bdrv_*() APIs expect a valid BlockDriverState. Calling them with bs=NULL
leads to undefined behavior.
Jonathan Cameron reported this following NULL pointer dereference when a
VM with a virtio-blk device and a memory-backend-file object is
terminated:
1. qemu_cleanup() closes all drives, setting blk->root to NULL
2. qemu_cleanup() calls user_creatable_cleanup(), which results in a RAM
block notifier callback because the memory-backend-file is destroyed.
3. blk_unregister_buf() is called by virtio-blk's BlockRamRegistrar
notifier callback and undefined behavior occurs.
Fixes: baf422684d ("virtio-blk: use BDRV_REQ_REGISTERED_BUF optimization hint")
Co-authored-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20221121211923.1993171-1-stefanha@redhat.com>
blk_get_aio_context() asserts that blk->ctx is always equal to the root
BDS's context (if there is a root BDS). Therefore,
blk_do_set_aio_context() must update blk->ctx immediately after the root
BDS's context has changed.
Without this patch, the next patch would break iotest 238, because
bdrv_drained_begin() (called by blk_do_set_aio_context()) may then
invoke bdrv_child_get_parent_aio_context() on the root child, i.e.
blk_get_aio_context(). However, by this point, blk->ctx would not have
been updated and thus differ from the root node's context. This patch
fixes that.
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20221107151321.211175-3-hreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We want to use bdrv_child_get_parent_aio_context() from
bdrv_parent_drained_{begin,end}_single(), both of which are "I/O or GS"
functions.
Prior to 3ed4f708fe, all the implementations were I/O code anyway.
3ed4f708fe has put block jobs' AioContext field under the job mutex, so
to make child_job_get_parent_aio_context() work in an I/O context, we
need to take that lock there.
Furthermore, blk_root_get_parent_aio_context() is not marked as
anything, but is safe to run in an I/O context, so mark it that way now.
(blk_get_aio_context() is an I/O code function.)
With that done, all implementations explicitly are I/O code, so we can
mark bdrv_child_get_parent_aio_context() as I/O code, too, so callers
know it is safe to run from both GS and I/O contexts.
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20221107151321.211175-2-hreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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>
Message-Id: <20221027072726.2681500-1-eesposit@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Tested-by: Antoine Damhet <antoine.damhet@shadow.tech>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
No functional changes intended.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20221025084952.2139888-10-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Together with all _can_set_ and _set_ APIs, as they are not needed
anymore.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20221025084952.2139888-9-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Replace all direct usage of ->can_set_aio_ctx and ->set_aio_ctx,
and call bdrv_child_try_change_aio_context() in
bdrv_try_set_aio_context(), the main function called through
the whole block layer.
From this point onwards, ->can_set_aio_ctx and ->set_aio_ctx
won't be used anymore.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20221025084952.2139888-8-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
blk_root_change_aio_ctx() is very similar to blk_root_can_set_aio_ctx(),
but implements a new transaction so that if all check pass, the new
transaction's .commit will take care of changing the BlockBackend
AioContext. blk_root_set_aio_ctx_commit() is the same as
blk_root_set_aio_ctx().
Note: bdrv_child_try_change_aio_context() is not called by
anyone at this point.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20221025084952.2139888-7-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Registering an I/O buffer is only a performance optimization hint but it
is still necessary to return errors when it fails.
Later patches will need to detect errors when registering buffers but an
immediate advantage is that error_report() calls are no longer needed in
block driver .bdrv_register_buf() functions.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20221013185908.1297568-8-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The only implementor of bdrv_register_buf() is block/nvme.c, where the
size is not needed when unregistering a buffer. This is because
util/vfio-helpers.c can look up mappings by address.
Future block drivers that implement bdrv_register_buf() may not be able
to do their job given only the buffer address. Add a size argument to
bdrv_unregister_buf().
