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/openbmc/linux/include/linux/
H A Dhugetlb.h7b24d861 Thu Apr 03 16:47:27 CDT 2014 Davidlohr Bueso <davidlohr@hp.com> 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
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@hp.com: updated changelog]
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Suggested-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7b24d861 Thu Apr 03 16:47:27 CDT 2014 Davidlohr Bueso <davidlohr@hp.com> 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
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@hp.com: updated changelog]
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Suggested-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
/openbmc/linux/mm/
H A Dhugetlb.c7b24d861 Thu Apr 03 16:47:27 CDT 2014 Davidlohr Bueso <davidlohr@hp.com> 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
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@hp.com: updated changelog]
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Suggested-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7b24d861 Thu Apr 03 16:47:27 CDT 2014 Davidlohr Bueso <davidlohr@hp.com> 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
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@hp.com: updated changelog]
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Suggested-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>