On Tue, Nov 22, 2011 at 01:03:37PM +0100, Michał Mirosław wrote: > On Tue, Nov 22, 2011 at 12:26:57PM +1100, NeilBrown wrote: > > On Tue, 22 Nov 2011 01:50:37 +0100 Michał Mirosław <mirq-linux@xxxxxxxxxxxx> > > wrote: > > > > > On Mon, Nov 21, 2011 at 07:27:45PM +1100, NeilBrown wrote: > > > > On Mon, 21 Nov 2011 08:04:30 +0100 James Bottomley > > > > <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> wrote: > > > > > On Mon, 2011-11-21 at 12:37 +1100, NeilBrown wrote: > > > > > > Thank for the report. > > > > > > However as this crash is clearly in the SCSI layer it makes sense to reported > > > > > > it to linux-scsi - so I have cc:ed this reply there. > > > > > > > > > > > > On Sat, 19 Nov 2011 14:41:39 +0100 Michał Mirosław <mirq-linux@xxxxxxxxxxxx> > > > > > > wrote: > > > > > > > I get following BUG_ON tripped while booting, before rootfs is mounted by > > > > > > > Debian's initrd. This started to happen for kernels since sometime > > > > > > > during 3.1-rcX. > > > > > > > > > > > > > > [ 6.246170] ------------[ cut here ]------------ > > > > > > > [ 6.246246] kernel BUG at /mnt/src-tmp/jaja/git/qmqm/drivers/scsi/scsi_lib.c:1153! > > > > > > > > > > I can tell you what it is: > > > > > > > > > > /* > > > > > * Filesystem requests must transfer data. > > > > > */ > > > > > BUG_ON(!req->nr_phys_segments); > > > > > > > > > > But the fault is in the layer above SCSI. It means something sent a > > > > > request with REQ_TYPE_FS but no actual data attached ... this is > > > > > supposed to be impossible, hence the bug on. > > > > > > > > Thanks.... that sounds strangely familiar, but I cannot be sure and google > > > > doesn't help. > > > > > > > > Michał: what are you using on the RAID1 - some filesystem (which one)or swap or something else? > > > > > > The whole stack is: ext4 over lvm over dm-crypt over md-raid1 over SATA > > > drives. The boot doesn't survive to the point where the initrd script asks > > > for md-crypt's key password. > > > > > > > That gives us lots of room for pointing the finger of blame, doesn't it? > > I think it is -> his problem. :-) > > > > From the md part of the stack trace it looks most like a write request. It > > could be a retried read, but that is extremely unlike that early in boot. > > > > So presumably it is some sort of zero-length REQ_FLUSH or something like that. > > md/raid1 will just pass those unchanged down. > > My guess is that ext4 is generating this and something in the stack is > > stripping the REQ_FLUSH .... though why it even tries before asking for a > > password is beyond me. > > I pointed finger at md because when dm-crypt is not yet set up > then only thing working is the array. All filesystems need the > dm-crypt mapping first. > > From the dmesg on 3.0, I see that NCQ is enabled but FUA is not: > > [ 2.269487] ata1: SATA max UDMA/133 abar m2048@0xfbd25000 port 0xfbd25100 irq 64 > [ 2.588395] ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300) > [ 2.588979] ata1.00: ATA-8: KINGSTON SV100S264G, D110225a, max UDMA/100 > [ 2.589037] ata1.00: 125045424 sectors, multi 16: LBA48 NCQ (depth 31/32), AA > [ 2.589321] ata1.00: configured for UDMA/100 > [ 2.589440] scsi 1:0:0:0: Direct-Access ATA KINGSTON SV100S2 D110 PQ: 0 ANSI: 5 > [ 2.631113] sd 1:0:0:0: [sda] 125045424 512-byte logical blocks: (64.0 GB/59.6 GiB) > [ 2.631265] sd 1:0:0:0: [sda] Write Protect is off > [ 2.631267] sd 1:0:0:0: [sda] Mode Sense: 00 3a 00 00 > [ 2.631296] sd 1:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA > [ 2.632119] sd 1:0:0:0: [sda] Attached SCSI disk > > [ 2.269557] ata2: SATA max UDMA/133 abar m2048@0xfbd25000 port 0xfbd25180 irq 64 > [ 2.588916] ata2: SATA link up 3.0 Gbps (SStatus 123 SControl 300) > [ 2.628336] ata2.00: ATA-8: ST9500420AS, 0002SDM1, max UDMA/133 > [ 2.628396] ata2.00: 976773168 sectors, multi 16: LBA48 NCQ (depth 31/32) > [ 2.630143] ata2.00: configured for UDMA/133 > [ 2.630238] scsi 2:0:0:0: Direct-Access ATA ST9500420AS 0002 PQ: 0 ANSI: 5 > [ 2.631236] sd 2:0:0:0: [sdb] 976773168 512-byte logical blocks: (500 GB/465 GiB) > [ 2.631792] sd 2:0:0:0: [sdb] Write Protect is off > [ 2.632031] sd 2:0:0:0: [sdb] Mode Sense: 00 3a 00 00 > [ 2.632050] sd 2:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA > [ 2.636038] sd 2:0:0:0: [sdb] Attached SCSI disk > > There's two RAID1 array on both of the disks, and one more RAID1 (with second > leg missing) on sdb. I just remembered that the sdb leg of the main array has write-mostly flag set. I checked /proc/mdstat from running system and it turns out that now I have both legs marked so. Does this ring a bell? cat /proc/mdstat Personalities : [raid1] md2 : active (auto-read-only) raid1 sdb3[0] 425862712 blocks super 1.2 [2/1] [U_] md1 : active raid1 sda2[3](W) sdb2[2](W) 62396688 blocks super 1.2 [2/2] [UU] md0 : active raid1 sda1[0] sdb1[1] 123892 blocks super 1.2 [2/2] [UU] unused devices: <none> Best Regards, Michał Mirosław -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel