From 84e7c6786aad1dffa04f5729270f8fcd7281fe4b Mon Sep 17 00:00:00 2001 From: Mark-PK Tsai Date: Wed, 16 Mar 2022 15:43:28 +0800 Subject: [PATCH] driver core: Prevent overriding async driver of a device before it probe When there are 2 matched drivers for a device using async probe mechanism, the dev->p->async_driver might be overridden by the last attached driver. So just skip the later one if the previous matched driver was not handled by async thread yet. Below is my use case which having this problem. Make both driver mmcblk and mmc_test allow async probe, the dev->p->async_driver will be overridden by the later driver mmc_test and bind to the device then claim it for testing. When it happen, mmcblk will never do probe again. Signed-off-by: Mark-PK Tsai Link: https://lore.kernel.org/r/20220316074328.1801-1-mark-pk.tsai@mediatek.com Signed-off-by: Greg Kroah-Hartman --- drivers/base/dd.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 923dbc2927b5d..152d3e6bfc067 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -1081,6 +1081,7 @@ static void __driver_attach_async_helper(void *_dev, async_cookie_t cookie) __device_driver_lock(dev, dev->parent); drv = dev->p->async_driver; + dev->p->async_driver = NULL; ret = driver_probe_device(drv, dev); __device_driver_unlock(dev, dev->parent); @@ -1127,7 +1128,7 @@ static int __driver_attach(struct device *dev, void *data) */ dev_dbg(dev, "probing driver %s asynchronously\n", drv->name); device_lock(dev); - if (!dev->driver) { + if (!dev->driver && !dev->p->async_driver) { get_device(dev); dev->p->async_driver = drv; async_schedule_dev(__driver_attach_async_helper, dev); -- 2.30.2