On 15-04-14 06:52 PM, Sagi Grimberg wrote:
When I set up a DIX enabled device for the first time (say scsi_debug) it all works, but when I remove it and set it up again I get the below crash: Reproducer: $modprobe scsi_debug dif=1 dix=1 $modprobe -r scsi_debug $modprobe scsi_debug dif=1 dix=1
Using lk 4.0.0 # modprobe scsi_debug dif=1 dix=1 # modprobe -r scsi_debug # modprobe scsi_debug dif=1 dix=1 locks up my laptop. So does: # modprobe scsi_debug dif=1 dix=1 # modprobe -r scsi_debug # modprobe scsi_debug No useful information is logged in both cases. However, take out the dif/dix stuff and it's okay: # modprobe scsi_debug # modprobe -r scsi_debug # modprobe scsi_debug So it is dif/dix related. Looking a little closer it seems to be related to removing a dix/dif host (and its associated lu(s)): # modprobe scsi_debug dif=1 dix=1 # echo -1 > /sys/bus/pseudo/drivers/scsi_debug/add_host # echo 1 > /sys/bus/pseudo/drivers/scsi_debug/add_host <laptop freezes> The above modprobe adds on scsi_debug dif/dix host with one lu. The "echo -1 >" removes that host while the "echo 1 >" attempts to re-add that dif/dix host. My guess is that the scsi mid-level has dtor problems cleaning up a dif/dix host and/or its associated lu(s). Doug Gilbert
It seems that somehow bdi_destroy() is not invoked for DIX... scsi_debug_init: dif_storep 131072 bytes @ ffffc90018507000 scsi_debug: host protection DIF1 DIX1 scsi host9: scsi_debug, version 1.85 [20141022], dev_size_mb=8, opts=0x0 scsi 9:0:0:0: Direct-Access Linux scsi_debug 0184 PQ: 0 ANSI: 6 sd 9:0:0:0: Attached scsi generic sg2 type 0 sd 9:0:0:0: [sdc] Enabling DIF Type 1 protection sd 9:0:0:0: [sdc] 16384 512-byte logical blocks: (8.38 MB/8.00 MiB) sd 9:0:0:0: [sdc] Write Protect is off sd 9:0:0:0: [sdc] Write cache: enabled, read cache: enabled, supports DPO and FUA sd 9:0:0:0: [sdc] Enabling DIX T10-DIF-TYPE1-CRC protection sd 9:0:0:0: [sdc] DIF application tag size 2 sd 9:0:0:0: [sdc] Attached SCSI disk sd 9:0:0:0: [sdc] Synchronizing SCSI cache scsi_debug_init: dif_storep 131072 bytes @ ffffc900185e7000 scsi_debug: host protection DIF1 DIX1 scsi host10: scsi_debug, version 1.85 [20141022], dev_size_mb=8, opts=0x0 scsi 10:0:0:0: Direct-Access Linux scsi_debug 0184 PQ: 0 ANSI: 6 sd 10:0:0:0: Attached scsi generic sg2 type 0 sd 10:0:0:0: [sdc] Enabling DIF Type 1 protection sd 10:0:0:0: [sdc] 16384 512-byte logical blocks: (8.38 MB/8.00 MiB) sd 10:0:0:0: [sdc] Write Protect is off sd 10:0:0:0: [sdc] Write cache: enabled, read cache: enabled, supports DPO and FUA ------------[ cut here ]------------ WARNING: CPU: 2 PID: 753 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x65/0x80() sysfs: cannot create duplicate filename '/devices/virtual/bdi/8:32' ---[ end trace 08a96f4c6fca987b ]--- ------------[ cut here ]------------ WARNING: CPU: 2 PID: 753 at lib/kobject.c:240 kobject_add_internal+0x194/0x1f0() ---[ end trace 08a96f4c6fca987c ]--- BUG: unable to handle kernel NULL pointer dereference at 0000000000000040 