On Wed, Jun 29, 2022 at 12:29 AM David Hildenbrand <da...@redhat.com> wrote:
> On 06.05.22 18:31, Tong Zhang wrote:
> > assert(dbs->acb) is meant to check the return value of io_func per
> > documented in commit 6bee44ea34 ("dma: the passed io_func does not
> > return NULL"). However, there is a chance that after calling
> > aio_context_release(dbs->ctx); the dma_blk_cb function is called before
> > the assertion and dbs->acb is set to NULL again at line 121. Thus when
> > we run assert at line 181 it will fail.
> >
> > softmmu/dma-helpers.c:181: dma_blk_cb: Assertion `dbs->acb' failed.
> >
> > Reported-by: Francisco Londono <f.lond...@samsung.com>
> > Signed-off-by: Tong Zhang <t.zha...@samsung.com>
> > ---
> > softmmu/dma-helpers.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/softmmu/dma-helpers.c b/softmmu/dma-helpers.c
> > index 7820fec54c..cb81017928 100644
> > --- a/softmmu/dma-helpers.c
> > +++ b/softmmu/dma-helpers.c
> > @@ -177,8 +177,8 @@ static void dma_blk_cb(void *opaque, int ret)
> > aio_context_acquire(dbs->ctx);
> > dbs->acb = dbs->io_func(dbs->offset, &dbs->iov,
> > dma_blk_cb, dbs, dbs->io_func_opaque);
> > - aio_context_release(dbs->ctx);
> > assert(dbs->acb);
> > + aio_context_release(dbs->ctx);
> > }
> >
> > static void dma_aio_cancel(BlockAIOCB *acb)
>
> Please don't resend patches if the previous submission came to the
> conclusion that it's unclear how this should help.
>
>
> https://lkml.kernel.org/r/cajsp0qw396ry_g8ls1mncdzcov5gamury+xv+s8zmcdq03o...@mail.gmail.com
>
>
> I *still* don't understand the interaction between the lock and the
> assertion and so far nobody was able to clarify.
>
> --
> Thanks,
>
> David / dhildenb
>
hello
This message is sent way before the discussion
>
