From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <526FF2BD.8030808@gmx.de> Date: Tue, 29 Oct 2013 18:39:09 +0100 From: =?UTF-8?B?VG9yYWxmIEbDtnJzdGVy?= MIME-Version: 1.0 References: <526696BF.6050909@gmx.de> <5266A698.10400@gmx.de> <5266B60A.1000005@nod.at> In-Reply-To: <5266B60A.1000005@nod.at> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Sender: linux-kernel-owner@vger.kernel.org Subject: Re: [uml-devel] fuzz tested 32 bit user mode linux image hangs at in hostfs To: Richard Weinberger Cc: Richard Weinberger , Linux Kernel , linux-fsdevel , "linux-mm@kvack.org" , UML devel List-ID: On 10/22/2013 07:29 PM, Richard Weinberger wrote: > Am 22.10.2013 18:23, schrieb Toralf F=C3=B6rster: >> On 10/22/2013 06:12 PM, Richard Weinberger wrote: >>> On Tue, Oct 22, 2013 at 5:16 PM, Toralf F=C3=B6rster wrote: >>>> >>>> When I fuzz testing a 32 bit UML at a 32 bit host (guest 3.12.-rc6= -x, host 3.11.6) with trinity >>>> and use hostfs for the victom files for trinity. then trintiy ofte= n hangs while trying to finish. >>>> >>>> At the host I do have 1 process eating 100% CPU power of 1 core. A= back trace of thet linux process at the hosts gives : >>>> >>>> tfoerste@n22 ~ $ sudo gdb /usr/local/bin/linux-v3.12-rc6-57-g69c88= dc 16749 -n -batch -ex bt >>>> radix_tree_next_chunk (root=3D0x21, iter=3D0x47647c60, flags=3D12)= at lib/radix-tree.c:769 >>>> 769 while (++offset < RADIX_TR= EE_MAP_SIZE) { >>>> #0 radix_tree_next_chunk (root=3D0x21, iter=3D0x47647c60, flags=3D= 12) at lib/radix-tree.c:769 >>>> #1 0x080cc13e in find_get_pages (mapping=3D0x483ed240, start=3D0,= nr_pages=3D14, pages=3D0xc) at mm/filemap.c:844 >>>> #2 0x080d5caa in pagevec_lookup (pvec=3D0x47647cc4, mapping=3D0x2= 1, start=3D33, nr_pages=3D33) at mm/swap.c:914 >>>> #3 0x080d609a in truncate_inode_pages_range (mapping=3D0x483ed240= , lstart=3D0, lend=3D-1) at mm/truncate.c:241 >>>> #4 0x080d643f in truncate_inode_pages (mapping=3D0x21, lstart=3D5= 1539607585) at mm/truncate.c:358 >>>> #5 0x08260838 in hostfs_evict_inode (inode=3D0x483ed188) at fs/ho= stfs/hostfs_kern.c:242 >>>> #6 0x0811a8cf in evict (inode=3D0x483ed188) at fs/inode.c:549 >>>> #7 0x0811b2ad in iput_final (inode=3D) at fs/inode= =2Ec:1391 >>>> #8 iput (inode=3D0x483ed188) at fs/inode.c:1409 >>>> #9 0x08117648 in dentry_iput (dentry=3D) at fs/dca= che.c:331 >>>> #10 d_kill (dentry=3D0x47d6d580, parent=3D0x47d95d10) at fs/dcache= =2Ec:477 >>>> #11 0x08118068 in dentry_kill (dentry=3D, unlock_on= _failure=3D) at fs/dcache.c:586 >>>> #12 dput (dentry=3D0x47d6d580) at fs/dcache.c:641 >>>> #13 0x08104903 in __fput (file=3D0x47471840) at fs/file_table.c:26= 4 >>>> #14 0x0810496b in ____fput (work=3D0x47471840) at fs/file_table.c:= 282 >>>> #15 0x08094496 in task_work_run () at kernel/task_work.c:123 >>>> #16 0x0807efd2 in exit_task_work (task=3D) at inclu= de/linux/task_work.h:21 >>>> #17 do_exit (code=3D1196535808) at kernel/exit.c:787 >>>> #18 0x0807f5dd in do_group_exit (exit_code=3D0) at kernel/exit.c:9= 20 >>>> #19 0x0807f649 in SYSC_exit_group (error_code=3D) a= t kernel/exit.c:931 >>>> #20 SyS_exit_group (error_code=3D0) at kernel/exit.c:929 >>>> #21 0x08062984 in handle_syscall (r=3D0x4763b1d4) at arch/um/kerne= l/skas/syscall.c:35 >>>> #22 0x08074fb5 in handle_trap (local_using_sysemu=3D, regs=3D, pid=3D) at arch/um/os-Linux/s= kas/process.c:198 >>>> #23 userspace (regs=3D0x4763b1d4) at arch/um/os-Linux/skas/process= =2Ec:431 >>>> #24 0x0805f750 in fork_handler () at arch/um/kernel/process.c:160 >>>> #25 0x00000000 in ?? () >>>> >>> >>> That trace is identical to the one you reported yesterday. >>> But this time no nfs is in the game, right? >>> >> >> Right - I could narrow down it in the meanwhile to hostfs only. Firs= t I >> argued if NFS sometimes might force the issue to happen later but in= the >> mean while I don't think so. >=20 > It looks like we never find a way out of the while(1) in > radix_tree_next_chunk(). >=20 > Thanks, > //richard >=20 But today I found a proof that it is not only fs/hostfs specific : tfoerste@n22 ~ $ sudo gdb /home/tfoerste/devel/linux/linux 22692 -n -ba= tch -ex bt 0x08298fcc in radix_tree_next_chunk (root=3D0x25, iter=3D0x3ba6fc4c, fl= ags=3D6) at lib/radix-tree.c:770 770 if (node->slots[offset]= ) #0 0x08298fcc in radix_tree_next_chunk (root=3D0x25, iter=3D0x3ba6fc4c= , flags=3D6) at lib/radix-tree.c:770 #1 0x080cc20e in find_get_pages (mapping=3D0x3b0d61dc, start=3D0, nr_p= ages=3D14, pages=3D0x6) at mm/filemap.c:844 #2 0x080d5d7a in pagevec_lookup (pvec=3D0x3ba6fcb0, mapping=3D0x25, st= art=3D37, nr_pages=3D37) at mm/swap.c:914 #3 0x080d616a in truncate_inode_pages_range (mapping=3D0x3b0d61dc, lst= art=3D0, lend=3D-1) at mm/truncate.c:241 #4 0x080d650f in truncate_inode_pages (mapping=3D0x25, lstart=3D257698= 03813) at mm/truncate.c:358 #5 0x08205b08 in nfs4_evict_inode (inode=3D0x3b0d6124) at fs/nfs/nfs4s= uper.c:101 #6 0x0811a99f in evict (inode=3D0x3b0d6124) at fs/inode.c:549 #7 0x0811b37d in iput_final (inode=3D) at fs/inode.c:13= 91 #8 iput (inode=3D0x3b0d6124) at fs/inode.c:1409 #9 0x081d6014 in nfs_dentry_iput (dentry=3D0x6, inode=3D0x3b0d6124) at= fs/nfs/dir.c:1255 #10 0x08117705 in dentry_iput (dentry=3D) at fs/dcache.c= :329 #11 d_kill (dentry=3D0x4508a000, parent=3D0x47adf790) at fs/dcache.c:47= 7 #12 0x08118138 in dentry_kill (dentry=3D, unlock_on_fail= ure=3D) at fs/dcache.c:586 #13 dput (dentry=3D0x4508a000) at fs/dcache.c:641 #14 0x081049d3 in __fput (file=3D0x3baf3000) at fs/file_table.c:264 #15 0x08104a3b in ____fput (work=3D0x3baf3000) at fs/file_table.c:282 #16 0x08094496 in task_work_run () at kernel/task_work.c:123 #17 0x0807efd2 in exit_task_work (task=3D) at include/li= nux/task_work.h:21 #18 do_exit (code=3D1167823872) at kernel/exit.c:787 #19 0x0807f5dd in do_group_exit (exit_code=3D0) at kernel/exit.c:920 #20 0x0807f649 in SYSC_exit_group (error_code=3D) at ker= nel/exit.c:931 #21 SyS_exit_group (error_code=3D0) at kernel/exit.c:929 #22 0x08062984 in handle_syscall (r=3D0x459741d4) at arch/um/kernel/ska= s/syscall.c:35 #23 0x08074fb5 in handle_trap (local_using_sysemu=3D, re= gs=3D, pid=3D) at arch/um/os-Linux/skas/p= rocess.c:198 #24 userspace (regs=3D0x459741d4) at arch/um/os-Linux/skas/process.c:43= 1 #25 0x0805f750 in fork_handler () at arch/um/kernel/process.c:160 #26 0x00000000 in ?? () But it happened rarely and I did not found a scenario to easily reprodu= ce it till now. --=20 MfG/Sincerely Toralf F=C3=B6rster pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel"= in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/