Re: kern/53005: apache httpd can hang the system

[clare%csel.org@localhost]

The following reply was made to PR kern/53005; it has been noted by GNATS.

From: clare%csel.org@localhost
To: gnats-bugs%NetBSD.org@localhost
Cc: Manuel Bouyer <bouyer%antioche.eu.org@localhost>, kern-bug-people%netbsd.org@localhost,
 gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost
Subject: Re: kern/53005: apache httpd can hang the system
Date: Wed, 14 Feb 2018 00:41:30 +0900

 On Mon, 12 Feb 2018 19:20:01 +0000 (UTC)
 Manuel Bouyer <bouyer%antioche.eu.org@localhost> wrote:
 
 > From: Manuel Bouyer <bouyer%antioche.eu.org@localhost>
 > To: clare%csel.org@localhost
 > Cc: gnats-bugs%NetBSD.org@localhost, kern-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost,
 >         netbsd-bugs%netbsd.org@localhost
 > Subject: Re: kern/53005: apache httpd can hang the system
 > Date: Mon, 12 Feb 2018 20:18:06 +0100
 > 
 >  On Mon, Feb 12, 2018 at 03:40:38PM +0900, clare%csel.org@localhost wrote:
 >  > >  When it hangs, can you enter ddb and get a backtrace of the apache process ?
 >  > 
 >  > db{0}> bt
 >  > breakpoint() at netbsd:breakpoint+0x5
 >  > wskbd_translate() at netbsd:wskbd_translate+0xbb4
 >  > wskbd_input() at netbsd:wskbd_input+0x5b
 >  > pckbd_input() at netbsd:pckbd_input+0x6b
 >  > pckbcintr() at netbsd:pckbcintr+0x8d
 >  > intr_bloglock_wrapper() at netbsd:intr_biglock_wrapper+0x1d
 >  > Xintr_ioapic_edge4() at netbsd:Xintr_ioapic_edge4+0xf1
 >  > --- interrupt ---
 >  > exit_lwps() at netbsd:exit_lwps+0x58
 >  > exit1() at netbsd:exit1+0x68
 >  > sys_exit() at netbsd:sys_eit+0x3d
 >  > syscall() at netbsd:syscall+0x1d8
 >  > --- syscall (number 1) ---
 >  > 
 >  > db{0}> trace/t 50
 >  > trace: pid 80 lid 40 at 0xffff80002a503db0
 >  > ?() at ffffe4001fa3b5c0
 >  > lwp_exit_switchaway() at netbsd:lwp_exit_switchaway+0x1ac
 >  > Bad frame pointer: 0xffffe4001a1c8300
 >  
 >  Do you want to backtrace pid 50 (decimal) or 80 (decimal) ?
 >  if you want to trace pid 50, you have to use:
 >  trace/t 0t50
 >  (numbers are interpreted as hex by default).
 
 the PID was 80 as of showing ps command in ddb.
 i thounght 80 was shown in decimal.
 
 screenshot is here:
 https://www.csel.org/netbsd/pr/53005/ddb-2018-2-12.png
 
 
 >  Also it would be interesting to see which pid was interupted by entering ddb.
 >  I wonder if it's stuck looping in exit_lwps()
 
 I cannot reproduce the problem on the bare metal multiprocessor local
 machine, currently.
 
 when I enabled both LOCKDEBUG and DEBUG options, then problem was gone.
 
 when I enabled DEBUG and without LOCKDEBUG options, then problem was gone.
 
 when I enabled LOCKDEBUG and without DEBUG options, then problem was appeared,
 screenshots are in https://www.csel.org/netbsd/pr/53005/lockdebug/
 
 
 -- 
 Shinichi Doyashiki <clare%csel.org@localhost>