Also document the assumptions about
bdrv_register_buf()/bdrv_unregister_buf() calls. The same <host, size>
values that were given to bdrv_register_buf() must be given to
bdrv_unregister_buf().
gcc 11.2.1 emits a spurious warning that img_bench()'s buf_size local
variable might be uninitialized, so it's necessary to silence the
compiler.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Message-id: 20221013185908.1297568-5-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Callers of coroutine_fn must be coroutine_fn themselves, or the call
must be within "if (qemu_in_coroutine())". Apply coroutine_fn to
functions where this holds.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220922084924.201610-3-pbonzini@redhat.com>
[kwolf: Fixed up coding style]
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Some can be made static, others are unused generated_co_wrappers.
Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220705161527.1054072-19-afaria@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Keep generated_co_wrapper and coroutine_fn pairs together. This should
make it clear that each I/O function has these two versions.
Also move blk_co_{pread,pwrite}()'s implementations out of the header
file for consistency.
Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220705161527.1054072-18-afaria@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Also convert blk_truncate() into a generated_co_wrapper.
Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220705161527.1054072-17-afaria@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Also convert blk_ioctl() into a generated_co_wrapper.
Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220705161527.1054072-16-afaria@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220705161527.1054072-15-afaria@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220705161527.1054072-14-afaria@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220705161527.1054072-13-afaria@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Also convert blk_pwrite_compressed() into a generated_co_wrapper.
Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220705161527.1054072-12-afaria@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Swap 'buf' and 'bytes' around for consistency with other I/O functions.
Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220705161527.1054072-11-afaria@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Also convert it into a generated_co_wrapper.
Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220705161527.1054072-10-afaria@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Implement blk_preadv_part() using generated_co_wrapper.
Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220705161527.1054072-9-afaria@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
We need to add include/sysemu/block-backend-io.h to the inputs of the
block-gen.c target defined in block/meson.build.
Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220705161527.1054072-7-afaria@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
For consistency with other I/O functions, and in preparation to
implement them using generated_co_wrapper.
Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220705161527.1054072-5-afaria@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Swap 'buf' and 'bytes' around for consistency with
blk_co_{pread,pwrite}(), and in preparation to implement these functions
using generated_co_wrapper.
Callers were updated using this Coccinelle script:
@@ expression blk, offset, buf, bytes, flags; @@
- blk_pread(blk, offset, buf, bytes, flags)
+ blk_pread(blk, offset, bytes, buf, flags)
@@ expression blk, offset, buf, bytes, flags; @@
- blk_pwrite(blk, offset, buf, bytes, flags)
+ blk_pwrite(blk, offset, bytes, buf, flags)
It had no effect on hw/block/nand.c, presumably due to the #if, so that
file was updated manually.
Overly-long lines were then fixed by hand.
Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220705161527.1054072-4-afaria@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
For consistency with other I/O functions, and in preparation to
implement it using generated_co_wrapper.
Callers were updated using this Coccinelle script:
@@ expression blk, offset, buf, bytes; @@
- blk_pread(blk, offset, buf, bytes)
+ blk_pread(blk, offset, buf, bytes, 0)
It had no effect on hw/block/nand.c, presumably due to the #if, so that
file was updated manually.
Overly-long lines were then fixed by hand.
Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220705161527.1054072-3-afaria@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
They currently return the value of their 'bytes' parameter on success.
Make them return 0 instead, for consistency with other I/O functions and
in preparation to implement them using generated_co_wrapper. This also
makes it clear that short reads/writes are not possible.
Signed-off-by: Alberto Faria <afaria@redhat.com>
Message-Id: <20220705161527.1054072-2-afaria@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
This supports passing NULL ops to blk_set_dev_ops()
so that we can remove stale ops in some cases.
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20220523084611.91-2-xieyongji@bytedance.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Commit 1b7fd72955 ("block: rename buffer_alignment to
guest_block_size") noted:
At this point, the field is set by the device emulation, but completely
ignored by the block layer.
