bee804a325aa29c325209180fd (diff) | |
download | linux-d2e7ad19229f982fc1eb731827d82ceac90abfb3.tar.bz2 |
Merge branch 'master' into next
Conflicts:
security/smack/smack_lsm.c
Verified and added fix by Stephen Rothwell <sfr@canb.auug.org.au>
Ok'd by Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r-- | mm/memcontrol.c | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 7a22b4129211..00bb8a64d028 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1925,19 +1925,18 @@ again: rcu_read_lock(); p = rcu_dereference(mm->owner); - VM_BUG_ON(!p); /* - * because we don't have task_lock(), "p" can exit while - * we're here. In that case, "mem" can point to root - * cgroup but never be NULL. (and task_struct itself is freed - * by RCU, cgroup itself is RCU safe.) Then, we have small - * risk here to get wrong cgroup. But such kind of mis-account - * by race always happens because we don't have cgroup_mutex(). - * It's overkill and we allow that small race, here. + * Because we don't have task_lock(), "p" can exit. + * In that case, "mem" can point to root or p can be NULL with + * race with swapoff. Then, we have small risk of mis-accouning. + * But such kind of mis-account by race always happens because + * we don't have cgroup_mutex(). It's overkill and we allo that + * small race, here. + * (*) swapoff at el will charge against mm-struct not against + * task-struct. So, mm->owner can be NULL. */ mem = mem_cgroup_from_task(p); - VM_BUG_ON(!mem); - if (mem_cgroup_is_root(mem)) { + if (!mem || mem_cgroup_is_root(mem)) { rcu_read_unlock(); goto done; } |