Re: [PATCH] block/block-backend: blk_set_enable_write_cache is IO_CODE

[Kevin Wolf <kwolf@redhat.com>]

Am 27.10.2022 um 09:27 hat Emanuele Giuseppe Esposito geschrieben:
> blk_set_enable_write_cache() is defined as GLOBAL_STATE_CODE
> but can be invoked from iothreads when handling scsi requests.
> This triggers an assertion failure:
> 
>  0x00007fd6c3515ce1 in raise () from /lib/x86_64-linux-gnu/libc.so.6
>  0x00007fd6c34ff537 in abort () from /lib/x86_64-linux-gnu/libc.so.6
>  0x00007fd6c34ff40f in ?? () from /lib/x86_64-linux-gnu/libc.so.6
>  0x00007fd6c350e662 in __assert_fail () from /lib/x86_64-linux-gnu/libc.so.6
>  0x000056149e2cea03 in blk_set_enable_write_cache (wce=true, blk=0x5614a01c27f0)
>    at ../src/block/block-backend.c:1949
>  0x000056149e2d0a67 in blk_set_enable_write_cache (blk=0x5614a01c27f0,
>    wce=<optimized out>) at ../src/block/block-backend.c:1951
>  0x000056149dfe9c59 in scsi_disk_apply_mode_select (p=0x7fd6b400c00e "\004",
>    page=<optimized out>, s=<optimized out>) at ../src/hw/scsi/scsi-disk.c:1520
>  mode_select_pages (change=true, len=18, p=0x7fd6b400c00e "\004", r=0x7fd6b4001ff0)
>    at ../src/hw/scsi/scsi-disk.c:1570
>  scsi_disk_emulate_mode_select (inbuf=<optimized out>, r=0x7fd6b4001ff0) at
>    ../src/hw/scsi/scsi-disk.c:1640
>  scsi_disk_emulate_write_data (req=0x7fd6b4001ff0) at ../src/hw/scsi/scsi-disk.c:1934
>  0x000056149e18ff16 in virtio_scsi_handle_cmd_req_submit (req=<optimized out>,
>    req=<optimized out>, s=0x5614a12f16b0) at ../src/hw/scsi/virtio-scsi.c:719
>  virtio_scsi_handle_cmd_vq (vq=0x7fd6bab92140, s=0x5614a12f16b0) at
>    ../src/hw/scsi/virtio-scsi.c:761
>  virtio_scsi_handle_cmd (vq=<optimized out>, vdev=<optimized out>) at
>    ../src/hw/scsi/virtio-scsi.c:775
>  virtio_scsi_handle_cmd (vdev=0x5614a12f16b0, vq=0x7fd6bab92140) at
>    ../src/hw/scsi/virtio-scsi.c:765
>  0x000056149e1a8aa6 in virtio_queue_notify_vq (vq=0x7fd6bab92140) at
>    ../src/hw/virtio/virtio.c:2365
>  0x000056149e3ccea5 in aio_dispatch_handler (ctx=ctx@entry=0x5614a01babe0,
>    node=<optimized out>) at ../src/util/aio-posix.c:369
>  0x000056149e3cd868 in aio_dispatch_ready_handlers (ready_list=0x7fd6c09b2680,
>    ctx=0x5614a01babe0) at ../src/util/aio-posix.c:399
>  aio_poll (ctx=0x5614a01babe0, blocking=blocking@entry=true) at
>    ../src/util/aio-posix.c:713
>  0x000056149e2a7796 in iothread_run (opaque=opaque@entry=0x56149ffde500) at
>    ../src/iothread.c:67
>  0x000056149e3d0859 in qemu_thread_start (args=0x7fd6c09b26f0) at
>    ../src/util/qemu-thread-posix.c:504
>  0x00007fd6c36b9ea7 in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
>  0x00007fd6c35d9aef in clone () from /lib/x86_64-linux-gnu/libc.so.6
> 
> Changing GLOBAL_STATE_CODE in IO_CODE is allowed, since GSC callers are
> allowed to call IO_CODE.
> 
> Resolves: #1272
> 
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>

Thanks, applied to the block branch.

Kevin