Re: Kernel OPS when using xattr

["Mkrtchyan, Tigran" <tigran.mkrtchyan@desy.de>]

Hi Trond,

I can list and read attributes, but still get
stack traces (and getdeviceinfo still broken)


[  111.887664] ------------[ cut here ]------------
[  111.887696] WARNING: CPU: 4 PID: 1313 at net/sunrpc/clnt.c:2478 call_decode+0x1a1/0x1f0 [sunrpc]
[  111.887697] Modules linked in: nfs_layout_flexfiles rpcsec_gss_krb5 auth_rpcgss nfsv4(E) dns_resolver nfs(E) lockd grace nfs_ssc fscache nf_conntrack_netbios_ns nf_conntrack_broadcast nft_ct nf_tables ebtable_nat ebtable_broute ip6table_nat ip6table_mangle ip6table_raw ip6table_security iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_mangle iptable_raw iptable_security ip_set nfnetlink ebtable_filter ebtables ip6table_filter ip6_tables sunrpc(E) snd_hda_codec_idt snd_hda_codec_generic ledtrig_audio nouveau i915 iwldvm mac80211 btrfs intel_rapl_msr snd_hda_codec_hdmi intel_rapl_common snd_hda_intel x86_pkg_temp_thermal uvcvideo snd_intel_dspcfg libarc4 snd_hda_codec coretemp kvm_intel videobuf2_vmalloc iwlwifi snd_hda_core videobuf2_memops videobuf2_v4l2 snd_hwdep snd_seq blake2b_generic videobuf2_common kvm at24 iTCO_wdt xor snd_seq_device videodev regmap_i2c dcdbas zstd_decompress ppdev iTCO_vendor_support wmi_bmof mxm_wmi snd_pcm cfg80211 dell_smm_hwmon ttm
[  111.887754]  zstd_compress i2c_algo_bit e1000e mc irqbypass snd_timer mei_me drm_kms_helper snd raid6_pq pcspkr i2c_i801 joydev ptp lpc_ich rfkill i2c_smbus mei soundcore pps_core mfd_core wmi parport_pc parport video dell_smo8800 drm sdhci_pci crct10dif_pclmul cqhci crc32_pclmul crc32c_intel sdhci ghash_clmulni_intel mmc_core firewire_ohci serio_raw firewire_core crc_itu_t fuse
[  111.887785] CPU: 4 PID: 1313 Comm: attr Tainted: G            E     5.10.0-rc6+ #60
[  111.887787] Hardware name: Dell Inc. Latitude E6520/0J4TFW, BIOS A06 07/11/2011
[  111.887803] RIP: 0010:call_decode+0x1a1/0x1f0 [sunrpc]
[  111.887805] Code: df 02 00 0f b7 85 dc 00 00 00 e9 cc fe ff ff 48 c7 45 20 90 d5 da a0 48 89 e6 48 89 ef e8 17 8c 01 00 89 45 04 e9 ed fe ff ff <0f> 0b e9 3d ff ff ff 65 8b 05 e1 5f 27 5f 89 c0 48 0f a3 05 87 09
[  111.887807] RSP: 0018:ffffc9000171b9f0 EFLAGS: 00010286
[  111.887809] RAX: 00000000fffffff0 RBX: ffff888103f11200 RCX: 0000000000000010
[  111.887810] RDX: 00000000fffffff0 RSI: 0000000000000048 RDI: ffff888103f11250