The last time the value of buffer_alignment/guest_block_size was
actually used was before commit 339064d506 ("block: Don't use guest
sector size for qemu_blockalign()").
This value has not been used since 2013. Get rid of it.
Cc: Xie Yongji <xieyongji@bytedance.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20220518130945.2657905-1-stefanha@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Faria <afaria@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block coroutines functions run in different aiocontext, and are
not protected by the BQL. Therefore are I/O.
On the other side, generated_co_wrapper functions use BDRV_POLL_WHILE,
meaning the caller can either be the main loop or a specific iothread.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20220303151616.325444-25-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20220303151616.325444-22-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Following the assertion derived from the API split,
propagate the assertion also in the static functions.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20220303151616.325444-18-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Mark all I/O functions with IO_CODE, and all "I/O OR GS" with
IO_OR_GS_CODE.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20220303151616.325444-14-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20220303151616.325444-13-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Mark all I/O functions with IO_CODE, and all "I/O OR GS" with
IO_OR_GS_CODE.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20220303151616.325444-10-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
All the global state (GS) API functions will check that
qemu_in_main_thread() returns true. If not, it means
that the safety of BQL cannot be guaranteed, and
they need to be moved to I/O.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20220303151616.325444-9-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Similarly to the previous patches, split block-backend.h
in block-backend-io.h and block-backend-global-state.h
In addition, remove "block/block.h" include as it seems
it is not necessary anymore, together with "qemu/iov.h"
block-backend-common.h contains the structures shared between
the two headers, and the functions that can't be categorized as
I/O or global state.
Assertions are added in the next patch.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20220303151616.325444-8-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Following the bdrv_activate renaming, change also the name
of the respective callers.
bdrv_invalidate_cache_all -> bdrv_activate_all
blk_invalidate_cache -> blk_activate
test_sync_op_invalidate_cache -> test_sync_op_activate
No functional change intended.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220209105452.1694545-5-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This function is currently just a wrapper for bdrv_invalidate_cache(),
but in future will contain the code of bdrv_co_invalidate_cache() that
has to always be protected by BQL, and leave the rest in the I/O
coroutine.
Replace all bdrv_invalidate_cache() invokations with bdrv_activate().
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220209105452.1694545-4-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
After migration, the permissions the guest device wants to impose on its
BlockBackend are stored in blk->perm and blk->shared_perm. In
blk_root_activate(), we take our permissions, but keep all shared
permissions open by calling `blk_set_perm(blk->perm, BLK_PERM_ALL)`.
Only afterwards (immediately or later, depending on the runstate) do we
restrict the shared permissions by calling
`blk_set_perm(blk->perm, blk->shared_perm)`. Unfortunately, our first
call with shared_perm=BLK_PERM_ALL has overwritten blk->shared_perm to
be BLK_PERM_ALL, so this is a no-op and the set of shared permissions is
not restricted.
Fix this bug by saving the set of shared permissions before invoking
blk_set_perm() with BLK_PERM_ALL and restoring it afterwards.
Fixes: 5f7772c4d0
("block-backend: Defer shared_perm tightening migration
completion")
Reported-by: Peng Liang <liangpeng10@huawei.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20211125135317.186576-2-hreitz@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Peng Liang <liangpeng10@huawei.com>
The BlockBackend root child can change when aio_poll() is invoked. This
happens when a temporary filter node is removed upon blockjob
completion, for example.
Functions in block/block-backend.c must be aware of this when using a
blk_bs() pointer across aio_poll() because the BlockDriverState refcnt
may reach 0, resulting in a stale pointer.
One example is scsi_device_purge_requests(), which calls blk_drain() to
wait for in-flight requests to cancel. If the backup blockjob is active,
then the BlockBackend root child is a temporary filter BDS owned by the
blockjob. The blockjob can complete during bdrv_drained_begin() and the
last reference to the BDS is released when the temporary filter node is
removed. This results in a use-after-free when blk_drain() calls
bdrv_drained_end(bs) on the dangling pointer.
