On 29.06.22 10:31, Tong Zhang wrote: > > > On Wed, Jun 29, 2022 at 12:29 AM David Hildenbrand <da...@redhat.com > <mailto: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 > <mailto:f.lond...@samsung.com>> > > Signed-off-by: Tong Zhang <t.zha...@samsung.com > <mailto: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 > > <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
Oh, I'm sorry. I was mislead by the reply from Laurent :) BTW, do we now have an understanding why that patch helps and if it applies to upstream? -- Thanks, David / dhildenb
