diff options
| -rw-r--r-- | arch/x86/kernel/ftrace.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 38c798b1dbd2..9f033dfd2766 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -761,6 +761,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) unsigned long end_offset; unsigned long op_offset; unsigned long offset; + unsigned long npages; unsigned long size; unsigned long retq; unsigned long *ptr; @@ -793,6 +794,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) return 0; *tramp_size = size + RET_SIZE + sizeof(void *); + npages = DIV_ROUND_UP(*tramp_size, PAGE_SIZE); /* Copy ftrace_caller onto the trampoline memory */ ret = probe_kernel_read(trampoline, (void *)start_offset, size); @@ -837,6 +839,12 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) /* ALLOC_TRAMP flags lets us know we created it */ ops->flags |= FTRACE_OPS_FL_ALLOC_TRAMP; + /* + * Module allocation needs to be completed by making the page + * executable. The page is still writable, which is a security hazard, + * but anyhow ftrace breaks W^X completely. + */ + set_memory_x((unsigned long)trampoline, npages); return (unsigned long)trampoline; fail: tramp_free(trampoline, *tramp_size); |