tracing: Fix memory leak in eprobe_register()
kmemleak report:
unreferenced object 0xffff900a70ec7ec0 (size 32):
comm "ftracetest", pid 2770, jiffies 4295042510 (age 311.464s)
hex dump (first 32 bytes):
c8 31 23 45 0a 90 ff ff 40 85 c7 6e 0a 90 ff ff .1#E....@..n....
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<000000009d3751fd>] kmem_cache_alloc_trace+0x2a2/0x440
[<0000000088b8124b>] eprobe_register+0x1e3/0x350
[<000000002a9a0517>] __ftrace_event_enable_disable+0x7c/0x240
[<0000000019109321>] event_enable_write+0x93/0xe0
[<000000007d85b320>] vfs_write+0xb9/0x260
[<00000000b94c5e41>] ksys_write+0x67/0xe0
[<000000005a08c81d>] __x64_sys_write+0x1a/0x20
[<00000000240bf576>] do_syscall_64+0x3b/0xc0
[<0000000043d5d9f6>] entry_SYSCALL_64_after_hwframe+0x44/0xae
unreferenced object 0xffff900a56bbf280 (size 128):
comm "ftracetest", pid 2770, jiffies 4295042510 (age 311.464s)
hex dump (first 32 bytes):
ff ff ff ff ff ff ff ff 00 00 00 00 01 00 00 00 ................
80 69 3b b2 ff ff ff ff 20 69 3b b2 ff ff ff ff .i;..... i;.....
backtrace:
[<000000009d3751fd>] kmem_cache_alloc_trace+0x2a2/0x440
[<00000000c4e90fad>] eprobe_register+0x1fc/0x350
[<000000002a9a0517>] __ftrace_event_enable_disable+0x7c/0x240
[<0000000019109321>] event_enable_write+0x93/0xe0
[<000000007d85b320>] vfs_write+0xb9/0x260
[<00000000b94c5e41>] ksys_write+0x67/0xe0
[<000000005a08c81d>] __x64_sys_write+0x1a/0x20
[<00000000240bf576>] do_syscall_64+0x3b/0xc0
[<0000000043d5d9f6>] entry_SYSCALL_64_after_hwframe+0x44/0xae
In new_eprobe_trigger(), allocated edata and trigger variables are
never freed.
To fix, free memory in disable_eprobe().
Link: https://lkml.kernel.org/r/20211008071802.GA2098@cosmos
Fixes: 7491e2c442781 ("tracing: Add a probe that attaches to trace events")
Signed-off-by: Vamshi K Sthambamkadi <vamshi.k.sthambamkadi@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 3044b76..570d081 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -632,6 +632,13 @@ static int disable_eprobe(struct trace_eprobe *ep,
trace_event_trigger_enable_disable(file, 0);
update_cond_flag(file);
+
+ /* Make sure nothing is using the edata or trigger */
+ tracepoint_synchronize_unregister();
+
+ kfree(edata);
+ kfree(trigger);
+
return 0;
}
