Messages in this thread | | | From | Arnd Bergmann <> | Date | Wed, 28 Jun 2017 12:34:28 +0200 | Subject | Re: [RFC PATCH] char: misc: Init misc->list in a safe way |
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On Wed, Jun 28, 2017 at 7:18 AM, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > On Wed, Jun 28, 2017 at 09:54:32AM +0800, Orson Zhai wrote: >> We found the device is "fm". We highly suspect that fm driver call >> misc_register twice and reinitialize list to make ->pre & ->next >> pointing to himself. >> >> Meanwhile, we checked fm driver and found nothing obviously wrong in the code. > > Do you have a pointer to this driver? Is it in the kernel tree?
I found a version of some spreadtrum FM driver in the sources for the Samsung Galaxy J3, this is the driver https://pastebin.com/p7Y7xQNE
The driver has a single static 'misc_device' structure that will get registered each time the probe() function is called. The driver also supports both a static platform_device definition (which a proper driver should not have, the device should always be created either from platform code or from DT), and probing from device tree.
If the DT has multiple "sprd,sprd_fm" device nodes, or a driver is lacking the "#ifndef CONFIG_OF" guard around the static platform device, it should always crash with the described symptom, but I don't see why it would only happen after many hours of boot testing.
Arnd
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