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| author | Kevin Wolf | 2018-09-07 13:45:54 +0200 |
|---|---|---|
| committer | Kevin Wolf | 2018-09-25 15:50:15 +0200 |
| commit | 5ca9d21bd1c8eeb578d0964e31bd03d47c25773d (patch) | |
| tree | d6e46a41c6f9d223e35fc9c011bc4134ef31e67c /include | |
| parent | block-backend: Add .drained_poll callback (diff) | |
| download | qemu-5ca9d21bd1c8eeb578d0964e31bd03d47c25773d.tar.gz qemu-5ca9d21bd1c8eeb578d0964e31bd03d47c25773d.tar.xz qemu-5ca9d21bd1c8eeb578d0964e31bd03d47c25773d.zip | |
block-backend: Fix potential double blk_delete()
blk_unref() first decreases the refcount of the BlockBackend and calls
blk_delete() if the refcount reaches zero. Requests can still be in
flight at this point, they are only drained during blk_delete():
At this point, arbitrary callbacks can run. If any callback takes a
temporary BlockBackend reference, it will first increase the refcount to
1 and then decrease it to 0 again, triggering another blk_delete(). This
will cause a use-after-free crash in the outer blk_delete().
Fix it by draining the BlockBackend before decreasing to refcount to 0.
Assert in blk_ref() that it never takes the first refcount (which would
mean that the BlockBackend is already being deleted).
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'include')
0 files changed, 0 insertions, 0 deletions