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| author | KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> | 2012-10-19 17:00:55 +0900 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-10-19 14:32:10 -0700 |
| commit | 9e7814404b77c3e8920bee4277162bf3a7460505 (patch) | |
| tree | f7542b049f29150680507dd211925401beadac9a /fs/proc/internal.h | |
| parent | 3b641bf453497d76ea28c5fc1c666f424ead6dcf (diff) | |
| download | linux-9e7814404b77c3e8920bee4277162bf3a7460505.tar.bz2 | |
hold task->mempolicy while numa_maps scans.
/proc/<pid>/numa_maps scans vma and show mempolicy under
mmap_sem. It sometimes accesses task->mempolicy which can
be freed without mmap_sem and numa_maps can show some
garbage while scanning.
This patch tries to take reference count of task->mempolicy at reading
numa_maps before calling get_vma_policy(). By this, task->mempolicy
will not be freed until numa_maps reaches its end.
V2->v3
- updated comments to be more verbose.
- removed task_lock() in numa_maps code.
V1->V2
- access task->mempolicy only once and remember it. Becase kernel/exit.c
can overwrite it.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/proc/internal.h')
| -rw-r--r-- | fs/proc/internal.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/proc/internal.h b/fs/proc/internal.h index cceaab07ad54..43973b084abf 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -12,6 +12,7 @@ #include <linux/sched.h> #include <linux/proc_fs.h> struct ctl_table_header; +struct mempolicy; extern struct proc_dir_entry proc_root; #ifdef CONFIG_PROC_SYSCTL @@ -74,6 +75,9 @@ struct proc_maps_private { #ifdef CONFIG_MMU struct vm_area_struct *tail_vma; #endif +#ifdef CONFIG_NUMA + struct mempolicy *task_mempolicy; +#endif }; void proc_init_inodecache(void); |