Messages in this thread | | | Subject | Re: [PATCH V2] nvme-rdma: fix double free in nvme_rdma_free_queue | From | Max Gurtovoy <> | Date | Wed, 16 May 2018 15:18:47 +0300 |
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Hi Jianchao,
On 5/10/2018 12:42 PM, Jianchao Wang wrote: > BUG: KASAN: double-free or invalid-free in nvme_rdma_free_queue+0xf6/0x110 [nvme_rdma] > Workqueue: nvme-reset-wq nvme_rdma_reset_ctrl_work [nvme_rdma] > Call Trace: > dump_stack+0x91/0xeb > print_address_description+0x6b/0x290 > kasan_report_invalid_free+0x55/0x80 > __kasan_slab_free+0x176/0x190 > kfree+0xeb/0x310 > nvme_rdma_free_queue+0xf6/0x110 [nvme_rdma] > nvme_rdma_configure_admin_queue+0x1a3/0x4d0 [nvme_rdma] > nvme_rdma_reset_ctrl_work+0x4e/0xd0 [nvme_rdma] > process_one_work+0x3ca/0xaa0 > worker_thread+0x4e2/0x6c0 > kthread+0x18d/0x1e0 > ret_from_fork+0x24/0x30 > > The double free is on ctrl->async_event_sqe. > If any case fails before ctrl->async_event_sqe is allocated in > nvme_rdma_configure_admin_queue, nvme_rdma_free_queue will be > invoked. However, at the moment, the ctrl->async_event_sqe has > not been allocated because it has been freed in > nvme_rdma_reset_ctrl_work > -> nvme_rdma_shutdown_ctrl > ->nvme_rdma_destroy_admin_queue > -> nvme_rdma_free_queue > > Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> > --- > > V2: > handle it in nvme_rdma_free_queue and add some comment to explain it.
I don't know exactly what Christoph meant but IMO the best place to allocate it is in nvme_rdma_alloc_queue just before calling
"set_bit(NVME_RDMA_Q_ALLOCATED, &queue->flags);"
then you will never get to double free since we clear the NVME_RDMA_Q_ALLOCATED bit in the beginning of nvme_rdma_free_queue.
> > drivers/nvme/host/rdma.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c > index 966e0dd..fa5cf87 100644 > --- a/drivers/nvme/host/rdma.c > +++ b/drivers/nvme/host/rdma.c > @@ -561,9 +561,18 @@ static void nvme_rdma_free_queue(struct nvme_rdma_queue *queue) > return; > > if (nvme_rdma_queue_idx(queue) == 0) { > - nvme_rdma_free_qe(queue->device->dev, > - &queue->ctrl->async_event_sqe, > - sizeof(struct nvme_command), DMA_TO_DEVICE); > + /* > + * async_event_sqe is not allocated in nvme_rdma_alloc_queue. > + * so there are cases where NVME_RDMA_Q_ALLOCATED is set, but > + * async_event_sqe is not allocated. To avoid double free, set > + * async_event_sqe.data to NULL to indicate it has been freed. > + */ > + if (queue->ctrl->async_event_sqe.data) { > + nvme_rdma_free_qe(queue->device->dev, > + &queue->ctrl->async_event_sqe, > + sizeof(struct nvme_command), DMA_TO_DEVICE); > + queue->ctrl->async_event_sqe.data = NULL; > + } > } > > nvme_rdma_destroy_queue_ib(queue); >
-Max.
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