Re: [PATCH v2] locking/hung_task: Show all hung tasks before panic

2018-04-09 Thread Dmitry Vyukov
On Mon, Apr 9, 2018 at 1:13 PM, Tetsuo Handa wrote: >> > It will be nice if syzbot testing is done with kdump configured, and the >> > result of automated scripting on vmcore (such as "foreach bt -s -l") is >> > available. >> >> kdump's popped up several times already >> (https://github.com/google

Re: [PATCH v2] locking/hung_task: Show all hung tasks before panic

2018-04-09 Thread Tetsuo Handa
Dmitry Vyukov wrote: > On Sat, Apr 7, 2018 at 6:24 PM, Tetsuo Handa > wrote: > > Dmitry Vyukov wrote: > >> On Sat, Apr 7, 2018 at 5:39 PM, Peter Zijlstra > >> wrote: > >> > On Sat, Apr 07, 2018 at 09:31:19PM +0900, Tetsuo Handa wrote: > >> >> are for replacing debug_show_all_locks() in check_hun

Re: [PATCH v2] locking/hung_task: Show all hung tasks before panic

2018-04-09 Thread Dmitry Vyukov
On Sat, Apr 7, 2018 at 6:24 PM, Tetsuo Handa wrote: > Dmitry Vyukov wrote: >> On Sat, Apr 7, 2018 at 5:39 PM, Peter Zijlstra wrote: >> > On Sat, Apr 07, 2018 at 09:31:19PM +0900, Tetsuo Handa wrote: >> >> are for replacing debug_show_all_locks() in check_hung_task() for cases >> >> like >> >> ht

Re: [PATCH v2] locking/hung_task: Show all hung tasks before panic

2018-04-07 Thread Tetsuo Handa
Dmitry Vyukov wrote: > On Sat, Apr 7, 2018 at 5:39 PM, Peter Zijlstra wrote: > > On Sat, Apr 07, 2018 at 09:31:19PM +0900, Tetsuo Handa wrote: > >> are for replacing debug_show_all_locks() in check_hung_task() for cases > >> like > >> https://syzkaller.appspot.com/bug?id=26aa22915f5e3b7ca2cfca76a

Re: [PATCH v2] locking/hung_task: Show all hung tasks before panic

2018-04-07 Thread Dmitry Vyukov
On Sat, Apr 7, 2018 at 5:39 PM, Peter Zijlstra wrote: > On Sat, Apr 07, 2018 at 09:31:19PM +0900, Tetsuo Handa wrote: >> are for replacing debug_show_all_locks() in check_hung_task() for cases like >> https://syzkaller.appspot.com/bug?id=26aa22915f5e3b7ca2cfca76a939f12c25d624db >> because we are i

Re: [PATCH v2] locking/hung_task: Show all hung tasks before panic

2018-04-07 Thread Peter Zijlstra
On Sat, Apr 07, 2018 at 09:31:19PM +0900, Tetsuo Handa wrote: > are for replacing debug_show_all_locks() in check_hung_task() for cases like > https://syzkaller.appspot.com/bug?id=26aa22915f5e3b7ca2cfca76a939f12c25d624db > because we are interested in only threads holding locks. > > SysRq-t is too

Re: [PATCH v2] locking/hung_task: Show all hung tasks before panic

2018-04-07 Thread Tetsuo Handa
Hello. Can we add lockdep functions which print trace of threads with locks held? For example, void debug_show_map_users(struct lockdep_map *map) { struct task_struct *g, *p; struct held_lock *hlock; int i, depth; rcu_read_lock(); for_each_process_thread(

[PATCH v2] locking/hung_task: Show all hung tasks before panic

2018-04-04 Thread Tetsuo Handa
When we get a hung task it can often be valuable to see _all_ the hung tasks on the system before calling panic(). Quoting from https://syzkaller.appspot.com/text?tag=CrashReport&id=5316056503549952 INFO: task syz-executor0:6540 blocked for more than 120 s