(gdb) bt full
#0  0x00007f88ccb2d989 in raise () from /lib64/libc.so.6
No symbol table info available.
#1  0x00007f88ccb2f098 in abort () from /lib64/libc.so.6
No symbol table info available.
#2  0x00007f88ccb268f6 in __assert_fail_base () from /lib64/libc.so.6
No symbol table info available.
#3  0x00007f88ccb269a2 in __assert_fail () from /lib64/libc.so.6
No symbol table info available.
#4  0x00007f88d1fd0f32 in bdrv_open_common (bs=bs@entry=0x7f88d4eeb010, file=file@entry=0x0, 
    options=options@entry=0x7f88d4eeba20, flags=flags@entry=24802, drv=drv@entry=0x7f88d25c0740 <bdrv_iscsi>, 
    errp=0x7fffcc973620) at block.c:850
        ret = 0
        open_flags = <optimized out>
        filename = 0x7f88d4d57250 ""
        local_err = 0x0
        __PRETTY_FUNCTION__ = "bdrv_open_common"
#5  0x00007f88d1fd54fc in bdrv_file_open (pbs=pbs@entry=0x7fffcc9736a0, 
    filename=filename@entry=0x7f88d4ee8500 "iscsi://10.66.9.107/iqn.2008-09.com.example:server.target2/0", 
    options=0x7f88d4eeba20, flags=24802, errp=errp@entry=0x7fffcc9736b0) at block.c:948
        bs = 0x7f88d4eeb010
        drv = 0x7f88d25c0740 <bdrv_iscsi>
        drvname = <optimized out>
        allow_protocol_prefix = <optimized out>
        local_err = 0x0
        ret = <optimized out>
#6  0x00007f88d1fd5a06 in bdrv_open (bs=0x7f88d4ee85c0, 
    filename=filename@entry=0x7f88d4ee8500 "iscsi://10.66.9.107/iqn.2008-09.com.example:server.target2/0", 
    options=0x7f88d4ee8fd0, options@entry=0x7f88d4d843d0, flags=8418, drv=drv@entry=0x7f88d25c2560 <bdrv_raw>, 
    errp=errp@entry=0x7fffcc975758) at block.c:1171
        ret = <optimized out>
        tmp_filename = "\320\367\325Ԉ\177\000\000\000\370\325Ԉ\177", '\000' <repeats 26 times>, "z]\224Έ\177\000\000\001\000\000\000\377\177\000\000\000\200\356ш\177\000\000/usr/lib64/sasl2/\000\023Ɉ\177\000\000\342Q\317ш\177\000\000@M\227\314\377\177\000\000\060M\227\314\377\177\000\000\233U\307̈\177\000\000\001\000\000\000\000\000\000\000\220U\307̈\177\000\000\271\372\263̈\177\000\000\001\000\000\000\377\177\000\000\000\220\356ш\177\000\000 G\227\314\377\177\000\000ho\226ʈ\177\000\000\024\000\000\000\000\000\000\000\342Q\317ш\177\000\000\001\000\000\000\377\177\000\000\240\251\356ш\177\000\000\260M\227\314\377"...
        file = 0x0
        file_options = 0x7f88d4ee9ff0
        drvname = <optimized out>
        local_err = 0x0
        __PRETTY_FUNCTION__ = "bdrv_open"
#7  0x00007f88d20050df in blockdev_init (bs_opts=bs_opts@entry=0x7f88d4d843d0, type=type@entry=IF_NONE, 
    errp=errp@entry=0x7fffcc975830) at blockdev.c:516
        buf = <optimized out>
        file = 0x7f88d4ee8500 "iscsi://10.66.9.107/iqn.2008-09.com.example:server.target2/0"
        serial = 0x0
        ro = <optimized out>
        bdrv_flags = 226
        on_read_error = <optimized out>
        on_write_error = 2
        dinfo = 0x7f88d4ee8550
        io_limits = {bps = {0, 0, 0}, iops = {0, 0, 0}}
        snapshot = 0
        copy_on_read = false
        ret = <optimized out>
        error = 0x0
        opts = 0x7f88d4d67810
        id = <optimized out>
        has_driver_specific_opts = false
        drv = 0x7f88d25c2560 <bdrv_raw>
#8  0x00007f88d2005cdf in drive_init (all_opts=0x7f88d4d57030, block_default_type=<optimized out>) at blockdev.c:859
        value = <optimized out>
        dinfo = 0x0
        bs_opts = 0x7f88d4d843d0
        legacy_opts = 0x7f88d4d83850
        media = <optimized out>
        type = IF_NONE
        cyls = 0
        secs = <optimized out>
        translation = 0
        max_devs = 0
        bus_id = 0
        unit_id = <optimized out>
        index = <optimized out>
        devaddr = 0x0
        read_only = <optimized out>
        copy_on_read = <optimized out>
        local_err = 0x0
        __PRETTY_FUNCTION__ = "drive_init"
#9  0x00007f88d20fd34b in drive_init_func (opts=<optimized out>, opaque=<optimized out>) at vl.c:1076
        block_default_type = <optimized out>
#10 0x00007f88d221155b in qemu_opts_foreach (list=<optimized out>, func=func@entry=0x7f88d20fd340 <drive_init_func>, 
    opaque=opaque@entry=0x7f88d25f5170 <pc_machine_rhel700+48>, abort_on_failure=abort_on_failure@entry=1)
    at util/qemu-option.c:1149
        loc = {kind = LOC_CMDLINE, num = 2, ptr = 0x7fffcc975dc8, prev = 0x7f88d2e21340 <std_loc>}
        opts = 0x7f88d4d57030
        rc = 0
#11 0x00007f88d1fbd1fd in main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) at vl.c:4137
        i = <optimized out>
        snapshot = 0
        linux_boot = 0
        icount_option = 0x0
        initrd_filename = 0x0
        kernel_filename = 0x0
        kernel_cmdline = 0x7f88d2269e60 ""
        boot_order = 0x7f88d22220c6 "cad"
        ds = <optimized out>
        cyls = 0
        heads = 0
        secs = 0
        translation = 0
        hda_opts = <optimized out>
        opts = 0x7f88d4d56690
        machine_opts = <optimized out>
        olist = <optimized out>
        optind = 48
        optarg = 0x7fffcc9777a8 "scsi-hd,drive=drive-data-disk,bus=scsi1.0,id=data-disk"
        loadvm = 0x0
        machine = 0x7f88d25f5140 <pc_machine_rhel700>
        cpu_model = 0x0
        vga_model = 0x7f88d224bbab "none"
        pid_file = 0x0
        incoming = 0x0
        show_vnc_port = 0
        defconfig = <optimized out>
        userconfig = false
        log_mask = <optimized out>
        log_file = 0x0
        mem_trace = {malloc = 0x7f88d20fdaf0 <malloc_and_trace>, realloc = 0x7f88d20fdad0 <realloc_and_trace>, 
          free = 0x7f88d20fdac0 <free_and_trace>, calloc = 0x0, try_malloc = 0x0, try_realloc = 0x0}
        trace_events = 0x0
        trace_file = 0x0
        __PRETTY_FUNCTION__ = "main"
        args = {machine = 0x7fffcc9773ed, ram_size = 140225614321176, boot_device = 0x18 <Address 0x18 out of bounds>, 
          kernel_filename = 0xffff80003368a551 <Address 0xffff80003368a551 out of bounds>, 
          kernel_cmdline = 0x2 <Address 0x2 out of bounds>, initrd_filename = 0x0, 
          cpu_model = 0x7fff00000030 <Address 0x7fff00000030 out of bounds>}
(gdb)

