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| author | Xiaomeng Tong <xiam0nd.tong@gmail.com> | 2022-04-08 11:47:15 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-06-09 11:21:25 +0300 |
| commit | b2b01444228d59ba62b75286c84cea40bb064c64 (patch) | |
| tree | 27a63db0972bff14655f47ed44685dbda0a044bf /drivers/md | |
| parent | 2401f1cf3dee6974d799a4387f0c5d98cec29326 (diff) | |
| download | linux-b2b01444228d59ba62b75286c84cea40bb064c64.tar.xz | |
md: fix an incorrect NULL check in md_reload_sb
commit 64c54d9244a4efe9bc6e9c98e13c4bbb8bb39083 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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 e0f99c8750dc..7a9701adee73 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -9730,16 +9730,18 @@ 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; } |