diff options
| author | Xiaomeng Tong <xiam0nd.tong@gmail.com> | 2022-04-08 16:47:15 +0800 |
|---|---|---|
| committer | Song Liu <song@kernel.org> | 2022-04-25 14:00:35 -0700 |
| commit | 64c54d9244a4efe9bc6e9c98e13c4bbb8bb39083 (patch) | |
| tree | e7460c9fd8dd10b4556fe3728a7490eeba0398e5 /drivers/md | |
| parent | fc8738343eefc4ea8afb6122826dea48eacde514 (diff) | |
| download | linux-64c54d9244a4efe9bc6e9c98e13c4bbb8bb39083.tar.bz2 | |
md: fix an incorrect NULL check in md_reload_sb
The bug is here:
if (!rdev || rdev->desc_nr != nr) {
The list iterator value 'rdev' will *always* be set and non-NULL
by rdev_for_each_rcu(), so it is incorrect to assume that the
iterator value will be NULL if the list is empty or no element
found (In fact, it will be a bogus pointer to an invalid struct
object containing the HEAD). Otherwise it will bypass the check
and lead to invalid memory access passing the check.
To fix the bug, use a new variable 'iter' as the list iterator,
while using the original variable 'pdev' as a dedicated pointer to
point to the found element.
Cc: stable@vger.kernel.org
Fixes: 70bcecdb1534 ("md-cluster: Improve md_reload_sb to be less error prone")
Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
Signed-off-by: Song Liu <song@kernel.org>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/md.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index f07f007ecae4..4e3c314b3862 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -9795,16 +9795,18 @@ static int read_rdev(struct mddev *mddev, struct md_rdev *rdev) void md_reload_sb(struct mddev *mddev, int nr) { - struct md_rdev *rdev; + struct md_rdev *rdev = NULL, *iter; int err; /* Find the rdev */ - rdev_for_each_rcu(rdev, mddev) { - if (rdev->desc_nr == nr) + rdev_for_each_rcu(iter, mddev) { + if (iter->desc_nr == nr) { + rdev = iter; break; + } } - if (!rdev || rdev->desc_nr != nr) { + if (!rdev) { pr_warn("%s: %d Could not find rdev with nr %d\n", __func__, __LINE__, nr); return; } |