# /usr/libexec/qemu-kvm -M pc -enable-kvm -m 4096 -smp 4 -no-kvm-pit-reinjection -usb -device usb-tablet,id=input0 -name sluo -uuid 990ea161-6b67-47b2-b803-19fb01d30d30 -rtc base=localtime,clock=host,driftfix=slew -drive file=/home/RHEL_7.0_20140212.1_Server_x86_64.qcow2,if=none,id=drive-system-disk,format=qcow2,cache=none,aio=native,werror=stop,rerror=stop -device virtio-blk-pci,vectors=0,bus=pci.0,addr=0x4,scsi=off,drive=drive-system-disk,id=system-disk,bootindex=1 -netdev tap,id=hostnet0,vhost=on,script=/etc/qemu-ifup -device virtio-net-pci,netdev=hostnet0,id=virtio-net-pci0,mac=00:01:02:03:40:21,bus=pci.0,addr=0x5 -k en-us -boot menu=on -qmp tcp:0:5555,server,nowait -serial unix:/tmp/ttyS0,server,nowait -vnc :1 -spice disable-ticketing,port=5931 -monitor stdio -drive file=iscsi://10.66.9.107/iqn.2008-09.com.example:server.target2/0,if=none,id=drive-data-disk,format=raw,cache=none,aio=native -iscsi id=iqn1,user=redhat,password=redhat -device virtio-scsi-pci,id=scsi1,bus=pci.0,addr=0x7 -device scsi-hd,drive=drive-data-disk,bus=scsi1.0,id=data-disk

