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authorKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>2012-10-19 12:00:55 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-20 01:32:10 +0400
commit9e7814404b77c3e8920bee4277162bf3a7460505 (patch)
treef7542b049f29150680507dd211925401beadac9a /fs/proc/internal.h
parent3b641bf453497d76ea28c5fc1c666f424ead6dcf (diff)
downloadlinux-9e7814404b77c3e8920bee4277162bf3a7460505.tar.xz
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.h4
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);