Re: Regression v6.11 booting cannot mount harddisks (xfs)

[Jesper Dangaard Brouer]

Hi Hellwig,

I bisected my boot problem down to this commit:

$ git bisect good
af2814149883e2c1851866ea2afcd8eadc040f79 is the first bad commit
commit af2814149883e2c1851866ea2afcd8eadc040f79
Author: Christoph Hellwig <hch@xxxxxx>
Date:   Mon Jun 17 08:04:38 2024 +0200

    block: freeze the queue in queue_attr_store

    queue_attr_store updates attributes used to control generating I/O, and
    can cause malformed bios if changed with I/O in flight.  Freeze the 
queue
    in common code instead of adding it to almost every attribute.

    Signed-off-by: Christoph Hellwig <hch@xxxxxx>
    Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
    Reviewed-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
    Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
    Reviewed-by: Chaitanya Kulkarni <kch@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20240617060532.127975-12-hch@xxxxxx
    Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>

 block/blk-mq.c    | 5 +++--
 block/blk-sysfs.c | 9 ++-------
 2 files changed, 5 insertions(+), 9 deletions(-)

git describe --contains af2814149883e2c1851866ea2afcd8eadc040f79
v6.11-rc1~80^2~66^2~15


On 10/09/2024 16.49, Jesper Dangaard Brouer wrote:
> On 10/09/2024 15.06, Damien Le Moal wrote:
> > On 2024/09/10 21:19, Jesper Dangaard Brouer wrote:
> > > Hi Linus,
> > >
> > > My testlab kernel devel server isn't booting correctly on v6.11 branches
> > > (e.g. net-next at 6.11.0-rc5)
> > > I just confirmed this also happens on your tree tag: v6.11-rc7.
> > >
> > > The symptom/issue is that harddisk dev names (e.g /dev/sda, /dev/sdb,
> > > /dev/sdc) gets reordered.  I switched /etc/fstab to use UUID's instead
> > > (which boots on v6.10) but on 6.11 it still cannot mount harddisks and
> > > doesn't fully boot.
> >
> > Parallel SCSI device scanning has been around for a long time... This is
> > controlled with CONFIG_SCSI_SCAN_ASYNC. And yes, that can cause disk 
> > names to
> > change, which is why it is never a good idea to rely on them but 
> > instead use
> > /dev/disk/by-* names. Disabling CONFIG_SCSI_SCAN_ASYNC will likely not 
> > guarantee
> > that disk names will be constant, given that you seem to have 2 AHCI 
> > adapters on
> > your host and PCI device scanning is done in parallel.
> >
> > > E.g. errors:
> > >     systemd[1]: Expecting device
> > > dev-disk-by\x2duuid-0c2b348d\x2de013\x2d482b\x2da91c\x2d029640ec427a.device
> > > - /dev/disk/by-uuid/0c2b348d-e013-482b-a91c-029640ec42
> > > 7a...
> > >     [DEPEND] Dependency failed for var-lib.mount - /var/lib.
> > >     [...]
> > >     [ TIME ] Timed out waiting for device
> > > dev-d…499e46-b40d-4067-afd4-5f6ad09fcff2.
> > >     [DEPEND] Dependency failed for boot.mount - /boot.
> > >
> > > That corresponds to fstab's:
> > >    - UUID=8b499e46-b40d-4067-afd4-5f6ad09fcff2 /boot     xfs defaults 
> > > 0 0
> > >    - UUID=0c2b348d-e013-482b-a91c-029640ec427a /var/lib/ xfs defaults 
> > > 0 0
> > >
> > > It looks like disk controller initialization happens in *parallel* on
> > > these newer kernels as dmesg shows init printk's overlapping:
> > >
> > >    [    5.683393] scsi 5:0:0:0: Direct-Access     ATA      SAMSUNG
> > > MZ7KM120 003Q PQ: 0 ANSI: 5
> > >    [    5.683641] scsi 7:0:0:0: Direct-Access     ATA      SAMSUNG
> > > MZ7KM120 003Q PQ: 0 ANSI: 5
> > >    [    5.683797] scsi 8:0:0:0: Direct-Access     ATA      Samsung SSD
> > > 840  BB0Q PQ: 0 ANSI: 5
> > >    [...]
> > >    [    7.057376] sd 5:0:0:0: [sda] 234441648 512-byte logical blocks:
> > > (120 GB/112 GiB)
> > >    [    7.062279] sd 7:0:0:0: [sdb] 234441648 512-byte logical blocks:
> > > (120 GB/112 GiB)
> > >    [    7.070628] sd 5:0:0:0: [sda] Write Protect is off
> > >    [    7.070701] sd 8:0:0:0: [sdc] 488397168 512-byte logical blocks:
> > > (250 GB/233 GiB)
> > >
> > > Perhaps this could be a hint to what changed?
> >
> > See above. The disk /dev/sdX names not being reliable is rather normal.
> > Are you sure you have the correct UUIDs of your FSes on the disks ? 
> > You can
> > check them with "blkid /dev/sdX[n]"
>
> I have checked that I use the correct UUIDs.
>
> I checked my /etc/fstab have the UUID entries under /dev/disk/by-uuid/
> via this oneliner, which needs to have a /etc/fstab entry under each
> UUID. We can see I have one partition that I'm not using
> (0fd3bc38-6496-401f-87f2-87e09532de53), which is expected.
>
> $ for UUID in $(ls /dev/disk/by-uuid/); do echo $UUID; grep -H $UUID 
> /etc/fstab; done
> 09e8c15f-80d2-47e3-8e73-d3fdfcf33eef
> /etc/fstab:UUID=09e8c15f-80d2-47e3-8e73-d3fdfcf33eef /     xfs     
> defaults        0 0
> 0c2b348d-e013-482b-a91c-029640ec427a
> /etc/fstab:UUID=0c2b348d-e013-482b-a91c-029640ec427a    /var/lib/        
> xfs defaults 0 0
> 0fd3bc38-6496-401f-87f2-87e09532de53
> 581920da-1ccb-4b25-856c-036310032a74
> /etc/fstab:UUID=581920da-1ccb-4b25-856c-036310032a74    /nix            
> xfs    defaults 0 0
> 8b499e46-b40d-4067-afd4-5f6ad09fcff2
> /etc/fstab:UUID=8b499e46-b40d-4067-afd4-5f6ad09fcff2 /boot     xfs     
> defaults        0 0
> cd409a50-0371-47ca-9213-49a2bc7b9317
> /etc/fstab:UUID=cd409a50-0371-47ca-9213-49a2bc7b9317 swap     swap    
> defaults        0 0
>
>
> > > Any hints what commit I should try to test revert?
> > > Or good starting point for bisecting?
> >
> > You said that 6.10 works, so maybe start from there ?
>
> I tested I could boot tag v6.10, and have started bisection.
>
> I've not tried to deselect CONFIG_SCSI_SCAN_ASYNC as the kernel that
> worked on tag v6.10 also had this CONFIG_SCSI_SCAN_ASYNC enabled. So, it
> is likely not related to the async controller init.
>
> --Jesper