UBI: fix deadlock

We cannot call 'ubi_wl_get_peb()' with @ubi->buf_mutex locked,
because 'ubi_wl_get_peb()' may force erasure, which, in turn,
may call 'torture_peb()' which also locks the @ubi->buf_mutex
and deadlocks.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

1 files changed, 7 insertions, 7 deletions

diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
index d8966bae0e0b..2e4d6bf94582 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -504,12 +504,9 @@ static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
         if (!vid_hdr)
                 return -ENOMEM;
 
-        mutex_lock(&ubi->buf_mutex);
-
 retry:
         new_pnum = ubi_wl_get_peb(ubi, UBI_UNKNOWN);
         if (new_pnum < 0) {
-                mutex_unlock(&ubi->buf_mutex);
                 ubi_free_vid_hdr(ubi, vid_hdr);
                 return new_pnum;
         }
@@ -529,20 +526,23 @@ retry:
                 goto write_error;
 
         data_size = offset + len;
+        mutex_lock(&ubi->buf_mutex);
         memset(ubi->peb_buf1 + offset, 0xFF, len);
 
         /* Read everything before the area where the write failure happened */
         if (offset > 0) {
                 err = ubi_io_read_data(ubi, ubi->peb_buf1, pnum, 0, offset);
                 if (err && err != UBI_IO_BITFLIPS)
-                        goto out_put;
+                        goto out_unlock;
         }
 
         memcpy(ubi->peb_buf1 + offset, buf, len);
 
         err = ubi_io_write_data(ubi, ubi->peb_buf1, new_pnum, 0, data_size);
-        if (err)
+        if (err) {
+                mutex_unlock(&ubi->buf_mutex);
                 goto write_error;
+        }
 
         mutex_unlock(&ubi->buf_mutex);
         ubi_free_vid_hdr(ubi, vid_hdr);
@@ -553,8 +553,9 @@ retry:
         ubi_msg("data was successfully recovered");
         return 0;
 
-out_put:
+out_unlock:
         mutex_unlock(&ubi->buf_mutex);
+out_put:
         ubi_wl_put_peb(ubi, new_pnum, 1);
         ubi_free_vid_hdr(ubi, vid_hdr);
         return err;
@@ -567,7 +568,6 @@ write_error:
         ubi_warn("failed to write to PEB %d", new_pnum);
         ubi_wl_put_peb(ubi, new_pnum, 1);
         if (++tries > UBI_IO_RETRIES) {
-                mutex_unlock(&ubi->buf_mutex);
                 ubi_free_vid_hdr(ubi, vid_hdr);
                 return err;
         }