XPost: linux.debian.bugs.dist, linux.kernel   
   From: axboe@kernel.dk   
      
   On 10/13/25 11:47 AM, Salvatore Bonaccorso wrote:   
   > Hi Jens,   
   >   
   > Kevin Lumik reported in Debian the following issue (not exactly a   
   > minimal reproducer, but bisection results follows):   
   >   
   > On Fri, Sep 26, 2025 at 10:34:22AM +0300, Kevin Lumik wrote:   
   >   
   >> Dear Maintainer,   
   >>   
   >> After upgrading from Debian Bookworm to Trixie, an issue within KVM guests   
   when creating an LVM snapshot of its volume   
   >> has surfaced. When a LVM snapshot is taken from the host, the guest starts   
   to get I/O errors. The issue seems to only   
   >> appear when aio=io_uring is specified in the KVM drive parameters and also   
   seems to resolve when downgrading the kernel   
   >> package down to 6.1. The issue is also not reproducible when using   
   aio=native.   
   >>   
   >> KVM args for the drive: "-drive id=drive-   
   >> virtio0,format=raw,file=/dev/dom/vps_testsql,cache=none,aio=i   
   _uring,index=0,media=disk,if=virtio"   
   >>   
   >> An IO workload is being created in the VM using "fio --randrepeat=1   
   --ioengine=io_uring --direct=1 --gtod_reduce=1 --   
   >> name=randwrite --filename=/root/test.bin --bs=4k --iodepth=64 --runtime=60   
   --numjobs=32 --readwrite=randwrite --size=1G   
   >> --rwmixread=75 --group_reporting"   
   >>   
   >> After running "lvcreate -s /dev/dom/vps_testsql -n test -L 1G" on the host   
   we can observe fio erroring out:   
   >>   
   >> ...   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=46977024, buflen=4096   
   >> fio: pid=7367, err=5/file:io_u.c:1876, func=io_u error, error=Input/output   
   error   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=261505024, buflen=4096   
   >> fio: pid=7374, err=5/file:io_u.c:1876, func=io_u error, error=Input/output   
   error   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=973840384, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=9637888, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=159965184, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=857505792, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=90787840, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=26427392, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=955621376, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=96169984, buflen=4096   
   >> fio: pid=7372, err=5/file:io_u.c:1876, func=io_u error, error=Input/output   
   error   
   >> fio: pid=7362, err=5/file:io_u.c:1876, func=io_u error, error=Input/output   
   error   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=203702272, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=814649344, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=91467776, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=948256768, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=105295872, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=75247616, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=1062293504, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=111955968, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=942563328, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=117354496, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=1050402816, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=125419520, buflen=4096   
   >> fio: io_u error on file /root/test.bin: Input/output error: write   
   offset=129044480, buflen=4096   
   >> fio: pid=7369, err=5/file:io_u.c:1876, func=io_u error, error=Input/output   
   error   
   >> fio: pid=7373, err=5/file:io_u.c:1876, func=io_u error, error=Input/output   
   error   
   >> fio: pid=7348, err=5/file:io_u.c:1876, func=io_u error, error=Input/output   
   error   
   >> fio: pid=7375, err=5/file:io_u.c:1876, func=io_u error, error=Input/output   
   error   
   >> fio: pid=7358, err=5/file:io_u.c:1876, func=io_u error, error=Input/output   
   error   
   >> fio: pid=7359, err=5/file:io_u.c:1876, func=io_u error, error=Input/output   
   error   
   >>   
   >> randwrite: (groupid=0, jobs=32): err= 5 (file:io_u.c:1876, func=io_u error,   
   error=Input/output error): pid=7344: Thu Sep   
   >> 25 16:28:30 2025   
   >>   write: IOPS=194k, BW=758MiB/s (795MB/s)(3976MiB/5244msec); 0 zone resets   
      
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