kprobes/x86: Fix to set RWX bits correctly before releasing trampoline
authorMasami Hiramatsu <mhiramat@kernel.org>
Thu, 25 May 2017 10:38:17 +0000 (19:38 +0900)
committerSteven Rostedt (VMware) <rostedt@goodmis.org>
Sat, 27 May 2017 02:37:00 +0000 (22:37 -0400)
commitc93f5cf571e7795f97d49ef51b766cf25e328545
treedbe64f0e9bf5a26ece23376aa925a8c13be817fe
parentf9797c2f20c0160edd718aa467101f3301e57e59
kprobes/x86: Fix to set RWX bits correctly before releasing trampoline

Fix kprobes to set(recover) RWX bits correctly on trampoline
buffer before releasing it. Releasing readonly page to
module_memfree() crash the kernel.

Without this fix, if kprobes user register a bunch of kprobes
in function body (since kprobes on function entry usually
use ftrace) and unregister it, kernel hits a BUG and crash.

Link: http://lkml.kernel.org/r/149570868652.3518.14120169373590420503.stgit@devbox
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: d0381c81c2f7 ("kprobes/x86: Set kprobes pages read-only")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
arch/x86/kernel/kprobes/core.c
kernel/kprobes.c