Hi, this is your Linux kernel regression tracker speaking. On 15.12.21 18:20, Greg Kroah-Hartman wrote: > From: Alaa Hleihel <alaa@xxxxxxxxxx> > > [ Upstream commit f0ae4afe3d35e67db042c58a52909e06262b740f ] > > For the case of IB_MR_TYPE_DM the mr does doesn't have a umem, even though > it is a user MR. This causes function mlx5_free_priv_descs() to think that > it is a kernel MR, leading to wrongly accessing mr->descs that will get > wrong values in the union which leads to attempt to release resources that > were not allocated in the first place. TWIMC, that commit made it into 5.15.y, but is known to cause a regression in v5.16-rc: https://lore.kernel.org/lkml/f298db4ec5fdf7a2d1d166ca2f66020fd9397e5c.1640079962.git.leonro@xxxxxxxxxx/ https://lore.kernel.org/all/EEBA2D1C-F29C-4237-901C-587B60CEE113@xxxxxxxxxx/ A fix for mainline was posted, but got stuck afaics: https://lore.kernel.org/lkml/f298db4ec5fdf7a2d1d166ca2f66020fd9397e5c.1640079962.git.leonro@xxxxxxxxxx/ A revert was also discussed, but not performed: https://lore.kernel.org/all/20211222101312.1358616-1-maorg@xxxxxxxxxx/ Ciao, Thorsten > For example: > DMA-API: mlx5_core 0000:08:00.1: device driver tries to free DMA memory it has not allocated [device address=0x0000000000000000] [size=0 bytes] > WARNING: CPU: 8 PID: 1021 at kernel/dma/debug.c:961 check_unmap+0x54f/0x8b0 > RIP: 0010:check_unmap+0x54f/0x8b0 > Call Trace: > debug_dma_unmap_page+0x57/0x60 > mlx5_free_priv_descs+0x57/0x70 [mlx5_ib] > mlx5_ib_dereg_mr+0x1fb/0x3d0 [mlx5_ib] > ib_dereg_mr_user+0x60/0x140 [ib_core] > uverbs_destroy_uobject+0x59/0x210 [ib_uverbs] > uobj_destroy+0x3f/0x80 [ib_uverbs] > ib_uverbs_cmd_verbs+0x435/0xd10 [ib_uverbs] > ? uverbs_finalize_object+0x50/0x50 [ib_uverbs] > ? lock_acquire+0xc4/0x2e0 > ? lock_acquired+0x12/0x380 > ? lock_acquire+0xc4/0x2e0 > ? lock_acquire+0xc4/0x2e0 > ? ib_uverbs_ioctl+0x7c/0x140 [ib_uverbs] > ? lock_release+0x28a/0x400 > ib_uverbs_ioctl+0xc0/0x140 [ib_uverbs] > ? ib_uverbs_ioctl+0x7c/0x140 [ib_uverbs] > __x64_sys_ioctl+0x7f/0xb0 > do_syscall_64+0x38/0x90 > > Fix it by reorganizing the dereg flow and mlx5_ib_mr structure: > - Move the ib_umem field into the user MRs structure in the union as it's > applicable only there. > - Function mlx5_ib_dereg_mr() will now call mlx5_free_priv_descs() only > in case there isn't udata, which indicates that this isn't a user MR. > > Fixes: f18ec4223117 ("RDMA/mlx5: Use a union inside mlx5_ib_mr") > Link: https://lore.kernel.org/r/66bb1dd253c1fd7ceaa9fc411061eefa457b86fb.1637581144.git.leonro@xxxxxxxxxx > Signed-off-by: Alaa Hleihel <alaa@xxxxxxxxxx> > Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxx> > Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > --- > drivers/infiniband/hw/mlx5/mlx5_ib.h | 6 +++--- > drivers/infiniband/hw/mlx5/mr.c | 26 ++++++++++++-------------- > 2 files changed, 15 insertions(+), 17 deletions(-) > > diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h > index bf20a388eabe1..6204ae2caef58 100644 > --- a/drivers/infiniband/hw/mlx5/mlx5_ib.h > +++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h > @@ -641,7 +641,6 @@ struct mlx5_ib_mr { > > /* User MR data */ > struct mlx5_cache_ent *cache_ent; > - struct ib_umem *umem; > > /* This is zero'd when the MR is allocated */ > union { > @@ -653,7 +652,7 @@ struct mlx5_ib_mr { > struct list_head list; > }; > > - /* Used only by kernel MRs (umem == NULL) */ > + /* Used only by kernel MRs */ > struct { > void *descs; > void *descs_alloc; > @@ -675,8 +674,9 @@ struct mlx5_ib_mr { > int data_length; > }; > > - /* Used only by User MRs (umem != NULL) */ > + /* Used only by User MRs */ > struct { > + struct ib_umem *umem; > unsigned int page_shift; > /* Current access_flags */ > int access_flags; > diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c > index 22e2f4d79743d..69b2ce4c292ae 100644 > --- a/drivers/infiniband/hw/mlx5/mr.c > +++ b/drivers/infiniband/hw/mlx5/mr.c > @@ -1911,19 +1911,18 @@ mlx5_alloc_priv_descs(struct ib_device *device, > return ret; > } > > -static void > -mlx5_free_priv_descs(struct mlx5_ib_mr *mr) > +static void mlx5_free_priv_descs(struct mlx5_ib_mr *mr) > { > - if (!mr->umem && mr->descs) { > - struct ib_device *device = mr->ibmr.device; > - int size = mr->max_descs * mr->desc_size; > - struct mlx5_ib_dev *dev = to_mdev(device); > + struct mlx5_ib_dev *dev = to_mdev(mr->ibmr.device); > + int size = mr->max_descs * mr->desc_size; > > - dma_unmap_single(&dev->mdev->pdev->dev, mr->desc_map, size, > - DMA_TO_DEVICE); > - kfree(mr->descs_alloc); > - mr->descs = NULL; > - } > + if (!mr->descs) > + return; > + > + dma_unmap_single(&dev->mdev->pdev->dev, mr->desc_map, size, > + DMA_TO_DEVICE); > + kfree(mr->descs_alloc); > + mr->descs = NULL; > } > > int mlx5_ib_dereg_mr(struct ib_mr *ibmr, struct ib_udata *udata) > @@ -1999,7 +1998,8 @@ int mlx5_ib_dereg_mr(struct ib_mr *ibmr, struct ib_udata *udata) > if (mr->cache_ent) { > mlx5_mr_cache_free(dev, mr); > } else { > - mlx5_free_priv_descs(mr); > + if (!udata) > + mlx5_free_priv_descs(mr); > kfree(mr); > } > return 0; > @@ -2086,7 +2086,6 @@ static struct mlx5_ib_mr *mlx5_ib_alloc_pi_mr(struct ib_pd *pd, > if (err) > goto err_free_in; > > - mr->umem = NULL; > kfree(in); > > return mr; > @@ -2213,7 +2212,6 @@ static struct ib_mr *__mlx5_ib_alloc_mr(struct ib_pd *pd, > } > > mr->ibmr.device = pd->device; > - mr->umem = NULL; > > switch (mr_type) { > case IB_MR_TYPE_MEM_REG:
