[PATCH] Fix for shmem_truncate_range() BUG_ON()
Ran into BUG() while doing madvise(REMOVE) testing. If we are punching a
hole into shared memory segment using madvise(REMOVE) and the entire hole
is below the indirect blocks, we hit following assert.
BUG_ON(limit <= SHMEM_NR_DIRECT);
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/shmem.c b/mm/shmem.c
index 4bb28d2..70da7a0 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -515,7 +515,12 @@
size = SHMEM_NR_DIRECT;
nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size);
}
- if (!topdir)
+
+ /*
+ * If there are no indirect blocks or we are punching a hole
+ * below indirect blocks, nothing to be done.
+ */
+ if (!topdir || (punch_hole && (limit <= SHMEM_NR_DIRECT)))
goto done2;
BUG_ON(limit <= SHMEM_NR_DIRECT);