On Thu, Nov 20, 2014 at 8:01 PM, Toralf Förster <toralf.foers...@gmx.de> wrote: > A recent question at trinity's mailing list > (http://news.gmane.org/gmane.comp.security.fuzzing.trinity) points probably > to a hostfs issue - therefore I'd like to forward the answer f Dave Jones > here. > > ANd /me wonders how to use ftrace to further dig into this issue ?
UML has no ftrace support. But Daniel is working on it. > > > > -------- Forwarded Message -------- > Subject: Re: trinity doesn't exit after its finished > Date: Thu, 20 Nov 2014 13:21:54 -0500 > From: Dave Jones <da...@redhat.com> > To: Toralf Förster <toralf.foers...@gmx.de> > CC: trin...@vger.kernel.org > > On Thu, Nov 20, 2014 at 07:08:15PM +0100, Toralf Förster wrote: > > With latest git tree of trinity at a user mode linux image it stays here > forever: > > [child0:5249] <timed out> > > [main] Bailing main loop because Completed maximum number of operations.. > > [watchdog] [5096] Watchdog exiting because Completed maximum number of > operations.. > > So that [main] line is the last line in main_loop() > On return, we do this.. > > 159 main_loop(); > 160 > 161 shm->mainpid = 0; > 162 _exit(EXIT_SUCCESS); > > and yet.. > > > The proces list shows: > > > > $ ps fx -eo pid,start_time,command | grep -e trinity -e sleep | grep -v > grep > > 4878 18:30 | \_ bash -c logger "2#-1, M=/mnt/hostfs"; cd ~; sudo > su -c 'if [[ -d ./t3 ]]; then sudo chmod -R a+rwx ./t3; sudo rm -rf ./t3; > fi'; mkdir ./t3 && cd ./t3 || exit; if [[ -n /mnt/hostfs ]]; then if [[ -d > /mnt/hostfs/victims/v1 ]]; then sudo chmod -R a+rwx /mnt/hostfs/victims/v1; > sudo rm -rf /mnt/hostfs/victims/v1 || exit; fi; mkdir -p > /mnt/hostfs/victims/v1/v2; for i in $(seq -w 0 99); do touch > /mnt/hostfs/victims/v1/v2/f$i; mkdir /mnt/hostfs/victims/v1/v2/d$i; done; fi; > MALLOC_CHECK_=2 trinity -C 2 -N 25000 -q -V /mnt/hostfs/victims/v1/v2 > > 5095 18:30 | \_ trinity -C 2 -N 25000 -q -V > /mnt/hostfs/victims/v1/v2 > > 5096 18:30 | \_ [trinity-watchdo] <defunct> > > 5097 18:30 | \_ [trinity-main] > > Somehow it's still around. > > > Here are the stacks: > > > > $ sudo cat /proc/5097/stack > > > > [<0805f8b4>] __switch_to+0x44/0x70 > > [<0850b194>] __schedule+0x2f4/0x3a0 > > [<08097b8a>] __cond_resched+0x1a/0x30 > > [<0850b371>] _cond_resched+0x31/0x50 > > [<080dbbb2>] truncate_inode_pages_range+0x192/0x650 > > [<080dc102>] truncate_inode_pages_final+0x52/0x60 > > [<08275f18>] hostfs_evict_inode+0x18/0x40 > > [<08126e8d>] evict+0xdd/0x1b0 > > [<08127b0d>] iput+0x16d/0x180 > > [<08123538>] __dentry_kill+0x138/0x200 > > [<08123f66>] dput+0x156/0x180 > > [<0810fa15>] __fput+0x175/0x190 > > [<0810fa6b>] ____fput+0xb/0x10 > > [<08092956>] task_work_run+0x76/0x90 > > [<0807e92d>] do_exit+0x32d/0x940 > > [<0807f022>] do_group_exit+0xa2/0xf0 > > [<0807f087>] SyS_exit_group+0x17/0x20 > > [<08062980>] handle_syscall+0x60/0x80 > > [<080746fc>] userspace+0x46c/0x5e0 > > [<0805f720>] fork_handler+0x60/0x70 > > [<ffffffff>] 0xffffffff > > This is the interesting part. The process is about to exit, > but hostfs is doing.. something. It might just be taking a really > long time, or it might be stuck. If it happens again, you might > be able to use ftrace to figure out if hostfs is actually making > forward progress or not. > > Perhaps the UML folks have some ideas. > > > Maybe it helps you to improve trinity, if not, ignore this mail > > ;-) > > afaics, there's nothing here that trinity can do, once we've > called _exit(), we're done. Anything that happens afterwards is > the kernels fault :) > > Dave > > > > > > ------------------------------------------------------------------------------ > Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server > from Actuate! Instantly Supercharge Your Business Reports and Dashboards > with Interactivity, Sharing, Native Excel Exports, App Integration & more > Get technology previously reserved for billion-dollar corporations, FREE > http://pubads.g.doubleclick.net/gampad/clk?id=157005751&iu=/4140/ostg.clktrk > _______________________________________________ > User-mode-linux-devel mailing list > User-mode-linux-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel -- Thanks, //richard ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751&iu=/4140/ostg.clktrk _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
