| Message ID | 20230208111148.1040083-1-eesposit@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | virtio-blk: add missing AioContext lock | expand |
Dne 08. 02. 23 v 12:11 Emanuele Giuseppe Esposito napsal(a): > virtio_blk_update_config() calls blk_get_geometry and blk_getlength, > and both functions eventually end up calling bdrv_poll_co when not > running in a coroutine: > - blk_getlength is a co_wrapper_mixed function > - blk_get_geometry calls bdrv_get_geometry -> bdrv_nb_sectors, a > co_wrapper_mixed function too > > Since we are not running in a coroutine, we need to take s->blk > AioContext lock, otherwise bdrv_poll_co will inevitably call > AIO_WAIT_WHILE and therefore try to un unlock() an AioContext lock > that was never acquired. > > RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=2167838 > > Steps to reproduce the issue: simply boot a VM with > -object '{"qom-type":"iothread","id":"iothread1"}' \ > -blockdev '{"driver":"file","filename":"$QCOW2","aio":"native","node-name":"libvirt-1-storage","cache":{"direct":true,"no-flush":false},"auto-read-only":true,"discard":"unmap"}' \ > -blockdev '{"node-name":"libvirt-1-format","read-only":false,"cache":{"direct":true,"no-flush":false},"driver":"qcow2","file":"libvirt-1-storage"}' \ > -device virtio-blk-pci,iothread=iothread1,drive=libvirt-1-format,id=virtio-disk0,bootindex=1,write-cache=on > > and observe that it will fail not manage to boot with "qemu_mutex_unlock_impl: Operation not permitted" > > Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> > --- > hw/block/virtio-blk.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c > index 1762517878..cefca93b31 100644 > --- a/hw/block/virtio-blk.c > +++ b/hw/block/virtio-blk.c > @@ -894,6 +894,10 @@ static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config) > uint64_t capacity; > int64_t length; > int blk_size = conf->logical_block_size; > + AioContext *ctx; > + > + ctx = blk_get_aio_context(s->blk); > + aio_context_acquire(ctx); > > blk_get_geometry(s->blk, &capacity); > memset(&blkcfg, 0, sizeof(blkcfg)); > @@ -917,6 +921,7 @@ static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config) > * per track (cylinder). > */ > length = blk_getlength(s->blk); > + aio_context_release(ctx); > if (length > 0 && length / conf->heads / conf->secs % blk_size) { > blkcfg.geometry.sectors = conf->secs & ~s->sector_mask; > } else { Thanks, I can't talk about the correctness of the code but function-wise it addresses the issue. Tested-by: Lukáš Doktor <ldoktor@redhat.com>
On Wed, Feb 08, 2023 at 06:11:48AM -0500, Emanuele Giuseppe Esposito wrote: > virtio_blk_update_config() calls blk_get_geometry and blk_getlength, > and both functions eventually end up calling bdrv_poll_co when not > running in a coroutine: > - blk_getlength is a co_wrapper_mixed function > - blk_get_geometry calls bdrv_get_geometry -> bdrv_nb_sectors, a > co_wrapper_mixed function too > > Since we are not running in a coroutine, we need to take s->blk > AioContext lock, otherwise bdrv_poll_co will inevitably call > AIO_WAIT_WHILE and therefore try to un unlock() an AioContext lock > that was never acquired. > > RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=2167838 > > Steps to reproduce the issue: simply boot a VM with > -object '{"qom-type":"iothread","id":"iothread1"}' \ > -blockdev '{"driver":"file","filename":"$QCOW2","aio":"native","node-name":"libvirt-1-storage","cache":{"direct":true,"no-flush":false},"auto-read-only":true,"discard":"unmap"}' \ > -blockdev '{"node-name":"libvirt-1-format","read-only":false,"cache":{"direct":true,"no-flush":false},"driver":"qcow2","file":"libvirt-1-storage"}' \ > -device virtio-blk-pci,iothread=iothread1,drive=libvirt-1-format,id=virtio-disk0,bootindex=1,write-cache=on > > and observe that it will fail not manage to boot with "qemu_mutex_unlock_impl: Operation not permitted" > > Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> looks reasonable Acked-by: Michael S. Tsirkin <mst@redhat.com> merge in block tree pls. > --- > hw/block/virtio-blk.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c > index 1762517878..cefca93b31 100644 > --- a/hw/block/virtio-blk.c > +++ b/hw/block/virtio-blk.c > @@ -894,6 +894,10 @@ static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config) > uint64_t capacity; > int64_t length; > int blk_size = conf->logical_block_size; > + AioContext *ctx; > + > + ctx = blk_get_aio_context(s->blk); > + aio_context_acquire(ctx); > > blk_get_geometry(s->blk, &capacity); > memset(&blkcfg, 0, sizeof(blkcfg)); > @@ -917,6 +921,7 @@ static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config) > * per track (cylinder). > */ > length = blk_getlength(s->blk); > + aio_context_release(ctx); > if (length > 0 && length / conf->heads / conf->secs % blk_size) { > blkcfg.geometry.sectors = conf->secs & ~s->sector_mask; > } else { > -- > 2.39.1
