Messages in this thread Patch in this message | | | Date | Tue, 2 Jul 2019 16:13:02 -0700 | Subject | [PATCH] arm64: mm: Fix dead assignment of old_pte | From | Nathan Huckleberry <> |
| |
When analyzed with the clang static analyzer the following warning occurs
line 251, column 2 Value stored to 'old_pte' is never read
This warning is repeated every time pgtable.h is included by another file and produces ~3500 extra warnings.
Moving old_pte into preprocessor guard.
Cc: clang-built-linux@googlegroups.com Signed-off-by: Nathan Huckleberry <nhuck@google.com> --- arch/arm64/include/asm/pgtable.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index fca26759081a..42ca4fc67f27 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -238,8 +238,6 @@ extern void __sync_icache_dcache(pte_t pteval); static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte) { - pte_t old_pte; - if (pte_present(pte) && pte_user_exec(pte) && !pte_special(pte)) __sync_icache_dcache(pte); @@ -248,8 +246,11 @@ 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) + pte_t old_pte; + old_pte = READ_ONCE(*ptep); - if (IS_ENABLED(CONFIG_DEBUG_VM) && pte_valid(old_pte) && pte_valid(pte) && + if (pte_valid(old_pte) && pte_valid(pte) && (mm == current->active_mm || atomic_read(&mm->mm_users) > 1)) { VM_WARN_ONCE(!pte_young(pte), "%s: racy access flag clearing: 0x%016llx -> 0x%016llx", @@ -258,6 +259,7 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, "%s: racy dirty state clearing: 0x%016llx -> 0x%016llx", __func__, pte_val(old_pte), pte_val(pte)); } + #endif set_pte(ptep, pte); } -- 2.22.0.410.gd8fdbe21b5-goog
| |