Messages in this thread Patch in this message | | | Date | Tue, 23 Jun 2015 18:54:45 +0800 | From | Wang YanQing <> | Subject | [PATCH] fs:super:get_anon_bdev: fix race condition could cause dev exceed its upper limitation |
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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 <udknight@gmail.com> --- fs/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/super.c b/fs/super.c index 928c20f..b613723 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) -- 1.8.5.6.2.g3d8a54e.dirty
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