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| author |   Vladimir Oltean <vladimir.oltean@nxp.com> | 2021-08-17 17:52:45 +0300 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2021-08-18 10:21:01 +0100 |
| commit | ed5d2937a6a8f12e7f815748f991990e79ac4cd1 (patch) | |
| tree | a921caa781a1eb0288b07f0861d3f8052646ed6e /drivers/net/dsa/sja1105/sja1105_mdio.c | |
| parent | sch_cake: fix srchost/dsthost hashing mode (diff) | |
| download | linux-dev-ed5d2937a6a8f12e7f815748f991990e79ac4cd1.tar.xz linux-dev-ed5d2937a6a8f12e7f815748f991990e79ac4cd1.zip | |
net: dsa: sja1105: fix use-after-free after calling of_find_compatible_node, or worse
It seems that of_find_compatible_node has a weird calling convention in
which it calls of_node_put() on the "from" node argument, instead of
leaving that up to the caller. This comes from the fact that
of_find_compatible_node with a non-NULL "from" argument it only supposed
to be used as the iterator function of for_each_compatible_node(). OF
iterator functions call of_node_get on the next OF node and of_node_put()
on the previous one.
When of_find_compatible_node calls of_node_put, it actually never
expects the refcount to drop to zero, because the call is done under the
atomic devtree_lock context, and when the refcount drops to zero it
triggers a kobject and a sysfs file deletion, which assume blocking
context.
So any driver call to of_find_compatible_node is probably buggy because
an unexpected of_node_put() takes place.
What should be done is to use the of_get_compatible_child() function.
Fixes: 5a8f09748ee7 ("net: dsa: sja1105: register the MDIO buses for 100base-T1 and 100base-TX")
Link: https://lore.kernel.org/netdev/20210814010139.kzryimmp4rizlznt@skbuf/
Suggested-by: Frank Rowand <frowand.list@gmail.com>
Suggested-by: Rob Herring <robh+dt@kernel.org>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/dsa/sja1105/sja1105_mdio.c')
| -rw-r--r-- | drivers/net/dsa/sja1105/sja1105_mdio.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/drivers/net/dsa/sja1105/sja1105_mdio.c b/drivers/net/dsa/sja1105/sja1105_mdio.c index 19aea8fb76f6..705d3900e43a 100644 --- a/drivers/net/dsa/sja1105/sja1105_mdio.c +++ b/drivers/net/dsa/sja1105/sja1105_mdio.c @@ -284,8 +284,7 @@ static int sja1105_mdiobus_base_tx_register(struct sja1105_private *priv, struct mii_bus *bus; int rc = 0; - np = of_find_compatible_node(mdio_node, NULL, - "nxp,sja1110-base-tx-mdio"); + np = of_get_compatible_child(mdio_node, "nxp,sja1110-base-tx-mdio"); if (!np) return 0; @@ -339,8 +338,7 @@ static int sja1105_mdiobus_base_t1_register(struct sja1105_private *priv, struct mii_bus *bus; int rc = 0; - np = of_find_compatible_node(mdio_node, NULL, - "nxp,sja1110-base-t1-mdio"); + np = of_get_compatible_child(mdio_node, "nxp,sja1110-base-t1-mdio"); if (!np) return 0; |