On Wed, Feb 08, 2023 at 06:11:48AM -0500, Emanuele Giuseppe Esposito wrote: > virtio_blk_update_config() calls blk_get_geometry and blk_getlength, > and both functions eventually end up calling bdrv_poll_co when not > running in a coroutine: > - blk_getlength is a co_wrapper_mixed function > - blk_get_geometry calls bdrv_get_geometry -> bdrv_nb_sectors, a > co_wrapper_mixed function too > > Since we are not running in a coroutine, we need to take s->blk > AioContext lock, otherwise bdrv_poll_co will inevitably call > AIO_WAIT_WHILE and therefore try to un unlock() an AioContext lock > that was never acquired. > > RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=2167838 > > Steps to reproduce the issue: simply boot a VM with > -object '{"qom-type":"iothread","id":"iothread1"}' \ > -blockdev '{"driver":"file","filename":"$QCOW2","aio":"native","node-name":"libvirt-1-storage","cache":{"direct":true,"no-flush":false},"auto-read-only":true,"discard":"unmap"}' \ > -blockdev '{"node-name":"libvirt-1-format","read-only":false,"cache":{"direct":true,"no-flush":false},"driver":"qcow2","file":"libvirt-1-storage"}' \ > -device virtio-blk-pci,iothread=iothread1,drive=libvirt-1-format,id=virtio-disk0,bootindex=1,write-cache=on > > and observe that it will fail not manage to boot with "qemu_mutex_unlock_impl: Operation not permitted" > > Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> > --- > hw/block/virtio-blk.c | 5 +++++ > 1 file changed, 5 insertions(+) Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
On Wed, Feb 08, 2023 at 06:11:48AM -0500, Emanuele Giuseppe Esposito wrote: > virtio_blk_update_config() calls blk_get_geometry and blk_getlength, > and both functions eventually end up calling bdrv_poll_co when not > running in a coroutine: > - blk_getlength is a co_wrapper_mixed function > - blk_get_geometry calls bdrv_get_geometry -> bdrv_nb_sectors, a > co_wrapper_mixed function too > > Since we are not running in a coroutine, we need to take s->blk > AioContext lock, otherwise bdrv_poll_co will inevitably call > AIO_WAIT_WHILE and therefore try to un unlock() an AioContext lock > that was never acquired. > > RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=2167838 > > Steps to reproduce the issue: simply boot a VM with > -object '{"qom-type":"iothread","id":"iothread1"}' \ > -blockdev '{"driver":"file","filename":"$QCOW2","aio":"native","node-name":"libvirt-1-storage","cache":{"direct":true,"no-flush":false},"auto-read-only":true,"discard":"unmap"}' \ > -blockdev '{"node-name":"libvirt-1-format","read-only":false,"cache":{"direct":true,"no-flush":false},"driver":"qcow2","file":"libvirt-1-storage"}' \ > -device virtio-blk-pci,iothread=iothread1,drive=libvirt-1-format,id=virtio-disk0,bootindex=1,write-cache=on > > and observe that it will fail not manage to boot with "qemu_mutex_unlock_impl: Operation not permitted" > > Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> > --- > hw/block/virtio-blk.c | 5 +++++ > 1 file changed, 5 insertions(+) Thanks, applied to my block tree: https://gitlab.com/stefanha/qemu/commits/block Stefan
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index 1762517878..cefca93b31 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -894,6 +894,10 @@ static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config) uint64_t capacity; int64_t length; int blk_size = conf->logical_block_size; + AioContext *ctx; + + ctx = blk_get_aio_context(s->blk); + aio_context_acquire(ctx); blk_get_geometry(s->blk, &capacity); memset(&blkcfg, 0, sizeof(blkcfg)); @@ -917,6 +921,7 @@ static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config) * per track (cylinder). */ length = blk_getlength(s->blk); + aio_context_release(ctx); if (length > 0 && length / conf->heads / conf->secs % blk_size) { blkcfg.geometry.sectors = conf->secs & ~s->sector_mask; } else {
virtio_blk_update_config() calls blk_get_geometry and blk_getlength, and both functions eventually end up calling bdrv_poll_co when not running in a coroutine: - blk_getlength is a co_wrapper_mixed function - blk_get_geometry calls bdrv_get_geometry -> bdrv_nb_sectors, a co_wrapper_mixed function too Since we are not running in a coroutine, we need to take s->blk AioContext lock, otherwise bdrv_poll_co will inevitably call AIO_WAIT_WHILE and therefore try to un unlock() an AioContext lock that was never acquired. RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=2167838 Steps to reproduce the issue: simply boot a VM with -object '{"qom-type":"iothread","id":"iothread1"}' \ -blockdev '{"driver":"file","filename":"$QCOW2","aio":"native","node-name":"libvirt-1-storage","cache":{"direct":true,"no-flush":false},"auto-read-only":true,"discard":"unmap"}' \ -blockdev '{"node-name":"libvirt-1-format","read-only":false,"cache":{"direct":true,"no-flush":false},"driver":"qcow2","file":"libvirt-1-storage"}' \ -device virtio-blk-pci,iothread=iothread1,drive=libvirt-1-format,id=virtio-disk0,bootindex=1,write-cache=on and observe that it will fail not manage to boot with "qemu_mutex_unlock_impl: Operation not permitted" Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> --- hw/block/virtio-blk.c | 5 +++++ 1 file changed, 5 insertions(+)