[PATCH AUTOSEL 5.6 66/79] ftrace: Fix memory leak caused by not freeing entry in unregister_ftrace_direct()

Sasha Levin
2020-04-30T14:08:13Z

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

[ Upstream commit 353da87921a5ec654e7e9024e083f099f1b33c97 ]

kmemleak reported the following:

unreferenced object 0xffff90d47127a920 (size 32):
comm "modprobe", pid 1766, jiffies 4294792031 (age 162.568s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 22 01 00 00 00 00 ad de ........".......
00 78 12 a7 ff ff ff ff 00 00 b6 c0 ff ff ff ff .x..............
backtrace:
[<00000000bb79e72e>] register_ftrace_direct+0xcb/0x3a0
[<00000000295e4f79>] do_one_initcall+0x72/0x340
[<00000000873ead18>] do_init_module+0x5a/0x220
[<00000000974d9de5>] load_module+0x2235/0x2550
[<0000000059c3d6ce>] __do_sys_finit_module+0xc0/0x120
[<000000005a8611b4>] do_syscall_64+0x60/0x230
[<00000000a0cdc49e>] entry_SYSCALL_64_after_hwframe+0x49/0xb3

The entry used to save the direct descriptor needs to be freed
when unregistering.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/trace/ftrace.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index fd81c7de77a70..63089c70adbb6 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5155,6 +5155,7 @@ int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
list_del_rcu(&direct->next);
synchronize_rcu_tasks();
kfree(direct);
+ kfree(entry);
ftrace_direct_func_count--;
}
}
--
2.20.1