From 1af95de6f0119d5bde02d3a811a9f3a3661e954e Mon Sep 17 00:00:00 2001 From: Wang YanQing Date: Tue, 23 Jun 2015 18:54:45 +0800 Subject: [PATCH] fs:super:get_anon_bdev: fix race condition could cause dev exceed its upper limitation Execution of get_anon_bdev concurrently and preemptive kernel all could bring race condition, it isn't enough to check dev against its upper limitation with equality operator only. This patch fix it. Signed-off-by: Wang YanQing Signed-off-by: Al Viro --- fs/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/super.c b/fs/super.c index 928c20f47af9..b61372354f2b 100644 --- a/fs/super.c +++ b/fs/super.c @@ -842,7 +842,7 @@ int get_anon_bdev(dev_t *p) else if (error) return -EAGAIN; - if (dev == (1 << MINORBITS)) { + if (dev >= (1 << MINORBITS)) { spin_lock(&unnamed_dev_lock); ida_remove(&unnamed_dev_ida, dev); if (unnamed_dev_start > dev)