Commit 92a3d03a authored Dec 22, 2006 by Badari Pulavarty Committed by Linus Torvalds Dec 22, 2006

[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>

parent ba008404

mm/shmem.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -515,7 +515,12 @@ static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end)
		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);