Messages in this thread | | | Date | Fri, 03 Feb 2023 15:32:28 +0100 | From | "Arnd Bergmann" <> | Subject | Re: [PATCH] locking/atomic: cmpxchg: Make __generic_cmpxchg_local compare against zero-extended 'old' value |
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On Wed, Feb 1, 2023, at 19:39, Matt Evans wrote: > __generic_cmpxchg_local takes unsigned long old/new arguments which > might end up being up-cast from smaller signed types (which will > sign-extend). The loaded compare value must be compared against a > truncated smaller type, so down-cast appropriately for each size. > > The issue is apparent on 64-bit machines with code, such as > atomic_dec_unless_positive(), that sign-extends from int. > > 64-bit machines generally don't use the generic cmpxchg but > development/early ports might make use of it, so make it correct. > > Signed-off-by: Matt Evans <mev@rivosinc.com> > ---
Applied to the asm-generic tree for 6.3, thanks
Arnd
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