Jeff Layton 849dc3244c nfs4: nfs4_ff_layout_prepare_ds should return NULL if connection failed ... I hit the following oops out of the blue while testing with flexfiles: BUG: unable to handle kernel NULL pointer dereference at 00000000000000e8 IP: [<ffffffffa048f6b8>] nfs4_ff_find_or_create_ds_client+0x48/0x50 [nfs_layout_flexfiles] PGD 44031067 PUD 5062d067 PMD 0 Oops: 0000 [#1] SMP Modules linked in: nfsv3 nfs_layout_flexfiles tun rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache dcdbas nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw bonding ipmi_devintf ipmi_msghandler snd_hda_codec_generic virtio_balloon ppdev snd_hda_intel snd_hda_controller snd_hda_codec iosf_mbi crct10dif_pclmul crc32_pclmul ghash_clmulni_intel snd_hda_core parport_pc snd_hwdep parport snd_seq snd_seq_device snd_pcm snd_timer acpi_cpufreq snd soundcore i2c_piix4 xfs libcrc32c joydev virtio_net virtio_console qxl drm_kms_helper ttm crc32c_intel drm virtio_pci serio_raw ata_generic virtio_ring virtio pata_acpi CPU: 0 PID: 19138 Comm: test5 Not tainted 4.1.9-100.pd.90.el7.x86_64 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.8.2-20150714_191134- 04/01/2014 task: ffff88007b70cf00 ti: ffff88004cc44000 task.ti: ffff88004cc44000 RIP: 0010:[<ffffffffa048f6b8>] [<ffffffffa048f6b8>] nfs4_ff_find_or_create_ds_client+0x48/0x50 [nfs_layout_flexfiles] RSP: 0018:ffff88004cc47890 EFLAGS: 00010246 RAX: 0000000000000003 RBX: ffff880050932300 RCX: ffff88006978f488 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88003e0e8540 RBP: ffff88004cc47908 R08: 0000000000000000 R09: 0000000000000000 R10: ffff88007ff8c758 R11: 0000000000000005 R12: ffff88003e0e8540 R13: 0000000000000000 R14: ffff88006978f488 R15: ffff88004431cc80 FS: 00007fea40c7c740(0000) GS:ffff88007fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000000e8 CR3: 0000000044318000 CR4: 00000000000406f0 Stack: ffffffffa048c934 ffff880050932310 0000000100000001 ffff88006978f510 ffff88006978f3c8 ffff88003e56cd90 ffff88004cc479d0 00000020a052aff0 000000000004b000 ffff88004cc47908 ffff880050932300 ffff88004cc479d0 Call Trace: [<ffffffffa048c934>] ? ff_layout_write_pagelist+0x64/0x220 [nfs_layout_flexfiles] [<ffffffffa057a3bf>] pnfs_generic_pg_writepages+0xaf/0x1b0 [nfsv4] [<ffffffffa051ab57>] nfs_pageio_doio+0x27/0x60 [nfs] [<ffffffffa051bfe4>] nfs_pageio_complete_mirror+0x54/0xa0 [nfs] [<ffffffffa051c7ad>] nfs_pageio_complete+0x2d/0x90 [nfs] [<ffffffffa052032d>] nfs_writepage_locked+0x8d/0xe0 [nfs] [<ffffffff811e4630>] ? page_referenced_one+0x1a0/0x1a0 [<ffffffffa05210e7>] nfs_wb_single_page+0xf7/0x190 [nfs] [<ffffffffa05108d1>] nfs_launder_page+0x41/0x90 [nfs] [<ffffffff811b8930>] invalidate_inode_pages2_range+0x340/0x3a0 [<ffffffff811b89a7>] invalidate_inode_pages2+0x17/0x20 [<ffffffffa0513e1e>] nfs_release+0x9e/0xb0 [nfs] [<ffffffffa050fa1d>] nfs_file_release+0x3d/0x60 [nfs] [<ffffffff8122481c>] __fput+0xdc/0x1e0 [<ffffffff8122496e>] ____fput+0xe/0x10 [<ffffffff810bde67>] task_work_run+0xa7/0xe0 [<ffffffff810af735>] get_signal+0x565/0x600 [<ffffffff811a9815>] ? __filemap_fdatawrite_range+0x65/0x90 [<ffffffff810144a7>] do_signal+0x37/0x730 [<ffffffffa0569921>] ? nfs4_file_fsync+0x81/0x150 [nfsv4] [<ffffffff81254dbb>] ? vfs_fsync_range+0x3b/0xb0 [<ffffffff811446a6>] ? __audit_syscall_exit+0x1e6/0x280 [<ffffffff81014bff>] do_notify_resume+0x5f/0xa0 [<ffffffff8178ec3c>] int_signal+0x12/0x17 Code: 48 8b 40 70 8b 00 83 f8 03 74 20 83 f8 04 75 13 55 48 89 ce 48 89 d7 48 89 e5 e8 14 0f 0e 00 5d c3 66 90 0f 0b 66 0f 1f 44 00 00 <48> 8b 82 e8 00 00 00 c3 66 66 66 66 90 55 48 89 e5 41 57 41 56 RIP [<ffffffffa048f6b8>] nfs4_ff_find_or_create_ds_client+0x48/0x50 [nfs_layout_flexfiles] RSP <ffff88004cc47890> CR2: 00000000000000e8 When the DS connection attempt fails, nfs4_ff_layout_prepare_ds marks it for the error but then just returns the ds as if it were usable. The comments though say: /* Upon return, either ds is connected, or ds is NULL */ Ensure that we set the return pointer to NULL in the event that the connection attempt fails. Signed-off-by: Jeff Layton <jeff.layton@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>		2016-03-16 15:46:48 -04:00
..
flexfilelayout.c	NFS: Cleanup - rename NFS_LAYOUT_RETURN_BEFORE_CLOSE	2016-01-27 20:40:05 -05:00
flexfilelayout.h	pNFS/flexfiles: Support server-supplied layoutstats sampling period	2015-12-28 14:32:36 -05:00
flexfilelayoutdev.c	nfs4: nfs4_ff_layout_prepare_ds should return NULL if connection failed	2016-03-16 15:46:48 -04:00
Makefile	pnfs/flexfiles: Add the FlexFile Layout Driver	2015-02-03 11:06:52 -08:00