Re: [PATCH] powerpc/entry: Fix double accounting of user time on interrupt entry

[Christophe Leroy (CS GROUP)]

Hi Aboorva,

Le 02/09/2026 à 21:44, Aboorva Devarajan a écrit :
> The history is as follows:
>
> Commit 09a9d3a8499d ("powerpc: introduce arch_enter_from_user_mode")
> introduced the arch_enter_from_user_mode() function with the accounting,
> but the function was not called at that point. Commit 893082ac769b
> ("powerpc: Prepare for IRQ entry exit") introduced arch_interrupt_enter_prepare()
> and copied the accounting from interrupt_enter_prepare() into it, but the
> new helper was not used either. Both changes were preparatory and did not
> change the accounting behavior.
>
> Commit bee25f97ad24 ("powerpc: Enable GENERIC_ENTRY feature") made both paths
> active. The syscall path removed its open-coded account_cpu_user_entry() and
> started accounting through arch_enter_from_user_mode(). But the interrupt path
> started using arch_interrupt_enter_prepare() followed by irqentry_enter(),
> which also invokes arch_enter_from_user_mode(), while the accounting in
> arch_interrupt_enter_prepare() remained. This resulted in the same user-time
> interval being accounted twice for interrupts taken from user mode.
>
> I used bee25f97ad24 ("powerpc: Enable GENERIC_ENTRY feature") as the Fixes
> tag because 893082ac769b only introduced the accounting call while
> arch_interrupt_enter_prepare() was unused. bee25f97ad24 is where the duplicate
> accounting actually became functional.
>
> Would it be ok to keep bee25f97ad24 as the Fixes tag? Please let me know if
> you think 893082ac769b would be more appropriate.

Ok, lets keep bee25f97ad24, I guess a bisect would land here. Anyway 
they all appear for the first time in v7.2

Christophe