diff options
| author | Hans de Goede <hansg@kernel.org> | 2025-07-19 20:01:04 +0200 |
|---|---|---|
| committer | Wolfram Sang <wsa+renesas@sang-engineering.com> | 2025-07-28 10:41:36 +0200 |
| commit | 1c24e5fc0c7096e00c202a6a3e0c342c1afb47c2 (patch) | |
| tree | 8cafde9f7e7af7a5f3a7dc47649c4a83da81d508 | |
| parent | f61389a9cd26b424485acade726ccfff96c749de (diff) | |
i2c: core: Fix double-free of fwnode in i2c_unregister_device()
Before commit df6d7277e552 ("i2c: core: Do not dereference fwnode in struct
device"), i2c_unregister_device() only called fwnode_handle_put() on
of_node-s in the form of calling of_node_put(client->dev.of_node).
But after this commit the i2c_client's fwnode now unconditionally gets
fwnode_handle_put() on it.
When the i2c_client has no primary (ACPI / OF) fwnode but it does have
a software fwnode, the software-node will be the primary node and
fwnode_handle_put() will put() it.
But for the software fwnode device_remove_software_node() will also put()
it leading to a double free:
[ 82.665598] ------------[ cut here ]------------
[ 82.665609] refcount_t: underflow; use-after-free.
[ 82.665808] WARNING: CPU: 3 PID: 1502 at lib/refcount.c:28 refcount_warn_saturate+0xba/0x11
...
[ 82.666830] RIP: 0010:refcount_warn_saturate+0xba/0x110
...
[ 82.666962] <TASK>
[ 82.666971] i2c_unregister_device+0x60/0x90
Fix this by not calling fwnode_handle_put() when the primary fwnode is
a software-node.
Fixes: df6d7277e552 ("i2c: core: Do not dereference fwnode in struct device")
Cc: stable@vger.kernel.org
Signed-off-by: Hans de Goede <hansg@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
| -rw-r--r-- | drivers/i2c/i2c-core-base.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 2ad2b1838f0f..0849aa44952d 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -1066,7 +1066,13 @@ void i2c_unregister_device(struct i2c_client *client) of_node_clear_flag(to_of_node(fwnode), OF_POPULATED); else if (is_acpi_device_node(fwnode)) acpi_device_clear_enumerated(to_acpi_device_node(fwnode)); - fwnode_handle_put(fwnode); + + /* + * If the primary fwnode is a software node it is free-ed by + * device_remove_software_node() below, avoid double-free. + */ + if (!is_software_node(fwnode)) + fwnode_handle_put(fwnode); device_remove_software_node(&client->dev); device_unregister(&client->dev); |