From: Miklos Szeredi Date: Thu, 24 Feb 2011 14:49:53 +0000 (+0100) Subject: mm: fix refcounting in swapon X-Git-Tag: firefly_0821_release~7613^2~2374 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=8074b26f67165bf045d92e778c9c10dc5e207fc6;p=firefly-linux-kernel-4.4.55.git mm: fix refcounting in swapon Grab a reference to bdev before calling blkdev_get(), which expects the refcount to be already incremented and either returns success or decrements the refcount and returns an error. The bug was introduced by e525fd89 (block: make blkdev_get/put() handle exclusive access), which didn't take into account this behavior of blkdev_get(). Acked-by: Tejun Heo Signed-off-by: Miklos Szeredi Signed-off-by: Linus Torvalds --- diff --git a/mm/swapfile.c b/mm/swapfile.c index 07a458d72fa8..0341c5700e34 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1940,7 +1940,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) error = -EINVAL; if (S_ISBLK(inode->i_mode)) { - bdev = I_BDEV(inode); + bdev = bdgrab(I_BDEV(inode)); error = blkdev_get(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL, sys_swapon); if (error < 0) {