devcoredump: Send uevent once devcd is ready

[ Upstream commit af54d778a03853801d681c98c0c2a6c316ef9ca7 ]

dev_coredumpm() creates a devcoredump device and adds it
to the core kernel framework which eventually end up
sending uevent to the user space and later creates a
symbolic link to the failed device. An application
running in userspace may be interested in this symbolic
link to get the name of the failed device.

In a issue scenario, once uevent sent to the user space
it start reading '/sys/class/devcoredump/devcdX/failing_device'
to get the actual name of the device which might not been
created and it is in its path of creation.

To fix this, suppress sending uevent till the failing device
symbolic link gets created and send uevent once symbolic
link is created successfully.

Fixes: 833c95456a70 ("device coredump: add new device coredump class")
Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/1700232572-25823-1-git-send-email-quic_mojha@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/base/devcoredump.c b/drivers/base/devcoredump.c
index 1ba4af7f2f21..b13574cdef69 100644
--- a/drivers/base/devcoredump.c
+++ b/drivers/base/devcoredump.c
@@ -376,6 +376,7 @@ void dev_coredumpm(struct device *dev, struct module *owner,
 	devcd->devcd_dev.class = &devcd_class;
 
 	mutex_lock(&devcd->mutex);
+	dev_set_uevent_suppress(&devcd->devcd_dev, true);
 	if (device_add(&devcd->devcd_dev))
 		goto put_device;
 
@@ -387,6 +388,8 @@ void dev_coredumpm(struct device *dev, struct module *owner,
 			      "devcoredump"))
 		/* nothing - symlink will be missing */;
 
+	dev_set_uevent_suppress(&devcd->devcd_dev, false);
+	kobject_uevent(&devcd->devcd_dev.kobj, KOBJ_ADD);
 	INIT_DELAYED_WORK(&devcd->del_wk, devcd_del);
 	schedule_delayed_work(&devcd->del_wk, DEVCD_TIMEOUT);
 	mutex_unlock(&devcd->mutex);