On Mon, Jul 9, 2018 at 3:19 PM, Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> wrote: > Dmitry, do you know how/why syzbot is enabling debug messages? > > On 2018/07/09 16:38, Greg Kroah-Hartman wrote: >> On Mon, Jul 09, 2018 at 10:10:34AM +0900, Tetsuo Handa wrote: >>> >From 62ddef96020cb397dcbf4b8574f1859b32f983de Mon Sep 17 00:00:00 2001 >>> From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> >>> Date: Mon, 9 Jul 2018 09:54:01 +0900 >>> Subject: [PATCH] ANDROID: binder: Latelimit binder_debug(). >>> >>> syzbot is reporting hung tasks [1] [2]. This might be due to flooding of >>> printk() messages from binder subsystem, for NMI backtrace says the CPU >>> was busy doing printk() from binder subsystem. Since the kernel log buffer >>> is trivially spammed by debug messages, let's latelimit binder_debug(). >> >> How is the binder debug messages being turned on? They are not enabled >> by default, is syzbot enabling them? If so, then I don't know if this >> needs to be changed, as you want those debug messages if you ask for >> them, you shouldn't ratelimit them. >> >> thanks, >> >> greg k-h I know almost nothing about binder. How these debug messages are enabled? I don't see anything like CONFIG_BINDER_VERBOSE_DEBUG in the config: https://github.com/google/syzkaller/blob/master/dashboard/config/upstream-kasan.config Also no mentions of binder in sysctl/cmline. All binder maintainers are in CC already, perhaps they can shed some light on this. _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
