| From 34127b3632b21e5c391756e724b1198eb9917981 Mon Sep 17 00:00:00 2001 |
| From: Laurence de Bruxelles <lfdebrux@gmail.com> |
| Date: Sat, 1 Jan 2022 15:41:49 +0000 |
| Subject: rtc: pxa: fix null pointer dereference |
| |
| From: Laurence de Bruxelles <lfdebrux@gmail.com> |
| |
| commit 34127b3632b21e5c391756e724b1198eb9917981 upstream. |
| |
| With the latest stable kernel versions the rtc on the PXA based |
| Zaurus does not work, when booting I see the following kernel messages: |
| |
| pxa-rtc pxa-rtc: failed to find rtc clock source |
| pxa-rtc pxa-rtc: Unable to init SA1100 RTC sub-device |
| pxa-rtc: probe of pxa-rtc failed with error -2 |
| hctosys: unable to open rtc device (rtc0) |
| |
| I think this is because commit f2997775b111 ("rtc: sa1100: fix possible |
| race condition") moved the allocation of the rtc_device struct out of |
| sa1100_rtc_init and into sa1100_rtc_probe. This means that pxa_rtc_probe |
| also needs to do allocation for the rtc_device struct, otherwise |
| sa1100_rtc_init will try to dereference a null pointer. This patch adds |
| that allocation by copying how sa1100_rtc_probe in |
| drivers/rtc/rtc-sa1100.c does it; after the IRQs are set up a managed |
| rtc_device is allocated. |
| |
| I've tested this patch with `qemu-system-arm -machine akita` and with a |
| real Zaurus SL-C1000 applied to 4.19, 5.4, and 5.10. |
| |
| Signed-off-by: Laurence de Bruxelles <lfdebrux@gmail.com> |
| Fixes: f2997775b111 ("rtc: sa1100: fix possible race condition") |
| Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> |
| Link: https://lore.kernel.org/r/20220101154149.12026-1-lfdebrux@gmail.com |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/rtc/rtc-pxa.c | 4 ++++ |
| 1 file changed, 4 insertions(+) |
| |
| --- a/drivers/rtc/rtc-pxa.c |
| +++ b/drivers/rtc/rtc-pxa.c |
| @@ -330,6 +330,10 @@ static int __init pxa_rtc_probe(struct p |
| if (sa1100_rtc->irq_alarm < 0) |
| return -ENXIO; |
| |
| + sa1100_rtc->rtc = devm_rtc_allocate_device(&pdev->dev); |
| + if (IS_ERR(sa1100_rtc->rtc)) |
| + return PTR_ERR(sa1100_rtc->rtc); |
| + |
| pxa_rtc->base = devm_ioremap(dev, pxa_rtc->ress->start, |
| resource_size(pxa_rtc->ress)); |
| if (!pxa_rtc->base) { |
