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From:   Richard Weinberger <richard.weinberger@gmail.com>
Date:   Fri, 7 Feb 2020 16:54:03 +0100
Message-ID: <CAFLxGvw-q3N98RhbtWCE5mGGv6qwrJBDTMTs_yMe9QDY6U4TAQ@mail.gmail.com>
Subject: Re: [PATCH] ubi: fix memory leak from ubi->fm_anchor
To:     Quanyang Wang <quanyang.wang@windriver.com>
Cc:     Richard Weinberger <richard@nod.at>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        linux-mtd@lists.infradead.org, LKML <linux-kernel@vger.kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>
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On Mon, Feb 3, 2020 at 10:14 AM Quanyang Wang
<quanyang.wang@windriver.com> wrote:
>
> Ping?
>
> On 1/14/20 5:33 PM, quanyang.wang@windriver.com wrote:
> > From: Quanyang Wang <quanyang.wang@windriver.com>
> >
> > Some ubi_wl_entry are allocated in erase_aeb() and one of them is
> > assigned to ubi->fm_anchor in __erase_worker(). And it should be freed
> > like others which are freed in tree_destroy(). Otherwise, it will
> > cause a memory leak:
> >
> > unreferenced object 0xbc094318 (size 24):
> >    comm "ubiattach", pid 491, jiffies 4294954015 (age 420.110s)
> >    hex dump (first 24 bytes):
> >      30 43 09 bc 00 00 00 00 00 00 00 00 01 00 00 00  0C..............
> >      02 00 00 00 04 00 00 00                          ........
> >    backtrace:
> >      [<6c2d5089>] erase_aeb+0x28/0xc8
> >      [<a1c68fb1>] ubi_wl_init+0x1d8/0x4a8
> >      [<d4f408f8>] ubi_attach+0xffc/0x10d0
> >      [<add3b5d8>] ubi_attach_mtd_dev+0x5b4/0x9fc
> >      [<d375a11c>] ctrl_cdev_ioctl+0xb8/0x1d8
> >      [<72b250f2>] vfs_ioctl+0x28/0x3c
> >      [<b80095d7>] do_vfs_ioctl+0xb0/0x798
> >      [<bf9ef69e>] ksys_ioctl+0x58/0x74
> >      [<5355bdbe>] ret_fast_syscall+0x0/0x54
> >      [<90c6c3ca>] 0x7eadf854
> >
> > Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>
> > ---
> >   drivers/mtd/ubi/wl.c | 2 ++
> >   1 file changed, 2 insertions(+)

Good catch!
Fixes: f9c34bb52997 ("ubi: Fix producing anchor PEBs")

---
Thanks,
//richard