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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org,
	stable@vger.kernel.org
Cc: Suren Baghdasaryan <surenb@google.com>,
	Russell King <rmk+kernel@armlinux.org.uk>,
	Alexander Gordeev <agordeev@linux.ibm.com>,
	Andy Lutomirski <luto@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Christophe Leroy <christophe.leroy@csgroup.eu>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Gerald Schaefer <gerald.schaefer@linux.ibm.com>,
	Matthew Wilcox <willy@infradead.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Will Deacon <will@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.7 60/61] arch/arm/mm: fix major fault accounting when retrying under per-VMA lock
Date: Wed, 13 Mar 2024 12:32:35 -0400
Message-ID: <20240313163236.613880-61-sashal@kernel.org>
In-Reply-To: <20240313163236.613880-1-sashal@kernel.org>
References: <20240313163236.613880-1-sashal@kernel.org>
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From: Suren Baghdasaryan <surenb@google.com>

[ Upstream commit e870920bbe68e52335a4c31a059e6af6a9a59dbb ]

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@infradead.org/
[3] https://lore.kernel.org/all/20231226214610.109282-1-surenb@google.com/

Link: https://lkml.kernel.org/r/20240123064305.2829244-1-surenb@google.com
Fixes: 12214eba1992 ("mm: handle read faults under the VMA lock")
Reported-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 e96fb40b9cc32..07565b593ed68 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