This is a note to let you know that I've just added the patch titled ftrace: Fix memleak when unregistering dynamic ops when tracing disabled to the 4.13-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ftrace-fix-memleak-when-unregistering-dynamic-ops-when-tracing-disabled.patch and it can be found in the queue-4.13 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >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: ftrace: Fix memleak when unregistering dynamic ops when tracing disabled From: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> commit edb096e00724f02db5f6ec7900f3bbd465c6c76f upstream. 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 Fixes: 12cce594fa ("ftrace/x86: Allow !CONFIG_PREEMPT dynamic ops to use allocated trampolines") Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/trace/ftrace.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2828,13 +2828,14 @@ static int ftrace_shutdown(struct ftrace if (!command || !ftrace_enabled) { /* - * If these are per_cpu ops, they still need their - * per_cpu field freed. Since, function tracing is + * If these are dynamic or per_cpu 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_PER_CPU) - per_cpu_ops_free(ops); + if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) + goto free_ops; + return 0; } @@ -2900,6 +2901,7 @@ static int ftrace_shutdown(struct ftrace if (IS_ENABLED(CONFIG_PREEMPT)) synchronize_rcu_tasks(); + free_ops: arch_ftrace_trampoline_free(ops); if (ops->flags & FTRACE_OPS_FL_PER_CPU) Patches currently in stable-queue which might be from rostedt@xxxxxxxxxxx are queue-4.13/ftrace-fix-debug-preempt-config-name-in-stack_tracer_-en-dis-able.patch queue-4.13/tracing-add-barrier-to-trace_printk-buffer-nesting-modification.patch queue-4.13/ftrace-fix-memleak-when-unregistering-dynamic-ops-when-tracing-disabled.patch queue-4.13/tracing-apply-trace_clock-changes-to-instance-max-buffer.patch queue-4.13/ftrace-fix-selftest-goto-location-on-error.patch queue-4.13/tracing-fix-clear-of-recorded_tgid-flag-when-disabling-trace-event.patch