[PATCH 5.16 0468/1017] ptp: unregister virtual clocks when unregistering physical clock.

Greg Kroah-Hartman
2022-04-05T12:39:22Z

From: Miroslav Lichvar <mlichvar@redhat.com>

[ 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@redhat.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Cc: Yangbo Lu <yangbo.lu@nxp.com>
Cc: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/ptp/ptp_clock.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

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;
--
2.34.1