Subject: [obsolete] mm-hugetlb-fix-race-in-region-tracking-update.patch removed from -mm tree
To: iamjoonsoo.kim@xxxxxxx,david@xxxxxxxxxxxxxxxxxxxxx,davidlohr@xxxxxx,n-horiguchi@xxxxxxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Mon, 03 Feb 2014 16:36:24 -0800
The patch titled
Subject: mm, hugetlb: fix race in region tracking
has been removed from the -mm tree. Its filename was
mm-hugetlb-fix-race-in-region-tracking-update.patch
This patch was dropped because it is obsolete
------------------------------------------------------
From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Subject: mm, hugetlb: fix race in region tracking
There is a race condition if we map a same file on different processes.
Region tracking is protected by mmap_sem and hugetlb_instantiation_mutex.
When we do mmap, we don't grab a hugetlb_instantiation_mutex, but only
the, mmap_sem (exclusively). This doesn't prevent other tasks from
modifying the region structure, so it can be modified by two processes
concurrently.
To solve this, introduce a spinlock to resv_map and make region manipulation
function grab it before they do actual work.
[davidlohr@xxxxxx: updated changelog]
Signed-off-by: Davidlohr Bueso <davidlohr@xxxxxx>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Suggested-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Acked-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
Cc: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 18 ++++++++----------
1 file changed, 8 insertions(+), 10 deletions(-)
diff -puN mm/hugetlb.c~mm-hugetlb-fix-race-in-region-tracking-update mm/hugetlb.c
--- a/mm/hugetlb.c~mm-hugetlb-fix-race-in-region-tracking-update
+++ a/mm/hugetlb.c
@@ -206,15 +206,17 @@ retry:
if (!nrg)
return -ENOMEM;
- nrg->from = f;
- nrg->to = f;
- INIT_LIST_HEAD(&nrg->link);
goto retry;
}
+ nrg->from = f;
+ nrg->to = f;
+ INIT_LIST_HEAD(&nrg->link);
list_add(&nrg->link, rg->link.prev);
+ nrg = NULL;
+
chg = t - f;
- goto out_nrg;
+ goto out_locked;
}
/* Round our left edge to the current segment if it encloses us. */
@@ -227,7 +229,7 @@ retry:
if (&rg->link == head)
break;
if (rg->from > t)
- goto out;
+ goto out_locked;
/* We overlap with this area, if it extends further than
* us then we must extend ourselves. Account for its
@@ -239,14 +241,10 @@ retry:
chg -= rg->to - rg->from;
}
-out:
+out_locked:
spin_unlock(&resv->lock);
- /* We already know we raced and no longer need the new region */
kfree(nrg);
return chg;
-out_nrg:
- spin_unlock(&resv->lock);
- return chg;
}
static long region_truncate(struct resv_map *resv, long end)
_
Patches currently in -mm which might be from iamjoonsoo.kim@xxxxxxx are
kthread-ensure-locality-of-task_struct-allocations.patch
mm-hugetlb-unify-region-structure-handling.patch
mm-hugetlb-improve-cleanup-resv_map-parameters.patch
mm-hugetlb-fix-race-in-region-tracking.patch
mm-hugetlb-remove-resv_map_put.patch
mm-hugetlb-use-vma_resv_map-map-types.patch
mm-hugetlb-use-vma_resv_map-map-types-update.patch
mm-hugetlb-use-vma_resv_map-map-types-update-fix.patch
mm-hugetlb-improve-page-fault-scalability.patch
mm-hugetlb-improve-page-fault-scalability-fix.patch
mm-hugetlb-improve-page-fault-scalability-update.patch
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