[BUG] net: brocade: bna: Possible concurrency use-after-free bugs

[Jia-Ju Bai]

In drivers/net/ethernet/brocade/bna/bnad_debugfs.c, the functions 
bnad_debugfs_read_regrd() and bnad_debugfs_write_regrd() may be 
concurrently executed.

bnad_debugfs_read_regrd()
  line 293: if (!bnad->regdata)
  line 297: simple_read_from_buffer(..., bnad->regdata, ...)
  line 300: kfree(bnad->regdata)

bnad_debugfs_write_regrd()
  line 335: kfree(bnad->regdata)
  line 338: kfree(bnad->regdata)
  line 357: regbuf =  (u32 *)bnad->regdata

All these accesses to bnad->regdata are not protected by any lock.
Thus, possible concurrency use-after-free bugs may occur.

A possible fixing way is to use a lock to protect these accesses.
I am not sure about this way, so I only report the bugs.


Best wishes,
Jia-Ju Bai