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

ping ?

On 2018/10/20 20:08, Hou Tao 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@vger.kernel.org Fixes: 0029da3bf430 ("JFFS2: add UBI support") Signed-off-by: Hou Tao houtao1@huawei.com

---

fs/jffs2/wbuf.c | 7 +++++++ 1 file changed, 7 insertions(+)

diff --git a/fs/jffs2/wbuf.c b/fs/jffs2/wbuf.c index c6821a509481..3de45f4559d1 100644 --- a/fs/jffs2/wbuf.c +++ b/fs/jffs2/wbuf.c @@ -234,6 +234,13 @@ static int jffs2_verify_write(struct jffs2_sb_info *c, unsigned char *buf, size_t retlen; char *eccstr;

• /*

• * MTD emulated by UBI volume doesn't allocate wbuf_verify,
  

• * because it can do the verification itself.
  

• */
  

• if (!c->wbuf_verify)

• return 0;
  

• ret = mtd_read(c->mtd, ofs, c->wbuf_pagesize, &retlen, c->wbuf_verify); if (ret && ret != -EUCLEAN && ret != -EBADMSG) { pr_warn("%s(): Read back of page at %08x failed: %d\n",