On Fri, 22 Sep 2017 13:24:11 +0200
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> The patch below does not apply to the 4.4-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@xxxxxxxxxxxxxxx>.
>
> thanks,
>
Hi Greg,
Can you use this patch instead. I just tested it out, it appears to
work fine.
-- Steve
------------------ original commit in Linus's tree ------------------
>From edb096e00724f02db5f6ec7900f3bbd465c6c76f Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
Date: Fri, 1 Sep 2017 12:18:28 -0400
Subject: [PATCH] ftrace: Fix memleak when unregistering dynamic ops when
tracing disabled
If function tracing is disabled by the user via the function-trace option or
the proc sysctl file, and a ftrace_ops that was allocated on the heap is
unregistered, then the shutdown code exits out without doing the proper
clean up. This was found via kmemleak and running the ftrace selftests, as
one of the tests unregisters with function tracing disabled.
# cat kmemleak
unreferenced object 0xffffffffa0020000 (size 4096):
comm "swapper/0", pid 1, jiffies 4294668889 (age 569.209s)
hex dump (first 32 bytes):
55 ff 74 24 10 55 48 89 e5 ff 74 24 18 55 48 89 U.t$.UH...t$.UH.
e5 48 81 ec a8 00 00 00 48 89 44 24 50 48 89 4c .H......H.D$PH.L
backtrace:
[<ffffffff81d64665>] kmemleak_vmalloc+0x85/0xf0
[<ffffffff81355631>] __vmalloc_node_range+0x281/0x3e0
[<ffffffff8109697f>] module_alloc+0x4f/0x90
[<ffffffff81091170>] arch_ftrace_update_trampoline+0x160/0x420
[<ffffffff81249947>] ftrace_startup+0xe7/0x300
[<ffffffff81249bd2>] register_ftrace_function+0x72/0x90
[<ffffffff81263786>] trace_selftest_ops+0x204/0x397
[<ffffffff82bb8971>] trace_selftest_startup_function+0x394/0x624
[<ffffffff81263a75>] run_tracer_selftest+0x15c/0x1d7
[<ffffffff82bb83f1>] init_trace_selftests+0x75/0x192
[<ffffffff81002230>] do_one_initcall+0x90/0x1e2
[<ffffffff82b7d620>] kernel_init_freeable+0x350/0x3fe
[<ffffffff81d61ec3>] kernel_init+0x13/0x122
[<ffffffff81d72c6a>] ret_from_fork+0x2a/0x40
[<ffffffffffffffff>] 0xffffffffffffffff
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 12cce594fa ("ftrace/x86: Allow !CONFIG_PREEMPT dynamic ops to use allocated trampolines")
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Index: linux-test.git/kernel/trace/ftrace.c
===================================================================
--- linux-test.git.orig/kernel/trace/ftrace.c
+++ linux-test.git/kernel/trace/ftrace.c
@@ -2667,13 +2667,14 @@ static int ftrace_shutdown(struct ftrace
if (!command || !ftrace_enabled) {
/*
- * If these are control ops, they still need their
- * per_cpu field freed. Since, function tracing is
+ * If these are dynamic or control ops, they still
+ * need their data freed. Since, function tracing is
* not currently active, we can just free them
* without synchronizing all CPUs.
*/
- if (ops->flags & FTRACE_OPS_FL_CONTROL)
- control_ops_free(ops);
+ if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_CONTROL))
+ goto free_ops;
+
return 0;
}
@@ -2728,6 +2729,7 @@ static int ftrace_shutdown(struct ftrace
if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_CONTROL)) {
schedule_on_each_cpu(ftrace_sync);
+ free_ops:
arch_ftrace_trampoline_free(ops);
if (ops->flags & FTRACE_OPS_FL_CONTROL)