[4.9,50/78] iomap: fix integer truncation issues in the zeroing and dirtying helpers

Commit Message

Greg KH Sept. 18, 2017, 9:11 a.m. UTC

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Christoph Hellwig <[e-mail]>

commit e28ae8e428fefe2facd72cea9f29906ecb9c861d upstream.

Fix the min_t calls in the zeroing and dirtying helpers to perform the
comparisms on 64-bit types, which prevents them from incorrectly
being truncated, and larger zeroing operations being stuck in a never
ending loop.

Special thanks to Markus Stockhausen for spotting the bug.

Reported-by: Paul Menzel <[e-mail]>
Tested-by: Paul Menzel <[e-mail]>
Signed-off-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Darrick J. Wong <[e-mail]>
Signed-off-by: Darrick J. Wong <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>
---
 fs/iomap.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)



--
To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
the body of a message to [e-mail]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch

--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -281,7 +281,7 @@  iomap_dirty_actor(struct inode *inode, l
 		unsigned long bytes;	/* Bytes to write to page */
 
 		offset = (pos & (PAGE_SIZE - 1));
-		bytes = min_t(unsigned long, PAGE_SIZE - offset, length);
+		bytes = min_t(loff_t, PAGE_SIZE - offset, length);
 
 		rpage = __iomap_read_page(inode, pos);
 		if (IS_ERR(rpage))
@@ -376,7 +376,7 @@  iomap_zero_range_actor(struct inode *ino
 		unsigned offset, bytes;
 
 		offset = pos & (PAGE_SIZE - 1); /* Within page */
-		bytes = min_t(unsigned, PAGE_SIZE - offset, count);
+		bytes = min_t(loff_t, PAGE_SIZE - offset, count);
 
 		if (IS_DAX(inode))
 			status = iomap_dax_zero(pos, offset, bytes, iomap);