Patch "tracing: Fix kmemleak in tracing_map_array_free()" has been added to the 4.12-stable tree

This is a note to let you know that I've just added the patch titled

tracing: Fix kmemleak in tracing_map_array_free()

to the 4.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
tracing-fix-kmemleak-in-tracing_map_array_free.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Chunyu Hu <[email protected]>
Date: Mon, 14 Aug 2017 18:18:17 +0800
Subject: tracing: Fix kmemleak in tracing_map_array_free()

From: Chunyu Hu <[email protected]>

commit 475bb3c69ab05df2a6ecef6acc2393703d134180 upstream.

kmemleak reported the below leak when I was doing clear of the hist trigger. With this patch, the kmeamleak is gone.

unreferenced object 0xffff94322b63d760 (size 32):
comm "bash", pid 1522, jiffies 4403687962 (age 2442.311s) hex dump (first 32 bytes):

    00 01 00 00 04 00 00 00 08 00 00 00 ff 00 00 00  ................
    10 00 00 00 00 00 00 00 80 a8 7a f2 31 94 ff ff  ..........z.1...
  backtrace:
    [<ffffffff9e96c27a>] kmemleak_alloc+0x4a/0xa0
    [<ffffffff9e424cba>] kmem_cache_alloc_trace+0xca/0x1d0
    [<ffffffff9e377736>] tracing_map_array_alloc+0x26/0x140
    [<ffffffff9e261be0>] kretprobe_trampoline+0x0/0x50
    [<ffffffff9e38b935>] create_hist_data+0x535/0x750
    [<ffffffff9e38bd47>] event_hist_trigger_func+0x1f7/0x420
    [<ffffffff9e38893d>] event_trigger_write+0xfd/0x1a0
    [<ffffffff9e44dfc7>] __vfs_write+0x37/0x170
    [<ffffffff9e44f552>] vfs_write+0xb2/0x1b0
    [<ffffffff9e450b85>] SyS_write+0x55/0xc0
    [<ffffffff9e203857>] do_syscall_64+0x67/0x150
    [<ffffffff9e977ce7>] return_from_SYSCALL_64+0x0/0x6a
    [<ffffffffffffffff>] 0xffffffffffffffff
unreferenced object 0xffff9431f27aa880 (size 128):
  comm "bash", pid 1522, jiffies 4403687962 (age 2442.311s)
  hex dump (first 32 bytes):
    00 00 8c 2a 32 94 ff ff 00 f0 8b 2a 32 94 ff ff  ...*2......*2...
    00 e0 8b 2a 32 94 ff ff 00 d0 8b 2a 32 94 ff ff  ...*2......*2...
  backtrace:
    [<ffffffff9e96c27a>] kmemleak_alloc+0x4a/0xa0
    [<ffffffff9e425348>] __kmalloc+0xe8/0x220
    [<ffffffff9e3777c1>] tracing_map_array_alloc+0xb1/0x140
    [<ffffffff9e261be0>] kretprobe_trampoline+0x0/0x50
    [<ffffffff9e38b935>] create_hist_data+0x535/0x750
    [<ffffffff9e38bd47>] event_hist_trigger_func+0x1f7/0x420
    [<ffffffff9e38893d>] event_trigger_write+0xfd/0x1a0
    [<ffffffff9e44dfc7>] __vfs_write+0x37/0x170
    [<ffffffff9e44f552>] vfs_write+0xb2/0x1b0
    [<ffffffff9e450b85>] SyS_write+0x55/0xc0
    [<ffffffff9e203857>] do_syscall_64+0x67/0x150
    [<ffffffff9e977ce7>] return_from_SYSCALL_64+0x0/0x6a
    [<ffffffffffffffff>] 0xffffffffffffffff

---
 kernel/trace/tracing_map.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

@@ -221,16 +221,19 @@ void tracing_map_array_free(struct traci
 	if (!a)
 		return;
 
-	if (!a->pages) {
-		kfree(a);
-		return;
-	}
+	if (!a->pages)
+		goto free;
 
 	for (i = 0; i < a->n_pages; i++) {
 		if (!a->pages[i])
 			break;
 		free_page((unsigned long)a->pages[i]);
 	}
+
+	kfree(a->pages);
+
+ free:
+	kfree(a);
 }
 
 struct tracing_map_array *tracing_map_array_alloc(unsigned int n_elts,

Patches currently in stable-queue which might be from [email protected] are

queue-4.12/ring-buffer-have-ring_buffer_alloc_read_page-return-error-on-offline-cpu.patch queue-4.12/tracing-fix-freeing-of-filter-in-create_filter-when-set_str-is-false.patch queue-4.12/tracing-fix-kmemleak-in-tracing_map_array_free.patch