From 82d340081b6f71237373d1452e3573a5a122794c Mon Sep 17 00:00:00 2001
From: Catalin Marinas <catalin.marinas@arm.com>
Date: Tue, 8 Dec 2015 17:39:15 +0000
Subject: [PATCH] arm64: Improve error reporting on set_pte_at() checks
Currently the BUG_ON() checks do not give enough information about the
PTEs being set. This patch changes BUG_ON to WARN_ONCE and dumps the
values of the old and new PTEs. In addition, the checks are only made if
the new PTE entry is valid.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Ming Lei <tom.leiming@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
---
arch/arm64/include/asm/pgtable.h | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 7e074f93f383f..63f52b55defe1 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -276,10 +276,14 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
* hardware updates of the pte (ptep_set_access_flags safely changes
* valid ptes without going through an invalid entry).
*/
- if (IS_ENABLED(CONFIG_DEBUG_VM) && IS_ENABLED(CONFIG_ARM64_HW_AFDBM) &&
- pte_valid(*ptep)) {
- BUG_ON(!pte_young(pte));
- BUG_ON(pte_write(*ptep) && !pte_dirty(pte));
+ if (IS_ENABLED(CONFIG_ARM64_HW_AFDBM) &&
+ pte_valid(*ptep) && pte_valid(pte)) {
+ VM_WARN_ONCE(!pte_young(pte),
+ "%s: racy access flag clearing: 0x%016llx -> 0x%016llx",
+ __func__, pte_val(*ptep), pte_val(pte));
+ VM_WARN_ONCE(pte_write(*ptep) && !pte_dirty(pte),
+ "%s: racy dirty state clearing: 0x%016llx -> 0x%016llx",
+ __func__, pte_val(*ptep), pte_val(pte));
}
set_pte(ptep, pte);
--
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