The change [1] missed ARM architecture when fixing major fault accounting
for page fault retry under per-VMA lock. Add missing code to fix ARM
architecture fault accounting.
[1] 46e714c729c8 ("arch/mm/fault: fix major fault accounting when retrying under per-VMA lock")
Fixes: 12214eba1992 ("mm: handle read faults under the VMA lock")
Reported-by: Russell King (Oracle) <[email protected]>
Signed-off-by: Suren Baghdasaryan <[email protected]>
---
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)) {
--
2.43.0.429.g432eaa2c6b-goog
On Mon, 22 Jan 2024 22:43:05 -0800 Suren Baghdasaryan <[email protected]> wrote:
> The change [1] missed ARM architecture when fixing major fault accounting
> for page fault retry under per-VMA lock. Add missing code to fix ARM
> architecture fault accounting.
>
> [1] 46e714c729c8 ("arch/mm/fault: fix major fault accounting when retrying under per-VMA lock")
>
> Fixes: 12214eba1992 ("mm: handle read faults under the VMA lock")
What are the userspace-visible runtime effects of this change?
Is a cc:stable backport desirable?
> Reported-by: Russell King (Oracle) <[email protected]>
> Signed-off-by: Suren Baghdasaryan <[email protected]>
On Thu, Jan 25, 2024 at 6:04 PM Andrew Morton <[email protected]> wrote:
>
> On Mon, 22 Jan 2024 22:43:05 -0800 Suren Baghdasaryan <[email protected]> wrote:
>
> > The change [1] missed ARM architecture when fixing major fault accounting
> > for page fault retry under per-VMA lock. Add missing code to fix ARM
> > architecture fault accounting.
> >
> > [1] 46e714c729c8 ("arch/mm/fault: fix major fault accounting when retrying under per-VMA lock")
> >
> > Fixes: 12214eba1992 ("mm: handle read faults under the VMA lock")
>
> What are the userspace-visible runtime effects of this change?
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]. I can re-send the
patch with the full description from [3] if needed.
>
> Is a cc:stable backport desirable?
Yes, I guess since [2] was merged in 6.7, cc-ing stable would be desirable.
Please let me know if you want me to re-send the patch with full
description and CC'ing stable.
[2] https://lore.kernel.org/all/[email protected]/
[3] https://lore.kernel.org/all/[email protected]/
>
> > Reported-by: Russell King (Oracle) <[email protected]>
> > Signed-off-by: Suren Baghdasaryan <[email protected]>
Hello:
This patch was applied to riscv/linux.git (fixes)
by Andrew Morton <[email protected]>:
On Mon, 22 Jan 2024 22:43:05 -0800 you wrote:
> The change [1] missed ARM architecture when fixing major fault accounting
> for page fault retry under per-VMA lock. Add missing code to fix ARM
> architecture fault accounting.
>
> [1] 46e714c729c8 ("arch/mm/fault: fix major fault accounting when retrying under per-VMA lock")
>
> Fixes: 12214eba1992 ("mm: handle read faults under the VMA lock")
>
> [...]
Here is the summary with links:
- [1/1] arch/arm/mm: fix major fault accounting when retrying under per-VMA lock
https://git.kernel.org/riscv/c/e870920bbe68
You are awesome, thank you!
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