Patch "ptp: unregister virtual clocks when unregistering physical clock." has been added to the 5.17-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    ptp: unregister virtual clocks when unregistering physical clock.

to the 5.17-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ptp-unregister-virtual-clocks-when-unregistering-phy.patch
and it can be found in the queue-5.17 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 408778f838ddd4a32a397789d3bcd9fd8f4c4c1b
Author: Miroslav Lichvar <mlichvar@xxxxxxxxxx>
Date:   Wed Feb 2 10:33:55 2022 +0100

    ptp: unregister virtual clocks when unregistering physical clock.
    
    [ Upstream commit bfcbb76b0f595ea9ede9f7a218086fef85242f10 ]
    
    When unregistering a physical clock which has some virtual clocks,
    unregister the virtual clocks with it.
    
    This fixes the following oops, which can be triggered by unloading
    a driver providing a PTP clock when it has enabled virtual clocks:
    
    BUG: unable to handle page fault for address: ffffffffc04fc4d8
    Oops: 0000 [#1] PREEMPT SMP NOPTI
    RIP: 0010:ptp_vclock_read+0x31/0xb0
    Call Trace:
     timecounter_read+0xf/0x50
     ptp_vclock_refresh+0x2c/0x50
     ? ptp_clock_release+0x40/0x40
     ptp_aux_kworker+0x17/0x30
     kthread_worker_fn+0x9b/0x240
     ? kthread_should_park+0x30/0x30
     kthread+0xe2/0x110
     ? kthread_complete_and_exit+0x20/0x20
     ret_from_fork+0x22/0x30
    
    Fixes: 73f37068d540 ("ptp: support ptp physical/virtual clocks conversion")
    Signed-off-by: Miroslav Lichvar <mlichvar@xxxxxxxxxx>
    Acked-by: Richard Cochran <richardcochran@xxxxxxxxx>
    Cc: Yangbo Lu <yangbo.lu@xxxxxxx>
    Cc: Yang Yingliang <yangyingliang@xxxxxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index 0e4bc8b9329d..b6f2cfd15dd2 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -317,11 +317,18 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
 }
 EXPORT_SYMBOL(ptp_clock_register);
 
+static int unregister_vclock(struct device *dev, void *data)
+{
+	struct ptp_clock *ptp = dev_get_drvdata(dev);
+
+	ptp_vclock_unregister(info_to_vclock(ptp->info));
+	return 0;
+}
+
 int ptp_clock_unregister(struct ptp_clock *ptp)
 {
 	if (ptp_vclock_in_use(ptp)) {
-		pr_err("ptp: virtual clock in use\n");
-		return -EBUSY;
+		device_for_each_child(&ptp->dev, NULL, unregister_vclock);
 	}
 
 	ptp->defunct = 1;