On Fri, 2018-04-13 at 12:21 -0400, Josef Bacik wrote:
On Fri, Apr 13, 2018 at 04:16:18PM +0000, Bart Van Assche wrote:
On Fri, 2018-04-13 at 12:03 -0400, Josef Bacik wrote:
This fixes a use after free bug, we need to do the del_gendisk after we cleanup the queue on the device.
Hello Josef,
Which use-after-free bug does this patch fix? Are you aware that most block drivers call blk_cleanup_queue() before calling del_gendisk()? Why do you think that the nbd driver should use the opposite order?
I'm confused, that's what this patch does. Before I had del_gendisk() first and then the blk_cleanup_queue(), which was bugging out when I was testing stuff with a null pointer deref whenever I rmmod'ed the nbd. Swapping it to the way everybody else did it fixed the problem. Thanks,
Hello Josef,
Oops, I swapped "blk_cleanup_queue()" and "del_gendisk()" in my e-mail.
Can you share the call stack of the NULL pointer deref and also the translation of the crash address into a source code line?
Thanks,
Bart.