tracing: Fix leaks of filter preds

commit 60705c89460fdc7227f2d153b68b3f34814738a4 upstream.

Special preds are created when folding a series of preds that
can be done in serial. These are allocated in an ops field of
the pred structure. But they were never freed, causing memory
leaks.

This was discovered using the kmemleak checker:

unreferenced object 0xffff8800797fd5e0 (size 32):
  comm "swapper/0", pid 1, jiffies 4294690605 (age 104.608s)
  hex dump (first 32 bytes):
    00 00 01 00 03 00 05 00 07 00 09 00 0b 00 0d 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff814b52af>] kmemleak_alloc+0x73/0x98
    [<ffffffff8111ff84>] kmemleak_alloc_recursive.constprop.42+0x16/0x18
    [<ffffffff81120e68>] __kmalloc+0xd7/0x125
    [<ffffffff810d47eb>] kcalloc.constprop.24+0x2d/0x2f
    [<ffffffff810d4896>] fold_pred_tree_cb+0xa9/0xf4
    [<ffffffff810d3781>] walk_pred_tree+0x47/0xcc
    [<ffffffff810d5030>] replace_preds.isra.20+0x6f8/0x72f
    [<ffffffff810d50b5>] create_filter+0x4e/0x8b
    [<ffffffff81b1c30d>] ftrace_test_event_filter+0x5a/0x155
    [<ffffffff8100028d>] do_one_initcall+0xa0/0x137
    [<ffffffff81afbedf>] kernel_init_freeable+0x14d/0x1dc
    [<ffffffff814b24b7>] kernel_init+0xe/0xdb
    [<ffffffff814d539c>] ret_from_fork+0x7c/0xb0
    [<ffffffffffffffff>] 0xffffffffffffffff

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index e5b0ca8b8d4ddc7a666a14c86bcf0a024046a7a8..5a8a53e67f8f59bb62e905bbe241d8d438f87ffa 100644 (file)
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -777,7 +777,11 @@ static int filter_set_pred(struct event_filter *filter,
 
 static void __free_preds(struct event_filter *filter)
 {
+       int i;
+
        if (filter->preds) {
+               for (i = 0; i < filter->n_preds; i++)
+                       kfree(filter->preds[i].ops);
                kfree(filter->preds);
                filter->preds = NULL;
        }