Please retry with /1 instead of /0 at the end of the iscsi URL.

*** Bug 1062841 has been marked as a duplicate of this bug. ***

I can reproduce it with /0.  It is a bit ugly to assert this way, it should be fixed.

It is not related to CHAP authentication, the following is enough

IQN=iqn.2003-01.org.linux-iscsi.san01.x8664:sn.05135a0e4a11
URL=iscsi://127.0.0.1/$IQN/0
IMAGE=~/test2.img
service tgtd start
tgtadm --lld iscsi --op new --mode target --tid 1 -T $IQN
tgtadm --lld iscsi --op new --mode logicalunit --tid 1 --lun 1 -b $IMAGE
tgtadm --lld iscsi --op new --mode portal --param portal=127.0.0.1:3260
tgtadm --lld iscsi --op bind --mode target --tid 1 -I ALL
/usr/libexec/qemu-kvm -vnc :1 -drive if=ide,file=$URL

*** Bug 1062840 has been marked as a duplicate of this bug. ***

(In reply to Paolo Bonzini from comment #3)
> Please retry with /1 instead of /0 at the end of the iscsi URL.

Use /1 is OK, but /0 will meet this bug(qemu-kvm: block.c:850: bdrv_open_common: Assertion `bs->request_alignment != 0' failed. Aborted (core dumped)).

# uname -r && rpm -q qemu-kvm && rpm -q libiscsi
3.10.0-86.el7.x86_64
qemu-kvm-1.5.3-47.el7.x86_64
libiscsi-1.9.0-6.el7.x86_64

e.g1:...-drive file=iscsi://10.66.9.107/iqn.2008-09.com.example:server.target2/1,if=none,id=drive-data-disk,format=raw,cache=none,aio=native -iscsi id=iqn1,user=redhat,password=redhat -device virtio-scsi-pci,id=scsi1,bus=pci.0,addr=0x7 -device scsi-hd,drive=drive-data-disk,bus=scsi1.0,id=data-disk

Above e.g1 is ok which can boot up guest successfully and detect the libiscsi disk in guest correctly.

e.g2:...-drive file=iscsi://10.66.9.107/iqn.2008-09.com.example:server.target2/0,if=none,id=drive-data-disk,format=raw,cache=none,aio=native -iscsi id=iqn1,user=redhat,password=redhat -device virtio-scsi-pci,id=scsi1,bus=pci.0,addr=0x7 -device scsi-hd,drive=drive-data-disk,bus=scsi1.0,id=data-disk

Above e.g2 meet bug 1067784 which qemu-kvm: block.c:850: bdrv_open_common: Assertion `bs->request_alignment != 0' failed. Aborted (core dumped).

# iscsi-ls -s iscsi://redhat:redhat.9.107:3260/iqn.2008-09.com.example:server.target2
Target:iqn.2008-09.com.example:server.target2 Portal:10.66.9.107:3260,1
Lun:0    Type:STORAGE_ARRAY_CONTROLLER
Lun:1    Type:DIRECT_ACCESS (Size:99M)
Lun:2    Type:DIRECT_ACCESS (Size:99M)

(In reply to Paolo Bonzini from comment #5)
> I can reproduce it with /0.  It is a bit ugly to assert this way, it should
> be fixed.

