> From: [email protected] > To: [email protected], [email protected] > Cc: [email protected], [email protected], [email protected], "Shu > Wang" <[email protected]> > Sent: Tuesday, September 12, 2017 10:14:54 AM > Subject: [PATCH] ftrace: fix kmemleak in unregister_ftrace_graph > > From: Shu Wang <[email protected]> > > The trampoline allocated by function tracer was > overwrite by function_graph tracer, and cause > memory leak. The save_global_trampoline should > save previous trampoline in register_ftrace_graph > and restore it in unregister_ftrace_graph. But > as it implemented, save_global_trampoline was only > used in unregister_ftrace_graph as default value 0, > and overwrite the previous trampoline's value. > > kmmeleak backtrace: > kmemleak_vmalloc+0x77/0xc0 > __vmalloc_node_range+0x1b5/0x2c0 > module_alloc+0x7c/0xd0 > arch_ftrace_update_trampoline+0xb5/0x290 > ftrace_startup+0x78/0x210 > register_ftrace_function+0x8b/0xd0 > function_trace_init+0x4f/0x80 > tracing_set_tracer+0xe6/0x170 > tracing_set_trace_write+0x90/0xd0 > __vfs_write+0x37/0x170 > vfs_write+0xb2/0x1b0 > SyS_write+0x55/0xc0 > do_syscall_64+0x67/0x180 > return_from_SYSCALL_64+0x0/0x6a > > Signed-off-by: Shu Wang <[email protected]> > --- > kernel/trace/ftrace.c | 14 -------------- > 1 file changed, 14 deletions(-) > > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > index 6abfafd7f173..8319e09e15b9 100644 > --- a/kernel/trace/ftrace.c > +++ b/kernel/trace/ftrace.c > @@ -4954,9 +4954,6 @@ static char ftrace_graph_buf[FTRACE_FILTER_SIZE] > __initdata; > static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata; > static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer); > > -static unsigned long save_global_trampoline; > -static unsigned long save_global_flags; > - > static int __init set_graph_function(char *str) > { > strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE); > @@ -6808,17 +6805,6 @@ void unregister_ftrace_graph(void) > unregister_pm_notifier(&ftrace_suspend_notifier); > unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL); > > -#ifdef CONFIG_DYNAMIC_FTRACE > - /* > - * Function graph does not allocate the trampoline, but > - * other global_ops do. We need to reset the ALLOC_TRAMP flag > - * if one was used. > - */ > - global_ops.trampoline = save_global_trampoline; > - if (save_global_flags & FTRACE_OPS_FL_ALLOC_TRAMP) > - global_ops.flags |= FTRACE_OPS_FL_ALLOC_TRAMP; > -#endif > - > out: > mutex_unlock(&ftrace_lock); > } > -- > 2.13.5 > >
ping
