linux-kernel - [PATCH -next] jffs2: fix memory leak in jffs2_do_fill

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Date:   Tue, 12 Apr 2022 17:38:16 +0800
From:   Baokun Li <libaokun1@...wei.com>
To:     <richard@....at>, <dwmw2@...radead.org>,
        <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
CC:     <libaokun1@...wei.com>, <yukuai3@...wei.com>
Subject: [PATCH -next] jffs2: fix memory leak in jffs2_do_fill_super

If jffs2_iget() or d_make_root() in jffs2_do_fill_super() returns
an error, we can observe the following kmemleak report:

--------------------------------------------
unreferenced object 0xffff888105a65340 (size 64):
  comm "mount", pid 710, jiffies 4302851558 (age 58.239s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff859c45e5>] kmem_cache_alloc_trace+0x475/0x8a0
    [<ffffffff86160146>] jffs2_sum_init+0x96/0x1a0
    [<ffffffff86140e25>] jffs2_do_mount_fs+0x745/0x2120
    [<ffffffff86149fec>] jffs2_do_fill_super+0x35c/0x810
    [<ffffffff8614aae9>] jffs2_fill_super+0x2b9/0x3b0
    [...]
unreferenced object 0xffff8881bd7f0000 (size 65536):
  comm "mount", pid 710, jiffies 4302851558 (age 58.239s)
  hex dump (first 32 bytes):
    bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb  ................
    bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb  ................
  backtrace:
    [<ffffffff858579ba>] kmalloc_order+0xda/0x110
    [<ffffffff85857a11>] kmalloc_order_trace+0x21/0x130
    [<ffffffff859c2ed1>] __kmalloc+0x711/0x8a0
    [<ffffffff86160189>] jffs2_sum_init+0xd9/0x1a0
    [<ffffffff86140e25>] jffs2_do_mount_fs+0x745/0x2120
    [<ffffffff86149fec>] jffs2_do_fill_super+0x35c/0x810
    [<ffffffff8614aae9>] jffs2_fill_super+0x2b9/0x3b0
    [...]
--------------------------------------------

This is because the resources allocated in jffs2_sum_init() are not
released. Call jffs2_sum_exit() to release these resources to solve
the problem.

Fixes: e631ddba5887 ("[JFFS2] Add erase block summary support (mount time improvement)")
Signed-off-by: Baokun Li <libaokun1@...wei.com>
---
 fs/jffs2/fs.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c
index 71f03a5d36ed..f83a468b6488 100644
--- a/fs/jffs2/fs.c
+++ b/fs/jffs2/fs.c
@@ -604,6 +604,7 @@ int jffs2_do_fill_super(struct super_block *sb, struct fs_context *fc)
 	jffs2_free_raw_node_refs(c);
 	kvfree(c->blocks);
 	jffs2_clear_xattr_subsystem(c);
+	jffs2_sum_exit(c);
  out_inohash:
 	kfree(c->inocache_list);
  out_wbuf:
-- 
2.31.1