[PATCH 3.18 042/150] UBI: Fix invalid vfree()

Greg Kroah-Hartman
2015-01-14T08:43:45Z

From: Richard Weinberger <richard@nod.at>

commit f38aed975c0c3645bbdfc5ebe35726e64caaf588 upstream.

The logic of vfree()'ing vol->upd_buf is tied to vol->updating.
In ubi_start_update() vol->updating is set long before vmalloc()'ing
vol->upd_buf. If we encounter a write failure in ubi_start_update()
before vmalloc() the UBI device release function will try to vfree()
vol->upd_buf because vol->updating is set.
Fix this by allocating vol->upd_buf directly after setting vol->updating.

Fixes:
[ 31.559338] UBI warning: vol_cdev_release: update of volume 2 not finished, volume is damaged
[ 31.559340] ------------[ cut here ]------------
[ 31.559343] WARNING: CPU: 1 PID: 2747 at mm/vmalloc.c:1446 __vunmap+0xe3/0x110()
[ 31.559344] Trying to vfree() nonexistent vm area (ffffc90001f2b000)
[ 31.559345] Modules linked in:
[ 31.565620] 0000000000000bba ffff88002a0cbdb0 ffffffff818f0497 ffff88003b9ba148
[ 31.566347] ffff88002a0cbde0 ffffffff8156f515 ffff88003b9ba148 0000000000000bba
[ 31.567073] 0000000000000000 0000000000000000 ffff88002a0cbe88 ffffffff8156c10a
[ 31.567793] Call Trace:
[ 31.568034] [<ffffffff818f0497>] dump_stack+0x4e/0x7a
[ 31.568510] [<ffffffff8156f515>] ubi_io_write_vid_hdr+0x155/0x160
[ 31.569084] [<ffffffff8156c10a>] ubi_eba_write_leb+0x23a/0x870
[ 31.569628] [<ffffffff81569b36>] vol_cdev_write+0x226/0x380
[ 31.570155] [<ffffffff81179265>] vfs_write+0xb5/0x1f0
[ 31.570627] [<ffffffff81179f8a>] SyS_pwrite64+0x6a/0xa0
[ 31.571123] [<ffffffff818fde12>] system_call_fastpath+0x16/0x1b

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/mtd/ubi/upd.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

--- a/drivers/mtd/ubi/upd.c
+++ b/drivers/mtd/ubi/upd.c
@@ -133,6 +133,10 @@ int ubi_start_update(struct ubi_device *
ubi_assert(!vol->updating && !vol->changing_leb);
vol->updating = 1;

+ vol->upd_buf = vmalloc(ubi->leb_size);
+ if (!vol->upd_buf)
+ return -ENOMEM;
+
err = set_update_marker(ubi, vol);
if (err)
return err;
@@ -152,14 +156,12 @@ int ubi_start_update(struct ubi_device *
err = clear_update_marker(ubi, vol, 0);
if (err)
return err;
+
+ vfree(vol->upd_buf);
vol->updating = 0;
return 0;
}

- vol->upd_buf = vmalloc(ubi->leb_size);
- if (!vol->upd_buf)
- return -ENOMEM;
-
vol->upd_ebs = div_u64(bytes + vol->usable_leb_size - 1,
vol->usable_leb_size);
vol->upd_bytes = bytes;