On 6/8/2018 5:17 PM, Ben Greear wrote:
I recalled an email from Michał leaving tieto so adding his alternate
email he provided back then.
Gr. AvS
On 06/07/2018 04:59 PM, Cong Wang wrote:
On Thu, Jun 7, 2018 at 4:48 PM, <greearb@xxxxxxxxxxxxxxx> wrote:
diff --git a/include/net/fq_impl.h b/include/net/fq_impl.h
index be7c0fa..cb911f0 100644
--- a/include/net/fq_impl.h
+++ b/include/net/fq_impl.h
@@ -78,7 +78,10 @@ static struct sk_buff *fq_tin_dequeue(struct fq *fq,
return NULL;
}
- flow = list_first_entry(head, struct fq_flow, flowchain);
+ flow = list_first_entry_or_null(head, struct fq_flow,
flowchain);
+
+ if (WARN_ON_ONCE(!flow))
+ return NULL;
This does not make sense either. list_first_entry_or_null()
returns NULL only when the list is empty, but we already check
list_empty() right before this code, and it is protected by fq->lock.
Hello Michal,
git blame shows you as the author of the fq_impl.h code.
I saw a crash when debugging funky ath10k firmware in a 4.16 + hacks
kernel. There was an apparent
mostly-null deref in the fq_tin_dequeue method. According to gdb, it
was within
1 line of the dereference of 'flow'.
My hack above is probably not that useful. Cong thinks maybe the
locking is bad.
If you get a chance, please review this thread and see if you have any
ideas for
a better fix (or better debugging code).
As always, if you would like me to generate you a buggy firmware that
will crash
in the tx path and cause all sorts of mayhem in the ath10k driver and
wifi stack,
I will be happy to do so.
https://www.mail-archive.com/netdev@xxxxxxxxxxxxxxx/msg239738.html
Thanks,
Ben