Explicitly hold a reference to bs across block APIs that invoke
aio_poll().
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2021778
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2036178
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20220111153613.25453-2-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Similarly to e7e588d432, there is a
warning in block/block-backend.c that qiov->size <= INT64_MAX is always
true on machines where size_t is narrower than a uint64_t. In said
commit, we silenced this warning by casting to uint64_t.
The commit introducing this warning here
(a93d81c84a) anticipated it and so tried
to address it the same way. However, it only did so in one of two
places where this comparison occurs, and so we still need to fix up the
other one.
Fixes: a93d81c84a
("block-backend: convert blk_aio_ functions to int64_t bytes
paramter")
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20211026090745.30800-1-hreitz@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
blk_check_bytes_request is called from blk_co_do_preadv,
blk_co_do_pwritev_part, blk_co_do_pdiscard and blk_co_copy_range
before (maybe) calling throttle_group_co_io_limits_intercept() (which
has int64_t argument) and then calling corresponding bdrv_co_ function.
bdrv_co_ functions are OK with int64_t bytes as well.
So dropping the check for INT_MAX we just get same restrictions as in
bdrv_ layer: discard and write-zeroes goes through
bdrv_check_qiov_request() and are allowed to be 64bit. Other requests
go through bdrv_check_request32() and still restricted by INT_MAX
boundary.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20211006131718.214235-13-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
To be consistent with declarations in include/sysemu/block-backend.h.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20211006131718.214235-12-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
1. Convert bytes in BlkAioEmAIOCB:
aio->bytes is only passed to already int64_t interfaces, and set in
blk_aio_prwv, which is updated here.
2. For all updated functions the parameter type becomes wider so callers
are safe.
3. In blk_aio_prwv we only store bytes to BlkAioEmAIOCB, which is
updated here.
4. Other updated functions are wrappers on blk_aio_prwv.
Note that blk_aio_preadv and blk_aio_pwritev become safer: before this
commit, it's theoretically possible to pass qiov with size exceeding
INT_MAX, which than converted to int argument of blk_aio_prwv. Now it's
converted to int64_t which is a lot better. Still add assertions.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20211006131718.214235-11-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: tweak assertion and grammar]
Signed-off-by: Eric Blake <eblake@redhat.com>
Function is updated so that parameter type becomes wider, so all
callers should be OK with it.
Look at blk_co_copy_range() itself: bytes is passed only to
blk_check_byte_request() and bdrv_co_copy_range(), which already have
int64_t bytes parameter, so we are OK.
Note that requests exceeding INT_MAX are still restricted by
blk_check_byte_request().
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20211006131718.214235-10-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: grammar tweaks]
Signed-off-by: Eric Blake <eblake@redhat.com>
Convert blk_pdiscard, blk_pwrite_compressed, blk_pwrite_zeroes.
These are just wrappers for functions with int64_t argument, so allow
passing int64_t as well. Parameter type becomes wider so all callers
should be OK with it.
Note that requests exceeding INT_MAX are still restricted by
blk_check_byte_request().
Note also that we don't (and are not going to) convert blk_pwrite and
blk_pread: these functions return number of bytes on success, so to
update them, we should change return type to int64_t as well, which
will lead to investigating and updating all callers which is too much.
So, blk_pread and blk_pwrite remain unchanged.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20211006131718.214235-9-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: grammar tweaks]
Signed-off-by: Eric Blake <eblake@redhat.com>
Let's drop hand-made coroutine wrappers and use coroutine wrapper
generation like in block/io.c.
Now, blk_foo() functions are written in same way as blk_co_foo() ones,
but wrap blk_do_foo() instead of blk_co_do_foo().
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20211006131718.214235-8-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: spelling fix]
Signed-off-by: Eric Blake <eblake@redhat.com>
This is a preparation to the following commit, to use automatic
coroutine wrapper generation.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20211006131718.214235-6-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
