On Tue, Feb 20, 2024 at 11:02 AM Suren Baghdasaryan <surenb@xxxxxxxxxx> wrote:
>
> The change [1] missed ARM architecture when fixing major fault accounting
> for page fault retry under per-VMA lock.
>
> The user-visible effects is that it restores correct major fault
> accounting that was broken after [2] was merged in 6.7 kernel. The
> more detailed description is in [3] and this patch simply adds the
> same fix to ARM architecture which I missed in [3].
>
> Add missing code to fix ARM architecture fault accounting.
>
> [1] 46e714c729c8 ("arch/mm/fault: fix major fault accounting when retrying under per-VMA lock")
> [2] https://lore.kernel.org/all/20231006195318.4087158-6-willy@xxxxxxxxxxxxx/
> [3] https://lore.kernel.org/all/20231226214610.109282-1-surenb@xxxxxxxxxx/
>
> Link: https://lkml.kernel.org/r/20240123064305.2829244-1-surenb@xxxxxxxxxx
> Fixes: 12214eba1992 ("mm: handle read faults under the VMA lock")
> Reported-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx>
> Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
> Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
> Cc: Andy Lutomirski <luto@xxxxxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
> Cc: Gerald Schaefer <gerald.schaefer@xxxxxxxxxxxxx>
> Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Sorry, missed the prerequisite patch. Please ignore this one and see
the next patchset I sent with 2 patches in it:
https://lore.kernel.org/all/20240220190351.39815-1-surenb@xxxxxxxxxx/
https://lore.kernel.org/all/20240220190351.39815-2-surenb@xxxxxxxxxx/
Thanks,
Suren.
> ---
> arch/arm/mm/fault.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
> index e96fb40b9cc3..07565b593ed6 100644
> --- a/arch/arm/mm/fault.c
> +++ b/arch/arm/mm/fault.c
> @@ -298,6 +298,8 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
> goto done;
> }
> count_vm_vma_lock_event(VMA_LOCK_RETRY);
> + if (fault & VM_FAULT_MAJOR)
> + flags |= FAULT_FLAG_TRIED;
>
> /* Quick path to respond to signals */
> if (fault_signal_pending(fault, regs)) {
> --
> 2.44.0.rc0.258.g7320e95886-goog
>
