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: [email protected] Signed-off-by: Nathan Huckleberry <[email protected]> --- Changes from v1 -> v2 * Added scope to avoid [-Wdeclaration-after-statement] arch/arm64/include/asm/pgtable.h | 27 ++++++++++++++++----------- 1 file changed, 16 insertions(+), 11 deletions(-) diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index fca26759081a..12b7f08db40d 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); @@ -248,16 +246,23 @@ 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). */ - old_pte = READ_ONCE(*ptep); - if (IS_ENABLED(CONFIG_DEBUG_VM) && 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", - __func__, pte_val(old_pte), pte_val(pte)); - VM_WARN_ONCE(pte_write(old_pte) && !pte_dirty(pte), - "%s: racy dirty state clearing: 0x%016llx -> 0x%016llx", - __func__, pte_val(old_pte), pte_val(pte)); + #if IS_ENABLED(CONFIG_DEBUG_VM) + { + pte_t old_pte; + + old_pte = READ_ONCE(*ptep); + 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", + __func__, pte_val(old_pte), pte_val(pte)); + VM_WARN_ONCE(pte_write(old_pte) && !pte_dirty(pte), + "%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
