Re: [PATCH] jffs2: ensure wbuf_verify is valid before using it.

[Richard Weinberger <richard.weinberger@xxxxxxxxx>]

On Sat, Oct 20, 2018 at 2:06 PM Hou Tao <houtao1@xxxxxxxxxx> wrote:
>
> Now MTD emulated by UBI volumn doesn't allocate wbuf_verify in
> jffs2_ubivol_setup(), because UBI can do the verifcation itself,
> so when CONFIG_JFFS2_FS_WBUF_VERIFY is enabled and a MTD device
> emulated by UBI volumn is used, a Oops will occur as show in the
> following trace:
>
>     general protection fault: 0000 [#1] SMP KASAN PTI
>     CPU: 6 PID: 404 Comm: kworker/6:1 Not tainted 4.19.0-rc8
>     Workqueue: events_long delayed_wbuf_sync
>     RIP: 0010:ubi_io_read+0x156/0x650
>     Call Trace:
>      ubi_eba_read_leb+0x57d/0xba0
>      ubi_leb_read+0xe5/0x1b0
>      gluebi_read+0x10c/0x1a0
>      mtd_read+0x112/0x340
>      jffs2_verify_write+0xef/0x440
>      __jffs2_flush_wbuf+0x3fa/0x3540
>      jffs2_flush_wbuf_gc+0x1b1/0x2e0
>      process_one_work+0x58b/0x11e0
>      worker_thread+0x8f/0xfe0
>      kthread+0x2ae/0x3a0
>      ret_from_fork+0x35/0x40
>
> Fix the problem by checking the validity of wbuf_verify before
> using it in jffs2_verify_write().
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 0029da3bf430 ("JFFS2: add UBI support")
> Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>

Reviewed-by: Richard Weinberger <richard@xxxxxx>

BTW: Are you actually using glubi? It is on my list of things I'd like
to kill. :-)

-- 
Thanks,
//richard

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