Can you explain why you think that the problem is with the assertion and not
with the iscsi block driver? An alignment of 0 certainly looks wrong (if there
is no specific requirement, it should be 1).

I think the alignment should not be checked if bs->sg is true.  request_alignment is never used for bs->sg, and a value of zero should be fine.

If you prefer to take part of this "if":

    /* For /dev/sg devices the alignment is not really used.
       With buffered I/O, we don't have any restrictions. */
    if (bs->sg || !(s->open_flags & O_DIRECT)) {
        bs->request_alignment = 1;
        s->buf_align = 1;
        return;
    }

and move it to generic code, that's also fine, but I think an invalid value (such as 0) is better for the bs->sg case.

Oh, okay, I wasn't aware that iscsi uses bs->sg. They are special indeed, so I'm
okay with skipping the test for them. (In fact, they are so special that I would
prefer if they weren't a BlockDriverState at all, but I believe there was a
reason for it, even though I can't remember it right now...)

> In fact, they are so special that I would
> prefer if they weren't a BlockDriverState at all

On one hand I agree they are very special; I think historically there was no reason to make /dev/sg a BlockDriverState.

On the other hand, if /dev/sg were not BlockDriverStates, we would have to invent yet another polymorphic backend kind, with nontrivial code duplication between block/{raw-posix,iscsi}.c and the new kind.  So perhaps it's the worst choice except all others...

Fix included in qemu-kvm-1.5.3-53.el7

Reproduce this bug using following version:
kernel-3.10.0-99.el7.x86_64
qemu-kvm-1.5.3-48.el7.x86_64

Steps to Reproduce:
1. setup a iscsi server as comment 0
2. Boot a guest with this libiscsi disk
# /usr/libexec/qemu-kvm -M pc -enable-kvm -m 4096 -smp 4...-drive file=iscsi://10.66.9.107/iqn.2008-09.com.example:server.target2/0,if=none,id=drive-data-disk,format=raw,cache=none,aio=native -iscsi id=iqn1,user=redhat,password=redhat -device virtio-scsi-pci,id=scsi1,bus=pci.0,addr=0x7 -device scsi-hd,drive=drive-data-disk,bus=scsi1.0,id=data-disk

Actual results:
after step2, qemu-kvm core dumped as following:
qemu-kvm: block.c:850: bdrv_open_common: Assertion `bs->request_alignment != 0' failed.
Aborted (core dumped)

Verify this bug using the following version:
kernel-3.10.0-99.el7.x86_64
qemu-kvm-1.5.3-53.el7.x86_64

Steps to Verification:
1. setup a iscsi server as comment 0
2. Boot a guest with this libiscsi disk
# /usr/libexec/qemu-kvm -M pc -enable-kvm -m 4096 -smp 4...-drive file=iscsi://10.66.9.107/iqn.2008-09.com.example:server.target2/0,if=none,id=drive-data-disk,format=raw,cache=none,aio=native -iscsi id=iqn1,user=redhat,password=redhat -device virtio-scsi-pci,id=scsi1,bus=pci.0,addr=0x7 -device scsi-hd,drive=drive-data-disk,bus=scsi1.0,id=data-disk

Actual results:
after step2, qemu-kvm quits with the error info:
(qemu) qemu-kvm: -device scsi-hd,drive=drive-data-disk,bus=scsi1.0,id=data-disk: unwanted /dev/sg*
qemu-kvm: -device scsi-hd,drive=drive-data-disk,bus=scsi1.0,id=data-disk: Device initialization failed.
qemu-kvm: -device scsi-hd,drive=drive-data-disk,bus=scsi1.0,id=data-disk: Device 'scsi-hd' could not be initialized

This is the correct error message indeed. A SCSI generic device like LUN 0 of
your iscsi target can only be used with scsi-generic, not with scsi-disk.

(In reply to Kevin Wolf from comment #17)
> This is the correct error message indeed. A SCSI generic device like LUN 0 of
> your iscsi target can only be used with scsi-generic, not with scsi-disk.