IP: [<ffffffff811cbede>] sysfs_do_create_link_sd+0x3e/0xc0 PGD 0 Oops: 0000 [#1] SMP Modules linked in: netconsole tcm_loop vhost_scsi vhost ib_srpt ib_isert iscsi_target_mod rdma_cm ib_cm iw_cm ib_sa ib_mad ib_core ib_addr tcm_fc libfc target_core_file target_core_iblock target_core_pscsi target_core_mod configfs nfsd exportfs nfsv3 nfs_acl rpcsec_gss_krb5 auth_rpcgss nfsv4 nfs fscache lockd grace autofs4 sunrpc cpufreq_ondemand ipv6 ext4 jbd2 dm_mirror dm_region_hash dm_log uinput iTCO_wdt iTCO_vendor_support microcode serio_raw pcspkr ipmi_si ipmi_msghandler acpi_cpufreq sg sb_edac edac_core i2c_i801 lpc_ich mfd_core shpchp ioatdma igb dm_mod dca i2c_algo_bit i2c_core ptp pps_core wmi ext3(E) jbd(E) mbcache(E) sd_mod(E) ahci(E) libahci(E) isci(E) libsas(E) scsi_transport_sas(E) qla2xxx(E) scsi_transport_fc(E) [last unloaded: netconsole] CPU: 4 PID: 753 Comm: kworker/u49:6 Tainted: G W E 4.0.0-rc1+ #38 Hardware name: Supermicro SYS-1027R-WRF/X9DRW, BIOS 3.0a 08/08/2013 Workqueue: events_unbound async_run_entry_fn task: ffff88046de44410 ti: ffff88046b754000 task.ti: ffff88046b754000 RIP: 0010:[<ffffffff811cbede>] [<ffffffff811cbede>] sysfs_do_create_link_sd+0x3e/0xc0 RSP: 0018:ffff88046b757cf8 EFLAGS: 00010246 RAX: 00000000112e112e RBX: ffffffff817d2813 RCX: 0000000000000001 RDX: 000000000000112e RSI: 0000000000000010 RDI: ffffffff81e440c8 RBP: ffff88046b757d28 R08: ffff880468270f50 R09: 0000000000000040 R10: 0000000000000001 R11: 0000000000000010 R12: ffff880079b92988 R13: 0000000000000010 R14: 0000000000000001 R15: ffff88046fa0ae05 FS: 0000000000000000(0000) GS:ffff88047fc80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000040 CR3: 0000000001a0e000 CR4: 00000000000406e0 Stack: ffff88046b757d38 ffff88046ddea000 ffff88046b806008 ffff88046ddea080 0000000000000000 ffff88046fa0ae05 ffff88046b757d38 ffffffff811cbfb1 ffff88046b757d78 ffffffff81231c60 ffff88046b806008 008000206e800800 Call Trace: [<ffffffff811cbfb1>] sysfs_create_link+0x21/0x40 [<ffffffff81231c60>] add_disk+0x1b0/0x310 [<ffffffffa01306ec>] sd_probe_async+0x11c/0x1d0 [sd_mod] [<ffffffff8106d525>] async_run_entry_fn+0x55/0x160 [<ffffffff81066126>] process_one_work+0x136/0x3a0 [<ffffffff810664a7>] worker_thread+0x117/0x3b0 [<ffffffff81066390>] ? process_one_work+0x3a0/0x3a0 [<ffffffff81066390>] ? process_one_work+0x3a0/0x3a0 [<ffffffff8106afbe>] kthread+0xce/0xf0 [<ffffffff8106aef0>] ? kthread_freezable_should_stop+0x70/0x70 [<ffffffff81542e6c>] ret_from_fork+0x7c/0xb0 [<ffffffff8106aef0>] ? kthread_freezable_should_stop+0x70/0x70 Code: 48 89 d3 4c 89 6d e8 4c 89 75 f0 49 89 fc 4c 89 7d f8 49 89 f5 41 89 ce 74 6e 48 85 ff 74 69 48 c7 c7 c8 40 e4 81 e8 52 6b 37 00 <4d> 8b 6d 30 4d 85 ed 74 08 4c 89 ef e8 01 c7 ff ff 66 83 05 d1 RIP [<ffffffff811cbede>] sysfs_do_create_link_sd+0x3e/0xc0 RSP <ffff88046b757cf8> CR2: 0000000000000040 ---[ end trace 08a96f4c6fca987d ]--- BUG: unable to handle kernel paging request at ffffffffffffffd8 --
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