From f83b4f8860046e0f5244eef35b25fc3e405d7fee Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Thu, 23 May 2019 11:22:55 +0100 Subject: [PATCH] arm64/kprobes: set VM_FLUSH_RESET_PERMS on kprobe instruction pages In order to avoid transient inconsistencies where freed code pages are remapped writable while stale TLB entries still exist on other cores, mark the kprobes text pages with the VM_FLUSH_RESET_PERMS attribute. This instructs the core vmalloc code not to defer the TLB flush when this region is unmapped and returned to the page allocator. Acked-by: Will Deacon Signed-off-by: Ard Biesheuvel Signed-off-by: Catalin Marinas --- arch/arm64/kernel/probes/kprobes.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c index 88ce502..bd5dfff 100644 --- a/arch/arm64/kernel/probes/kprobes.c +++ b/arch/arm64/kernel/probes/kprobes.c @@ -122,8 +122,10 @@ void *alloc_insn_page(void) void *page; page = vmalloc_exec(PAGE_SIZE); - if (page) + if (page) { set_memory_ro((unsigned long)page, 1); + set_vm_flush_reset_perms(page); + } return page; } -- 2.7.4