On Mon, Jun 14, 2021 at 9:34 PM Pavel Skripkin <paskripkin@xxxxxxxxx> wrote: > > On Mon, 14 Jun 2021 21:22:43 +0800 > Dongliang Mu <mudongliangabcd@xxxxxxxxx> wrote: > > > Dear kernel developers, > > > > I was trying to debug the crash - memory leak in hwsim_add_one [1] > > recently. However, I encountered a disgusting issue: my breakpoint and > > printk/pr_alert in the functions that will be surely executed do not > > work. The stack trace is in the following. I wrote this email to ask > > for some suggestions on how to debug such cases? > > > > Thanks very much. Looking forward to your reply. > > > > Hi, Dongliang! > > This bug is not similar to others on the dashboard. I spent some time > debugging it a week ago. The main problem here, that memory > allocation happens in the boot time: > > > [<ffffffff84359255>] kernel_init+0xc/0x1a7 init/main.c:1447 > Oh, nice catch. No wonder why my debugging does not work. :( > and reproducer simply tries to > free this data. You can use ftrace to look at it. Smth like this: > > $ echo 'hwsim_*' > $TRACE_DIR/set_ftrace_filter Thanks for your suggestion. Do you have any conclusions about this case? If you have found out the root cause and start writing patches, I will turn my focus to other cases. BTW, I only found another possible memory leak after some manual code review [1]. However, it is not the root cause for this crash. [1] https://lkml.org/lkml/2021/6/10/1297 > > would work. > > > With regards, > Pavel Skripkin