Messages in this thread | | | Date | Tue, 22 Feb 2022 15:06:07 +0100 | Subject | Re: [RFT PATCH 0/3] Fix kfree() of const memory on setting driver_override | From | Krzysztof Kozlowski <> |
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On 22/02/2022 14:51, Rasmus Villemoes wrote: > On 22/02/2022 14.27, Krzysztof Kozlowski wrote: >> Hi, >> >> Drivers still seem to use driver_override incorrectly. Perhaps my old >> patch makes sense now? >> https://lore.kernel.org/all/1550484960-2392-3-git-send-email-krzk@kernel.org/ >> >> Not tested - please review and test (e.g. by writing to dirver_override >> sysfs entry with KASAN enabled). > > Perhaps it would make sense to update the core code to release using > kfree_const(), allowing drivers to set the initial value with > kstrdup_const(). Drivers that currently use kstrdup() or kasprintf() > will continue to work [but if they kstrdup() a string literal they could > be changed to use kstrdup_const].
The core here means several buses, so the change would not be that small. However I don't see the reason why "driver_override" is special and should be freed with kfree_const() while most of other places don't use it.
The driver_override field definition is here obvious: "char *", so any assignments of "const char *" are logically wrong (although GCC does not warn of this literal string const discarding). Adding kfree_const() is hiding the problem - someone did not read the definition of assigned field.
Best regards, Krzysztof
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