Return-Path: linux-nfs-owner@vger.kernel.org Received: from top.free-electrons.com ([176.31.233.9]:37208 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751165AbaA3PQ4 (ORCPT ); Thu, 30 Jan 2014 10:16:56 -0500 Date: Thu, 30 Jan 2014 12:17:04 -0300 From: Ezequiel Garcia To: Russell King - ARM Linux , Trond Myklebust Cc: linux-nfs@vger.kernel.org, Christoph Hellwig , Al Viro , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Thomas Petazzoni , Gregory Clement Subject: Root NFS panicing on Linus' tip (Re: NFS client broken in Linus' tip) Message-ID: <20140130151703.GA20594@localhost> References: <20140130140834.GW15937@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 In-Reply-To: <20140130140834.GW15937@n2100.arm.linux.org.uk> Sender: linux-nfs-owner@vger.kernel.org List-ID: Hi Russell, Trond: On Thu, Jan 30, 2014 at 02:08:34PM +0000, Russell King - ARM Linux wrote: > I just booted Linus' tip (plus a few other patches to imx-drm and imx > code), and stumbled into this interesting scenario: > [..] > CONFIG_NFS_FS=y > CONFIG_NFS_V2=y > CONFIG_NFS_V3=y > CONFIG_NFS_V3_ACL=y Just came across another issue, but a bit more problematic, as my kernel (Linus' tip as well) panics, after mounting the rootfs: IP-Config: Complete: device=eth0, hwaddr=00:50:43:50:1c:15, ipaddr=192.168.0.159, mask=255.255.255.0, gw=192.168.0.1 host=develboard, domain=, nis-domain=(none) bootserver=192.168.0.45, rootserver=192.168.0.45, rootpath= VFS: Mounted root (nfs filesystem) on device 0:11. devtmpfs: mounted Freeing unused kernel memory: 136K (c0465000 - c0487000) Unable to handle kernel NULL pointer dereference at virtual address 00000000 pgd = c0004000 [00000000] *pgd=00000000 Internal error: Oops: 5 [#1] ARM Modules linked in: CPU: 0 PID: 1 Comm: swapper Tainted: G W 3.13.0-10094-g9b0cd30 #276 task: ed839a40 ti: ed83a000 task.ti: ed83a000 PC is at xattr_resolve_name+0x14/0x94 LR is at generic_getxattr+0x2c/0x64 pc : [] lr : [] psr: a0000113 sp : ed83be5c ip : ed83be74 fp : ed10ebc0 r10: ed83a000 r9 : ed43d980 r8 : ed81b800 r7 : c034dad8 r6 : 00000000 r5 : c03f3dcc r4 : ed43d980 r3 : 00000014 r2 : ed83be8c r1 : ed83be74 r0 : 00000000 Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel Control: 10c53c7d Table: 00004059 DAC: 00000015 Process swapper (pid: 1, stack limit = 0xed83a238) Stack: (0xed83be5c to 0xed83c000) be40: ed43d980 be60: 00000014 ed83be8c 00000000 00000000 c04bc22c c03f3dcc ed83bf14 ed43f340 be80: ed43d980 c01115cc 00000000 00000041 c04bba6c 00000000 00000000 002040d0 bea0: ed81bc00 ed10ebc0 ed81bc30 c01116f8 00000000 000004d0 ed8172d0 ed43d980 bec0: 45878fd4 00000007 bfe01007 ef7f8fc0 c04bba6c ed43d6d8 c04bba6c 00000101 bee0: 00000000 ed809fd0 ed809fc0 ed809f50 ed809f40 00000000 edb045d8 c0078bcc bf00: ed0e5dc0 edb045d8 00000000 bf000000 ed0e5dc0 00000000 00000000 00000000 bf20: 00000000 00000000 bf000000 ed10ebc0 ed0e5dc0 00000001 edb045d8 c04926d0 bf40: ed83a000 c0492758 ed10ebc0 c008fc54 00000001 ed0e5dc0 00000002 c0090cec bf60: c03ec85c ed0e5df4 00000000 ed839c00 c0487000 c04bcec0 c03e4f08 00000000 bf80: 00000000 00000000 00000000 00000000 00000000 c00086a8 00000000 c04bcec0 bfa0: c0344f5c c0345004 00000000 c000e398 00000000 00000000 00000000 00000000 bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 bfe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000 [] (xattr_resolve_name) from [<00000000>] ( (null)) Code: e1a06000 e5915000 e3550000 0a00001d (e5900000) ---[ end trace 15c15b4afa9eff90 ]--- swapper (1) used greatest stack depth: 5104 bytes left Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b Adding a little hack, and could produce a better strack trace. See the diff and the stack trace below: diff --git a/fs/xattr.c b/fs/xattr.c index 3377dff..bd2b173 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -740,6 +740,10 @@ xattr_resolve_name(const struct xattr_handler **handlers, const char **name) if (!*name) return NULL; + if(!handlers) { + dump_stack(); + panic("ouch"); + } for_each_xattr_handler(handlers, handler) { const char *n = strcmp_prefix(*name, handler->prefix); CPU: 0 PID: 1 Comm: swapper Tainted: G W 3.13.0-10094-g9b0cd30-dirty #279 [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [] (show_stack) from [] (xattr_resolve_name+0x9c/0xa8) [] (xattr_resolve_name) from [] (generic_getxattr+0x2c/0x64) [] (generic_getxattr) from [] (get_vfs_caps_from_disk+0x4c/0xf4) [] (get_vfs_caps_from_disk) from [] (cap_bprm_set_creds+0x84/0x408) [] (cap_bprm_set_creds) from [] (prepare_binprm+0x80/0x11c) [] (prepare_binprm) from [] (do_execve+0x33c/0x46c) [] (do_execve) from [] (try_to_run_init_process+0x1c/0x50) [] (try_to_run_init_process) from [] (kernel_init+0xa8/0x110) [] (kernel_init) from [] (ret_from_fork+0x14/0x3c) Kernel panic - not syncing: ouch FWIW, here's my piece of NFS config: CONFIG_NFS_FS=y CONFIG_NFS_V2=y CONFIG_NFS_V3=y # CONFIG_NFS_V3_ACL is not set # CONFIG_NFS_V4 is not set # CONFIG_NFS_SWAP is not set CONFIG_ROOT_NFS=y # CONFIG_NFSD is not set CONFIG_LOCKD=y CONFIG_LOCKD_V4=y CONFIG_NFS_COMMON=y CONFIG_SUNRPC=y > I think it's down to this: > > commit 013cdf1088d7235da9477a2375654921d9b9ba9f > Author: Christoph Hellwig > Date: Fri Dec 20 05:16:53 2013 -0800 > > nfs: use generic posix ACL infrastructure for v3 Posix ACLs > > This causes a small behaviour change in that we don't bother to set > ACLs on file creation if the mode bit can express the access permissions > fully, and thus behaving identical to local filesystems. > > Signed-off-by: Christoph Hellwig > Signed-off-by: Al Viro And also here, reverting the above seem to fix the panic. Ideas? -- Ezequiel García, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com