[  111.887811] RBP: ffff888101435500 R08: ffff888103f11330 R09: ffff888235b2c550
[  111.887812] R10: 0000000000000362 R11: 0000000000000327 R12: ffff888103f11250
[  111.887813] R13: ffff888101435530 R14: 0000000000000000 R15: ffff888101e76e18
[  111.887815] FS:  00007f4d48875740(0000) GS:ffff888235b00000(0000) knlGS:0000000000000000
[  111.887817] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  111.887818] CR2: 00007f4d48a48000 CR3: 000000011c72e002 CR4: 00000000000606e0
[  111.887819] Call Trace:
[  111.887829]  ? out_of_line_wait_on_bit+0x92/0xb0
[  111.887844]  ? rpc_decode_header+0x4e0/0x4e0 [sunrpc]
[  111.887863]  __rpc_execute+0x71/0x420 [sunrpc]
[  111.887885]  ? xprt_iter_default_rewind+0x10/0x10 [sunrpc]
[  111.887907]  ? xprt_iter_get_next+0x4a/0x60 [sunrpc]
[  111.887922]  rpc_run_task+0x14c/0x180 [sunrpc]
[  111.887940]  nfs4_do_call_sync+0x6e/0xb0 [nfsv4]
[  111.887961]  _nfs42_proc_getxattr+0xb7/0x170 [nfsv4]
[  111.887984]  ? xprt_iter_get_next+0x4a/0x60 [sunrpc]
[  111.888005]  nfs42_proc_getxattr+0x86/0xb0 [nfsv4]
[  111.888018]  nfs4_xattr_get_nfs4_user+0xc9/0xe0 [nfsv4]
[  111.888023]  vfs_getxattr+0x161/0x1a0
[  111.888026]  getxattr+0x14f/0x230
[  111.888028]  ? filename_lookup+0x123/0x1b0
[  111.888031]  ? _cond_resched+0x16/0x40
[  111.888034]  ? kmem_cache_alloc+0x3c4/0x4b0
[  111.888036]  ? getname_flags.part.0+0x45/0x1a0
[  111.888039]  path_getxattr+0x62/0xb0
[  111.888043]  do_syscall_64+0x33/0x40
[  111.888046]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  111.888048] RIP: 0033:0x7f4d4897762e
[  111.888050] Code: 48 8b 0d 4d 48 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 c0 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 1a 48 0c 00 f7 d8 64 89 01 48
[  111.888052] RSP: 002b:00007fff01750768 EFLAGS: 00000202 ORIG_RAX: 00000000000000c0
[  111.888054] RAX: ffffffffffffffda RBX: 00007fff017508d0 RCX: 00007f4d4897762e
[  111.888055] RDX: 0000000000000000 RSI: 00007fff017508d0 RDI: 00007fff0176243a
[  111.888056] RBP: 0000000000000000 R08: 00007fff017507b0 R09: 0000000000000000
[  111.888057] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000001
[  111.888058] R13: 00007fff017507b0 R14: 00007fff0176243a R15: 0000000000000000
[  111.888060] ---[ end trace fdd032a781f2160d ]---
[  111.889050] ------------[ cut here ]------------


