lkml.org 
[lkml]   [2022]   [Jan]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.4 298/320] rtc: pxa: fix null pointer dereference
    Date
    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) {

    \
     
     \ /
      Last update: 2022-01-24 22:09    [W:4.055 / U:0.468 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site