Yes, thanks for your kindly reminds, both the pass-through(scsi-block) and assign(scsi-hd) LUN 0 of my iscsi target fail with a waring prompt 'unwanted /dev/sg*' if specified '/0' for it, while if specified '/1' to use LUN 1 of my target which has no such issue.

# tgt-admin --show
Target 1: iqn.2008-09.com.example:server.target2
    System information:
        Driver: iscsi
        State: ready
...
    LUN information:
        LUN: 0
            Type: controller
            SCSI ID: IET     00010000
            SCSI SN: beaf10
            Size: 0 MB, Block size: 1
            Online: Yes
            Removable media: No
            Prevent removal: No
            Readonly: No
            Backing store type: null
            Backing store path: None
            Backing store flags: 
        LUN: 1
            Type: disk
            SCSI ID: IET     00010001
            SCSI SN: beaf11
            Size: 2097 MB, Block size: 512
            Online: Yes
            Removable media: No
            Prevent removal: No
            Readonly: No
            Backing store type: rdwr
            Backing store path: /iscsi.img
            Backing store flags: 
    Account information:
        redhat
    ACL information:
        ALL

e.g1:...-drive file=iscsi://10.66.9.107/iqn.2008-09.com.example:server.target1/0,if=none,id=drive-data-disk,format=raw,cache=none,aio=native -iscsi id=iqn1,user=redhat,password=redhat -device virtio-scsi-pci,id=scsi1,bus=pci.0,addr=0x7 -device scsi-hd,drive=drive-data-disk,bus=scsi1.0,id=data-diskWarning: option deprecated, use lost_tick_policy property of kvm-pit instead.
QEMU 1.5.3 monitor - type 'help' for more information
(qemu) qemu-kvm: -device scsi-hd,drive=drive-data-disk,bus=scsi1.0,id=data-disk: unwanted /dev/sg*
qemu-kvm: -device scsi-hd,drive=drive-data-disk,bus=scsi1.0,id=data-disk: Device initialization failed.
qemu-kvm: -device scsi-hd,drive=drive-data-disk,bus=scsi1.0,id=data-disk: Device 'scsi-hd' could not be initialized

e.g2:... -drive file=iscsi://10.66.9.107/iqn.2008-09.com.example:server.target1/0,if=none,id=drive-data-disk,format=raw,cache=none,aio=native -iscsi id=iqn1,user=redhat,password=redhat -device virtio-scsi-pci,id=scsi1,bus=pci.0,addr=0x7 -device scsi-block,drive=drive-data-disk,bus=scsi1.0,id=data-disk
Warning: option deprecated, use lost_tick_policy property of kvm-pit instead.
QEMU 1.5.3 monitor - type 'help' for more information
(qemu) qemu-kvm: -device scsi-block,drive=drive-data-disk,bus=scsi1.0,id=data-disk: unwanted /dev/sg*
qemu-kvm: -device scsi-block,drive=drive-data-disk,bus=scsi1.0,id=data-disk: Device initialization failed.
qemu-kvm: -device scsi-block,drive=drive-data-disk,bus=scsi1.0,id=data-disk: Device 'scsi-block' could not be initialized

According to comment #15 and comment #17, set this issue to VERIFIED status, please correct me if any mistake, thanks.

--------------------------------------------------------------------------

But if I met another issue 'qemu-kvm: Failed to sync10 data on iSCSI lun. SENSE KEY:ILLEGAL_REQUEST(5) ASCQ:INVALID_OPERATION_CODE(0x2000)' when shutdown guest if i use scsi-generic to specified the LUN 0 of my iscsi target with '/0'. I will separate it to a new issue(bug 1078650).

(qemu) qemu-kvm: Failed to sync10 data on iSCSI lun. SENSE KEY:ILLEGAL_REQUEST(5) ASCQ:INVALID_OPERATION_CODE(0x2000)
qemu-kvm: Failed to sync10 data on iSCSI lun. SENSE KEY:ILLEGAL_REQUEST(5) ASCQ:INVALID_OPERATION_CODE(0x2000)

Best Regards,
sluo

This request was resolved in Red Hat Enterprise Linux 7.0.

Contact your manager or support representative in case you have further questions about the request.