Tigran.

----- Original Message -----
> From: "trondmy" <trondmy@hammerspace.com>
> To: "Tigran Mkrtchyan" <tigran.mkrtchyan@desy.de>
> Cc: "Frank van der Linden" <fllinden@amazon.com>, "linux-nfs" <linux-nfs@vger.kernel.org>
> Sent: Thursday, 3 December, 2020 18:13:26
> Subject: Re: Kernel OPS when using xattr

> On Thu, 2020-12-03 at 17:04 +0100, Mkrtchyan, Tigran wrote:
>> 
>> 
>> Hi Trond,
>> 
>> unfortunately the same result. Here the output of gdb, if it helps.
>> 
>> (gdb) list *0x00000000000252be
>> 0x252be is in _shift_data_right_pages (net/sunrpc/xdr.c:344).
>> 339                     if (*pgto != *pgfrom) {
>> 340                             vfrom = kmap_atomic(*pgfrom);
>> 341                             memcpy(vto + pgto_base, vfrom +
>> pgfrom_base, copy);
>> 342                             kunmap_atomic(vfrom);
>> 343                     } else
>> 344                             memmove(vto + pgto_base, vto +
>> pgfrom_base, copy);
>> 345                     flush_dcache_page(*pgto);
>> 346                     kunmap_atomic(vto);
>> 347
>> 348             } while ((len -= copy) != 0);
>> (gdb)
>> 
> 
> You probably need this one in addition to the first patch.
> 8<----------------------------------------------------
> From fec77469f373fbccb292c2d522f2ebee3b9011a8 Mon Sep 17 00:00:00 2001
> From: Trond Myklebust <trond.myklebust@hammerspace.com>
> Date: Thu, 3 Dec 2020 12:04:51 -0500
> Subject: [PATCH] NFSv4.2: Fix up the get/listxattr calls to
> rpc_prepare_reply_pages()
> 
> Ensure that both getxattr and listxattr page array are correctly
> aligned, and that getxattr correctly accounts for the page padding
> word.
> 
> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
> ---
> fs/nfs/nfs42xdr.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/nfs/nfs42xdr.c b/fs/nfs/nfs42xdr.c
> index 8432bd6b95f0..103978ff76c9 100644
> --- a/fs/nfs/nfs42xdr.c
> +++ b/fs/nfs/nfs42xdr.c
> @@ -191,7 +191,7 @@
> 
> #define encode_getxattr_maxsz   (op_encode_hdr_maxsz + 1 + \
> 				 nfs4_xattr_name_maxsz)
> -#define decode_getxattr_maxsz   (op_decode_hdr_maxsz + 1 + 1)
> +#define decode_getxattr_maxsz   (op_decode_hdr_maxsz + 1 +
> pagepad_maxsz)
> #define encode_setxattr_maxsz   (op_encode_hdr_maxsz + \
> 				 1 + nfs4_xattr_name_maxsz + 1)
> #define decode_setxattr_maxsz   (op_decode_hdr_maxsz +
> decode_change_info_maxsz)
> @@ -1476,17 +1476,18 @@ static void nfs4_xdr_enc_getxattr(struct
> rpc_rqst *req, struct xdr_stream *xdr,
> 	struct compound_hdr hdr = {
> 		.minorversion = nfs4_xdr_minorversion(&args-
>>seq_args),
> 	};
> +	uint32_t replen;
> 	size_t plen;
> 
> 	encode_compound_hdr(xdr, req, &hdr);
> 	encode_sequence(xdr, &args->seq_args, &hdr);
> 	encode_putfh(xdr, args->fh, &hdr);
> +	replen = hdr.replen + op_decode_hdr_maxsz + 1;
> 	encode_getxattr(xdr, args->xattr_name, &hdr);
> 
> 	plen = args->xattr_len ? args->xattr_len : XATTR_SIZE_MAX;
> 
> -	rpc_prepare_reply_pages(req, args->xattr_pages, 0, plen,
> -	    hdr.replen);
> +	rpc_prepare_reply_pages(req, args->xattr_pages, 0, plen,
> replen);
> 	req->rq_rcv_buf.flags |= XDRBUF_SPARSE_PAGES;
> 
> 	encode_nops(&hdr);
> @@ -1520,14 +1521,15 @@ static void nfs4_xdr_enc_listxattrs(struct
> rpc_rqst *req,
> 	struct compound_hdr hdr = {
> 		.minorversion = nfs4_xdr_minorversion(&args-
>>seq_args),
> 	};
> +	uint32_t replen;
> 
> 	encode_compound_hdr(xdr, req, &hdr);
> 	encode_sequence(xdr, &args->seq_args, &hdr);
> 	encode_putfh(xdr, args->fh, &hdr);
> +	replen = hdr.replen + op_decode_hdr_maxsz + 2 + 1;
> 	encode_listxattrs(xdr, args, &hdr);
> 
> -	rpc_prepare_reply_pages(req, args->xattr_pages, 0, args-
>>count,
> -	    hdr.replen);
> +	rpc_prepare_reply_pages(req, args->xattr_pages, 0, args-
>>count, replen);
> 
> 	encode_nops(&hdr);
> }
> --
> 2.28.0
> 
> 
> --
> Trond Myklebust
> Linux NFS client maintainer, Hammerspace
> trond.myklebust@hammerspace.com