Re: [PATCH 1/5] md: Flush workqueue md_rdev_misc_wq in md_alloc()

[Song Liu]

On Thu, Aug 11, 2022 at 10:14 AM Logan Gunthorpe <logang@xxxxxxxxxxxx> wrote:
>
> From: David Sloan <david.sloan@xxxxxxxxxxxxx>
>
> A race condition still exists when removing and re-creating md devices
> in test cases. However, it is only seen on some setups.
>
> The race condition was tracked down to a reference still being held
> to the kobject by the rdev in the md_rdev_misc_wq which will be released
> in rdev_delayed_delete().
>
> md_alloc() waits for previous deletions by waiting on the md_misc_wq,
> but the md_rdev_misc_wq may still be holding a reference to a recently
> removed device.
>
> To fix this, also flush the md_rdev_misc_wq in md_alloc().
>
> Signed-off-by: David Sloan <david.sloan@xxxxxxxxxxxxx>
> [logang@xxxxxxxxxxxx: rewrote commit message]
> Signed-off-by: Logan Gunthorpe <logang@xxxxxxxxxxxx>

Applied 1/5 to md-fixes.

Thanks!
Song