On Tue, Jun 16, 2020 at 12:42:30PM +0200, Christoph Hellwig wrote:
> On Tue, Jun 16, 2020 at 12:40:32PM +0200, Peter Zijlstra wrote:
> > On Tue, Jun 16, 2020 at 12:33:13PM +0200, Christoph Hellwig wrote:
> > > sorry, s/ftrace/kprobes/. See my updated branch here:
> > >
> > > http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/module_alloc-cleanup
> >
> > Ah the insn slot page, yes. Didn't you just loose VM_FLUSH_RESET_PERMS
> > there?
>
> Yes, we did. vmalloc_exec had it, but given that module_alloc didn't
> allocate executable on x86 it didn't. I guess we should make sure it
> is set by the low-level vmalloc code if exec permissions are set to
> sort this mess out.
I think something like this should solve the issue:
--
diff --git a/arch/x86/include/asm/module.h b/arch/x86/include/asm/module.h
index e988bac0a4a1c3..716e4de44a8e78 100644
--- a/arch/x86/include/asm/module.h
+++ b/arch/x86/include/asm/module.h
@@ -13,4 +13,6 @@ struct mod_arch_specific {
#endif
};
+void *module_alloc_prot(unsigned long size, pgprot_t prot);
+
#endif /* _ASM_X86_MODULE_H */
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index 34b153cbd4acb4..4db6e655120960 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -65,8 +65,10 @@ static unsigned long int get_module_load_offset(void)
}
#endif
-void *module_alloc(unsigned long size)
+void *module_alloc_prot(unsigned long size, pgprot_t prot)
{
+ unsigned int flags = (pgprot_val(prot) & _PAGE_NX) ?
+ 0 : VM_FLUSH_RESET_PERMS;
void *p;
if (PAGE_ALIGN(size) > MODULES_LEN)
@@ -75,7 +77,7 @@ void *module_alloc(unsigned long size)
p = __vmalloc_node_range(size, MODULE_ALIGN,
MODULES_VADDR + get_module_load_offset(),
MODULES_END, GFP_KERNEL,
- PAGE_KERNEL, 0, NUMA_NO_NODE,
+ prot, flags, NUMA_NO_NODE,
__builtin_return_address(0));
if (p && (kasan_module_alloc(p, size) < 0)) {
vfree(p);
@@ -85,6 +87,11 @@ void *module_alloc(unsigned long size)
return p;
}
+void *module_alloc(unsigned long size)
+{
+ return module_alloc_prot(size, PAGE_KERNEL);
+}
+
#ifdef CONFIG_X86_32
int apply_relocate(Elf32_Shdr *sechdrs,
const char *strtab,
