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Date: Thu, 21 Mar 2013 11:45:35 +0100
From: Peter Lieven <pl@dlhnet.de>
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Subject: [Qemu-devel] iscsi / block segfault regression
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To: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>, ronnie sahlberg <ronniesahlberg@gmail.com>

Hi,

I currently try to debug a regression in git master with iscsi that happens with some iscsi volumes.
I added debugging output to all aio calls into block/iscsi.c and it seems that immediately after
brdv_open something is overwriting bs->opaque with a new pointer.

~/git/qemu$ x86_64-softmmu/qemu-system-x86_64 -k de -enable-kvm -m 1024 -drive format=iscsi,file=iscsi://172.21.200.31/iqn.2001-05.com.equallogic:0-8a0906-3c0f4e007-dce91829d0450add-lieven-storage-migration-test-hd0/0,if=virtio,cache=writeback,aio=native 
  -vnc :1 -boot dc -monitor stdio
iscsi open start
iscsi_full_connect_sync: iscsilun = 140063347224208, iscsilun->iscsi = 140063347225536, bs = 140063347221696, filename=iscsi://172.21.200.31/iqn.2001-05.com.equallogic:0-8a0906-3c0f4e007-dce91829d0450add-lieven-storage-migration-test-hd0/0
iscsi open finish ret=0
iscsi_aio_flush: iscsilun = 140063347230736, iscsilun->iscsi = 0, bs = 140063347221696, filename=iscsi://172.21.200.31/iqn.2001-05.com.equallogic:0-8a0906-3c0f4e007-dce91829d0450add-lieven-storage-migration-test-hd0/0
iscsi_aio_flush_acb: iscsilun = 140063347230736, iscsilun->iscsi = 0, bs = 140063347221696, filename=iscsi://172.21.200.31/iqn.2001-05.com.equallogic:0-8a0906-3c0f4e007-dce91829d0450add-lieven-storage-migration-test-hd0/0
Speicherzugriffsfehler (Speicherabzug geschrieben)

bs address is unchanged, but iscsilun address is changed after connection it seems to an area with zeroed memory. the pointer to the iscsi context
is thus NULL.

iscsilun, iscsilun->iscsi and bs are addresses.

Peter