Re: NULL ptr deref in wq_worker_sleeping on 4.19

2019-08-07 Thread Thomas Gleixner
On Wed, 7 Aug 2019, Austin Kim wrote: Again: A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail? A: No. Q: Should I include quotations after my reply? http://daringfire

Re: NULL ptr deref in wq_worker_sleeping on 4.19

2019-08-07 Thread Austin Kim
Is it possible for you to generate kernel patch only with **kernel log** for 'use-after-free' case? With kernel log, we only have limited information, so it is hard to debug 'use-after-free' case with this signature. For this matter, kernel should be compiled with below config. CONFIG_SLUB_DEBUG=y

Re: NULL ptr deref in wq_worker_sleeping on 4.19

2019-08-07 Thread Thomas Gleixner
On Wed, 7 Aug 2019, Austin Kim wrote: A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail? A: No. Q: Should I include quotations after my reply? http://daringfireb

Re: NULL ptr deref in wq_worker_sleeping on 4.19

2019-08-07 Thread Austin Kim
I wonder what kinds of workqueue is used in case of this panic. If system workqueue(system_wq) is used for this case, it would be a help to replace it with high priority workqueue(system_highpri_wq). If panic disappers with high priority workqueue(system_highpri_wq), we would think about another s

Re: NULL ptr deref in wq_worker_sleeping on 4.19

2019-08-07 Thread Sebastian Andrzej Siewior
On 2019-07-19 09:53:52 [-0400], Sasha Levin wrote: > Hi folks, Hi, > We're seeing a rare panic on boot in wq_worker_sleeping() on boot in > 4.19 kernels. I wasn't able to reproduce this with 5.2, but I'm not sure > whether it's because the issue is fixed, or I was just unlucky. > > The panic look

NULL ptr deref in wq_worker_sleeping on 4.19

2019-07-19 Thread Sasha Levin
Hi folks, We're seeing a rare panic on boot in wq_worker_sleeping() on boot in 4.19 kernels. I wasn't able to reproduce this with 5.2, but I'm not sure whether it's because the issue is fixed, or I was just unlucky. The panic looks like this: [0.852791] BUG: unable to handle kernel NULL poi