From e9506871a8ea304cde48ff4a57226df2aadddae3 Mon Sep 17 00:00:00 2001 From: Danilo Krummrich Date: Sat, 18 Apr 2026 18:22:18 +0200 Subject: driver core: use READ_ONCE() for dev->driver in dev_has_sync_state() dev_has_sync_state() reads dev->driver twice without holding device_lock() -- once for the NULL check and once to dereference ->sync_state. Some callers only hold device_links_write_lock, which doesn't prevent a concurrent unbind from clearing dev->driver via device_unbind_cleanup(). Fix it by reading dev->driver exactly once with READ_ONCE(), pairing with the WRITE_ONCE() in device_set_driver(). Link: https://lore.kernel.org/driver-core/DHW8QPU1VU1F.3P6PH69HLFBYC@kernel.org/ Fixes: ac338acf514e ("driver core: Add dev_has_sync_state()") Reviewed-by: Rafael J. Wysocki (Intel) Acked-by: Greg Kroah-Hartman Reviewed-by: Saravana Kannan Link: https://patch.msgid.link/20260418162221.1121873-1-dakr@kernel.org Signed-off-by: Danilo Krummrich --- include/linux/device.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/device.h b/include/linux/device.h index 3bf86d2f9544..56a96e41d2c9 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -1063,9 +1063,12 @@ static inline void device_lock_assert(struct device *dev) static inline bool dev_has_sync_state(struct device *dev) { + struct device_driver *drv; + if (!dev) return false; - if (dev->driver && dev->driver->sync_state) + drv = READ_ONCE(dev->driver); + if (drv && drv->sync_state) return true; if (dev->bus && dev->bus->sync_state) return true; -- cgit v1.2.3