Description of problem: When further debugging issue bz#1999051 , I did some write actions on a test VM to be able to simulate the issue. But while doing this. The VM crashed like 3 our of 4 times with the following message: qemu-kvm: ../util/iov.c:428: qemu_iovec_init_extended: Assertion `mid_qiov->niov <= IOV_MAX' failed. This was when running a 'dd if=/dev/zero of=test' inside the VM. It happens after a few seconds. Version-Release number of selected component (if applicable): qemu-kvm-6.0.0-26.el8s.x86_64 How reproducible: Disk is only 10GB, and almost always crashes before I could write 10G. Steps to Reproduce: 1. Create a VM with VirtIO disk 2. Run a 'dd if=/dev/zero of=test' 3. It will crash
This would seem to be related to qemu commit 4c002cef0 (https://git.qemu.org/?p=qemu.git;a=commit;h=4c002cef0e9abe7135d7916c51abce47f7fc1ee2) There is also qemu commit 87ab88025 (https://git.qemu.org/?p=qemu.git;a=commit;h=87ab88025247b893aad5071fd38301b67be76d1a) which resolves another bug in the series If you're willing to try the upstream qemu to see if it fixes things (both issues) that could be an interesting data point.
This issue should be same reason with Bug 1994494 - VM remains in paused state when trying to write on a resized disk resides on iscsi It will hit crash when using qcow2 format. https://bugzilla.redhat.com/show_bug.cgi?id=1994494#c66
*** This bug has been marked as a duplicate of bug 1994494 ***