From: Steven Rostedt (VMware) Date: Fri, 1 Sep 2017 16:18:28 +0000 (-0400) Subject: ftrace: Fix memleak when unregistering dynamic ops when tracing disabled X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=edb096e00724f02db5f6ec7900f3bbd465c6c76f;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git 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: [] kmemleak_vmalloc+0x85/0xf0 [] __vmalloc_node_range+0x281/0x3e0 [] module_alloc+0x4f/0x90 [] arch_ftrace_update_trampoline+0x160/0x420 [] ftrace_startup+0xe7/0x300 [] register_ftrace_function+0x72/0x90 [] trace_selftest_ops+0x204/0x397 [] trace_selftest_startup_function+0x394/0x624 [] run_tracer_selftest+0x15c/0x1d7 [] init_trace_selftests+0x75/0x192 [] do_one_initcall+0x90/0x1e2 [] kernel_init_freeable+0x350/0x3fe [] kernel_init+0x13/0x122 [] ret_from_fork+0x2a/0x40 [] 0xffffffffffffffff Cc: stable@vger.kernel.org Fixes: 12cce594fa ("ftrace/x86: Allow !CONFIG_PREEMPT dynamic ops to use allocated trampolines") Signed-off-by: Steven Rostedt (VMware) --- diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 165b149ccb1a..6abfafd7f173 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2828,13 +2828,14 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command) 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_ops *ops, int command) if (IS_ENABLED(CONFIG_PREEMPT)) synchronize_rcu_tasks(); + free_ops: arch_ftrace_trampoline_free(ops); if (ops->flags & FTRACE_OPS_FL_PER_CPU)