diff options
| author | Shu Wang <shuwang@redhat.com> | 2017-09-12 10:14:54 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-10-12 11:51:24 +0200 |
| commit | a3ec104976f799808c2c1d8b32005c67b0037adb (patch) | |
| tree | cfc67a5b3b4646e805f1d7884beaf4d4595bbcc6 /kernel/trace | |
| parent | 3ff8bc813b1301ee1395b4629b5136559e3fc6ba (diff) | |
ftrace: Fix kmemleak in unregister_ftrace_graph
commit 2b0b8499ae75df91455bbeb7491d45affc384fb0 upstream.
The trampoline allocated by function tracer was overwriten by function_graph
tracer, and caused a memory leak. The save_global_trampoline should have
saved the previous trampoline in register_ftrace_graph() and restored it in
unregister_ftrace_graph(). But as it is implemented, save_global_trampoline was
only used in unregister_ftrace_graph as default value 0, and it overwrote the
previous trampoline's value. Causing the previous allocated trampoline to be
lost.
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
[
Looking further into this, I found that this was left over from when the
function and function graph tracers shared the same ftrace_ops. But in
commit 5f151b2401 ("ftrace: Fix function_profiler and function tracer
together"), the two were separated, and the save_global_trampoline no
longer was necessary (and it may have been broken back then too).
-- Steven Rostedt
]
Link: http://lkml.kernel.org/r/20170912021454.5976-1-shuwang@redhat.com
Fixes: 5f151b2401 ("ftrace: Fix function_profiler and function tracer together")
Signed-off-by: Shu Wang <shuwang@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/ftrace.c | 14 |
1 files changed, 0 insertions, 14 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 53ed8ae5de1c..5b8d7189e147 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -4381,9 +4381,6 @@ static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata; static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata; static int ftrace_set_func(unsigned long *array, int *idx, int size, 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); @@ -5981,17 +5978,6 @@ 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); } |