Re: [WARNING] x86/mm: Found insecure W+X mapping at address ..

[Steven Rostedt]

On Tue, 23 May 2017 22:48:19 +0200 (CEST)
Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:


> It's not KPROBES, it's the new fangled ftrace trampoline code. I
> added a few printks. All the leaked W+X mappings are allocated via
> this callchain:

The trampoline code isn't new. But it has new users because of the
introduction to synchronize_rcu_tasks(), and there was a bug I fixed in
-rc2 that moved it down because the test was run before
synchronize_rcu_tasks() was functional.

Is this still a bug in rc2?

-- Steve


> 
> [    2.620465]  module_alloc+0x8e/0xa0
> [    2.620764]  ? __fentry__+0x10/0x10
> [    2.621049]  arch_ftrace_update_trampoline+0x9f/0x220
> [    2.621453]  ? ftrace_caller+0x64/0x64
> [    2.621754]  ? __fentry__+0x10/0x10
> [    2.622047]  ftrace_startup+0x90/0x200
> [    2.622352]  register_ftrace_function+0x50/0x70
> [    2.622725]  function_trace_init+0x6d/0xa0
> [    2.623057]  trace_selftest_startup_function+0x63/0x4a8
> [    2.623477]  run_tracer_selftest+0xfe/0x16c
> [    2.623813]  init_trace_selftests+0x5d/0x103
> [    2.624163]  ? set_tracepoint_printk+0x3d/0x3d
> [    2.624525]  do_one_initcall+0x44/0x170
> [    2.624845]  kernel_init_freeable+0x1ff/0x287
> [    2.625199]  ? rest_init+0x140/0x140
> [    2.625491]  kernel_init+0xe/0x110
> [    2.625775]  ret_from_fork+0x2e/0x40
> 
> Thanks,
> 
> 	tglx