Re: [PATCH 6.2 regression fix] gpiolib: Fix using uninitialized lookup-flags on ACPI platforms #forregzbot

[Thorsten Leemhuis <regressions@xxxxxxxxxxxxx>]

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On 29.12.22 17:45, Hans de Goede wrote:
> Commit 8eb1f71e7acc ("gpiolib: consolidate GPIO lookups") refactors
> fwnode_get_named_gpiod() and gpiod_get_index() into a unified
> gpiod_find_and_request() helper.
> 
> The old functions both initialized their local lookupflags variable to
> GPIO_LOOKUP_FLAGS_DEFAULT, but the new code leaves it uninitialized.
> 
> This is a problem for at least ACPI platforms, where acpi_find_gpio()
> only does a bunch of *lookupflags |= GPIO_* statements and thus relies
> on the variable being initialized.
> 
> The variable not being initialized leads to:
> 
> 1. Potentially the wrong flags getting used
> 2. The check for conflicting lookup flags in gpiod_configure_flags():
>    "multiple pull-up, pull-down or pull-disable enabled, invalid config"
>    sometimes triggering, making the GPIO unavailable
> 
> Restore the initialization of lookupflags to GPIO_LOOKUP_FLAGS_DEFAULT
> to fix this.
> 
> Fixes: 8eb1f71e7acc ("gpiolib: consolidate GPIO lookups")
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> ---
> Note I'm not working and not reading work email until Monday January 9th.
> I hit this while doing some hobby stuff and I decided to send this out
> right away to avoid others potentially wasting time debugging this, but
> I will not see any replies until Monday January 9th.

Thanks for the report. To be sure below issue doesn't fall through the
cracks unnoticed, I'm adding it to regzbot, my Linux kernel regression
tracking bot:

#regzbot ^introduced 8eb1f71e7acc
#regzbot title gpiolib: potentially the wrong flags getting used
#regzbot fix: gpiolib: Fix using uninitialized lookup-flags on ACPI
platforms
#regzbot ignore-activity

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)

P.S.: As the Linux kernel's regression tracker I deal with a lot of
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