And besides, it looks as if the code was meant to flush the entire TLB in some cases (e.g., if pgd_none_or_clear_bad() is true).
On 4/26/17, 4:56 PM, "Nadav Amit" <[email protected]> wrote: It may be benign, but I don’t think that flushing the TLB without holding the ptl or the mmap_sem (for no apparent reason) is a good practice. On 4/22/17, 12:01 AM, "Andy Lutomirski" <[email protected]> wrote: mark_screen_rdonly() is the last remaining caller of flush_tlb(). flush_tlb_mm_range() is potentially faster and isn't obsolete. Compile-tested only because I don't know whether software that uses this mechanism even exists. Cc: Rik van Riel <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Nadav Amit <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Sasha Levin <[email protected]> Cc: Andrew Morton <[email protected]> Signed-off-by: Andy Lutomirski <[email protected]> --- arch/x86/kernel/vm86_32.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c index 23ee89ce59a9..3eda76b3c835 100644 --- a/arch/x86/kernel/vm86_32.c +++ b/arch/x86/kernel/vm86_32.c @@ -193,7 +193,7 @@ static void mark_screen_rdonly(struct mm_struct *mm) pte_unmap_unlock(pte, ptl); out: up_write(&mm->mmap_sem); - flush_tlb(); + flush_tlb_mm_range(mm, 0xA0000, 0xA0000 + 32*PAGE_SIZE, 0UL); } -- 2.9.3
