From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rolf Eike Beer" Subject: Re: [LSF/MM TOPIC] linux servers as a storage server - what's missing? Date: Thu, 19 Jan 2012 09:16:51 +0100 Message-ID: <5905c624d943d1f90239deec28357cd2.squirrel@webmail.sf-mail.de> References: <4EF2026F.2090506@redhat.com> <4F1706AD.3080405@redhat.com>

Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Cc: "Roland Dreier" , "Ric Wheeler" , linux-fsdevel@vger.kernel.org, "linux-scsi@vger.kernel.org" To: "Bart Van Assche" Return-path: In-Reply-To: Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org > On Wed, Jan 18, 2012 at 6:46 PM, Roland Dreier > wrote: >> > Why would you crash is you have device mapper multipath configured to >> handle >> > path fail over? We have tons of enterprise customers that use that... >> >> cf http://www.spinics.net/lists/linux-scsi/msg56254.html >> >> Basically hot unplug of an sdX can oops on any recent kernel, no >> matter what dm stuff you have on top. >> >> > On the broader topic of error handling and so on, I do agree that is >> always >> > an area of concern (how many times to retry, how long time outs need >> to be, >> > when to panic/reboot or propagate up an error code) >> >> Yes, especially the scsi eh stuff escalating to a host reset when >> a single drive has gone bad -- even if the HBA is happily doing IO >> to other drives, we'll kill access to the whole SAS fabric. > > With which SCSI low-level diver does that occur and how does the call > stack look like ? I haven't encountered any such issues while testing > the srp-ha patch set. However, I have to admit that the issues > mentioned in the description of commit 3308511 were discovered while > testing the srp-ha patch set. Likely unrelated to the stuff above, but this has happened for me. I was changing the USB devices while sending the machine to s2disk and this was what it came up with on resume: [91794.875373] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 [91794.875385] IP: [] sd_revalidate_disk+0x31/0x320 [91794.875396] PGD 3fe33f067 PUD 3fff84067 PMD 0 [91794.875403] Oops: 0000 [#1] PREEMPT SMP [91794.875410] CPU 7 [91794.875412] Modules linked in: autofs4 fuse ip6t_LOG xt_tcpudp xt_pkttype ipt_LOG xt_limit af_packet edd ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_raw xt_NO TRACK ipt_REJECT iptable_raw iptable_filter ip6table_mangle nf_conntrack_netbios_ns nf_conntrack_broadcast nf_conntrack_ipv4 nf_defrag_ipv4 ip_tables xt_conntrack nf_connt rack ip6table_filter ip6_tables x_tables snd_pcm_oss snd_mixer_oss snd_seq snd_seq_device cpufreq_conservative cpufreq_userspace cpufreq_powersave acpi_cpufreq mperf snd_h da_codec_hdmi snd_hda_codec_realtek pl2303 usbserial kvm_intel kvm snd_hda_intel e1000e snd_hda_codec iTCO_wdt shpchp mei(C) xhci_hcd i2c_i801 pci_hotplug iTCO_vendor_supp ort snd_hwdep snd_pcm snd_timer snd soundcore snd_page_alloc sr_mod cdrom sg serio_raw pcspkr linear raid456 async_raid6_recov async_pq raid6_pq async_xor xor async_memcpy async_tx raid10 raid1 raid0 i915 drm_kms_helper drm i2c_algo_bit button video dm_snapshot dm_mod fan processor thermal thermal_sys pata_amd ata_generic sata_nv [last unlo aded: preloadtrace] [91794.875522] [91794.875525] Pid: 5242, comm: udisks-daemon Tainted: G C 3.1.0-46-desktop #1 /DH67CL [91794.875534] RIP: 0010:[] [] sd_revalidate_disk+0x31/0x320 [91794.875543] RSP: 0018:ffff88040399dbb8 EFLAGS: 00010293 [91794.875547] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000001 [91794.875552] RDX: ffff8803fa9ba740 RSI: ffff8803fa9ba760 RDI: ffff8800d3975c00 [91794.875557] RBP: ffff8800d3975c00 R08: ffff88040399db84 R09: ffff8803fb546400 [91794.875561] R10: 0000000000000001 R11: 0000000000000001 R12: 00000000ffffff85 [91794.875565] R13: ffff88041efcb818 R14: ffff8800d3975c00 R15: ffff88040399dc08 [91794.875718] FS: 00007fb7921067a0(0000) GS:ffff88041fbc0000(0000) knlGS:0000000000000000 [91794.875863] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [91794.876016] CR2: 0000000000000008 CR3: 00000003fe33e000 CR4: 00000000000406e0 [91794.876172] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [91794.876321] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [91794.876473] Process udisks-daemon (pid: 5242, threadinfo ffff88040399c000, task ffff8804035fa500) [91794.876596] done. [91794.876772] Stack: [91794.876774] ffff88040399dc08 ffff88041efcb800 0000000000000000 00000000ffffff85 [91794.876777] ffff88041efcb818 ffffffff811c7a98 ffff88041efcb800 000000001efcb800 [91794.876779] ffff8800d3975c78 ffff8800d3975c0c ffff8800d3975c00 0000000000000000 [91794.876782] Call Trace: [91794.876791] [] rescan_partitions+0xa8/0x320 [91794.876797] [] __blkdev_get+0x2be/0x420 [91794.876802] [] blkdev_get+0x62/0x2d0 [91794.876807] [] __dentry_open+0x23a/0x3f0 [91794.876812] [] do_last+0x3f8/0x7b0 [91794.876816] [] path_openat+0xdb/0x400 [91794.876819] [] do_filp_open+0x4d/0xc0 [91794.876823] [] do_sys_open+0x101/0x1e0 [91794.876827] [] system_call_fastpath+0x16/0x1b [91794.876840] [<00007fb79189fb20>] 0x7fb79189fb1f [91794.876841] Code: 86 b0 9e 00 48 89 6c 24 10 48 89 5c 24 08 48 89 fd 4c 89 64 24 18 4c 89 6c 24 20 c1 e8 15 48 8b 9f 28 03 00 00 83 e0 07 83 f8 03 <4c> 8b 63 08 0f 87 8e 02 00 00 41 8b 84 24 50 06 00 00 31 d2 83 [91794.876857] RIP [] sd_revalidate_disk+0x31/0x320 [91794.876860] RSP [91794.876861] CR2: 0000000000000008 Kernel is from openSuSE 12.1: Linux devpool02 3.1.0-46-desktop #1 SMP PREEMPT Mon Oct 24 20:49:37 UTC 2011 (1cba112) x86_64 x86_64 x86_64 GNU/Linux Greetings, Eike