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