Re: [PATCH] block/nfs: Do not enter coroutine from CB

[Kevin Wolf <kwolf@redhat.com>]

Am 02.01.2026 um 16:32 hat Hanna Czenczek geschrieben:
> The reasoning I gave for why it would be safe to call aio_co_wake()
> despite holding the mutex was wrong: It is true that the current request
> will not re-acquire the mutex, but a subsequent request in the same
> coroutine can.  Because the mutex is a non-coroutine mutex, this will
> result in a deadlock.
> 
> Therefore, we must either not enter the coroutine here (only scheduling
> it), or release the mutex around aio_co_wake().  I opt for the former,
> as it is the behavior prior to the offending commit, and so seems safe
> to do.
> 
> Fixes: deb35c129b859b9bec70fd42f856a0b7c1dc6e61
>        ("nfs: Run co BH CB in the coroutine’s AioContext")
> Buglink: https://gitlab.com/qemu-project/qemu/-/issues/2622#note_2965097035
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Hanna Czenczek <hreitz@redhat.com>

Thanks, applied to the block branch.

Kevin