From: =?UTF-8?B?VG9yYWxmIEbDtnJzdGVy?= Subject: Re: [uml-devel] fuzz tested 32 bit user mode linux image hangs in radix_tree_next_chunk() Date: Wed, 30 Oct 2013 20:15:29 +0100 Message-ID: <52715AD1.7000703@gmx.de> References: <526696BF.6050909@gmx.de> <5266A698.10400@gmx.de> <5266B60A.1000005@nod.at> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: Richard Weinberger , Linux Kernel , linux-fsdevel , "linux-mm@kvack.org" , UML devel To: Richard Weinberger Return-path: In-Reply-To: <5266B60A.1000005@nod.at> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org 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 often = hangs while trying to finish. >>>> >>>> At the host I do have 1 process eating 100% CPU power of 1 core. A b= ack trace of thet linux process at the hosts gives : >>>> >>>> tfoerste@n22 ~ $ sudo gdb /usr/local/bin/linux-v3.12-rc6-57-g69c88dc= 16749 -n -batch -ex bt >>>> radix_tree_next_chunk (root=3D0x21, iter=3D0x47647c60, flags=3D12) a= t lib/radix-tree.c:769 >>>> 769 while (++offset < RADIX_TREE= _MAP_SIZE) { >>>> #0 radix_tree_next_chunk (root=3D0x21, iter=3D0x47647c60, flags=3D1= 2) at lib/radix-tree.c:769 >>>> #1 0x080cc13e in find_get_pages (mapping=3D0x483ed240, start=3D0, n= r_pages=3D14, pages=3D0xc) at mm/filemap.c:844 >>>> #2 0x080d5caa in pagevec_lookup (pvec=3D0x47647cc4, mapping=3D0x21,= 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=3D515= 39607585) at mm/truncate.c:358 >>>> #5 0x08260838 in hostfs_evict_inode (inode=3D0x483ed188) at fs/host= fs/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.c= :1391 >>>> #8 iput (inode=3D0x483ed188) at fs/inode.c:1409 >>>> #9 0x08117648 in dentry_iput (dentry=3D) at fs/dcach= e.c:331 >>>> #10 d_kill (dentry=3D0x47d6d580, parent=3D0x47d95d10) at fs/dcache.c= :477 >>>> #11 0x08118068 in dentry_kill (dentry=3D, unlock_on_f= ailure=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:264 >>>> #14 0x0810496b in ____fput (work=3D0x47471840) at fs/file_table.c:28= 2 >>>> #15 0x08094496 in task_work_run () at kernel/task_work.c:123 >>>> #16 0x0807efd2 in exit_task_work (task=3D) at include= /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:920 >>>> #19 0x0807f649 in SYSC_exit_group (error_code=3D) at = 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/kernel/= skas/syscall.c:35 >>>> #22 0x08074fb5 in handle_trap (local_using_sysemu=3D,= regs=3D, pid=3D) at arch/um/os-Linux/skas/= process.c:198 >>>> #23 userspace (regs=3D0x4763b1d4) at arch/um/os-Linux/skas/process.c= :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. First = I >> argued if NFS sometimes might force the issue to happen later but in t= he >> 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 FWIW here's a slightly different and much shorter gdb back trace=20 tfoerste@n22 ~/devel/linux $ sudo gdb /usr/local/bin/linux-v3.12-rc7 3105= -n -batch -ex bt 0x08298f16 in radix_tree_next_chunk (root=3D0x0, iter=3D0x46c2fcec, flags= =3D18) at lib/radix-tree.c:756 756 if ((flags & RADIX_TREE_ITER_TAGGED) ? #0 0x08298f16 in radix_tree_next_chunk (root=3D0x0, iter=3D0x46c2fcec, f= lags=3D18) at lib/radix-tree.c:756 #1 0x080cc20e in find_get_pages (mapping=3D0x26c35130, start=3D0, nr_pag= es=3D14, pages=3D0x12) at mm/filemap.c:844 #2 0x080d5d7a in pagevec_lookup (pvec=3D0x46c2fd50, mapping=3D0x0, start= =3D0, nr_pages=3D0) at mm/swap.c:914 #3 0x080d616a in truncate_inode_pages_range (mapping=3D0x26c35130, lstar= t=3D0, lend=3D-1) at mm/truncate.c:241 #4 0x080d650f in truncate_inode_pages (mapping=3D0x0, lstart=3D773094113= 28) at mm/truncate.c:358 #5 0x0818d7e2 in ext4_evict_inode (inode=3D0x26c35078) at fs/ext4/inode.= c:228 #6 0x0811a99f in evict (inode=3D0x26c35078) at fs/inode.c:549 #7 0x0811b37d in iput_final (inode=3D) at fs/inode.c:1391 #8 iput (inode=3D0x26c35078) at fs/inode.c:1409 #9 0x08111717 in do_unlinkat (dfd=3D5, pathname=3D0x80686c4 "_\b\205\322tJU\211\345\203\354\024\307D$\020") at fs/namei.= c:3730 #10 0x08111835 in SYSC_unlinkat (flag=3D, pathname=3D, dfd=3D) at fs/namei.c:3756 #11 SyS_unlinkat (dfd=3D5, pathname=3D134645444, flag=3D0) at fs/namei.c:= 3748 #12 0x08062984 in handle_syscall (r=3D0x48408dd4) at arch/um/kernel/skas/= syscall.c:35 #13 0x08074fb5 in handle_trap (local_using_sysemu=3D, regs= =3D, pid=3D) at arch/um/os-Linux/skas/proce= ss.c:198 #14 userspace (regs=3D0x48408dd4) at arch/um/os-Linux/skas/process.c:431 #15 0x0805f750 in fork_handler () at arch/um/kernel/process.c:160 #16 0x5a5a5a5a in ?? () > Thanks, > //richard >=20 --=20 MfG/Sincerely Toralf F=C3=B6rster pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org