From d59f21bebe9d0fda34027ff1afda4f2b0d5f1869 Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Thu, 2 Oct 2014 15:00:35 +0200 Subject: UBI: Fastmap: Fix races in ubi_wl_get_peb() ubi_wl_get_peb() has two problems, it reads the pool size and usage counters without any protection. While reading one value would be perfectly fine it reads multiple values and compares them. This is racy and can lead to incorrect pool handling. Furthermore ubi_update_fastmap() is called without wl_lock held, before incrementing the used counter it needs to be checked again. It could happen that another thread consumed all PEBs from the pool and the counter goes beyond ->size. Signed-off-by: Richard Weinberger --- drivers/mtd/ubi/ubi.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/mtd/ubi/ubi.h') diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h index 7a33470c0416..bc13d14e02c4 100644 --- a/drivers/mtd/ubi/ubi.h +++ b/drivers/mtd/ubi/ubi.h @@ -443,7 +443,8 @@ struct ubi_debug_info { * @pq_head: protection queue head * @wl_lock: protects the @used, @free, @pq, @pq_head, @lookuptbl, @move_from, * @move_to, @move_to_put @erase_pending, @wl_scheduled, @works, - * @erroneous, @erroneous_peb_count, and @fm_work_scheduled fields + * @erroneous, @erroneous_peb_count, @fm_work_scheduled, @fm_pool, + * and @fm_wl_pool fields * @move_mutex: serializes eraseblock moves * @work_sem: used to wait for all the scheduled works to finish and prevent * new works from being submitted -- cgit v1.2.3-59-g8ed1b