[v1] RDMA/core: Avoid hmm_dma_map_alloc() for virtual DMA devices

[PATCH for-next v1] RDMA/core: Avoid hmm_dma_map_alloc() for virtual DMA devices

Posted by Daisuke Matsuda 6 months, 3 weeks ago

Drivers such as rxe, which use virtual DMA, must not call into the DMA
mapping core since they lack physical DMA capabilities. Otherwise, a NULL
pointer dereference is observed as shown below. This patch ensures the RDMA
core handles virtual and physical DMA paths appropriately.

This fixes the following kernel oops:

 BUG: kernel NULL pointer dereference, address: 00000000000002fc
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 1028eb067 P4D 1028eb067 PUD 105da0067 PMD 0
 Oops: Oops: 0000 [#1] SMP NOPTI
 CPU: 3 UID: 1000 PID: 1854 Comm: python3 Tainted: G        W           6.15.0-rc1+ #11 PREEMPT(voluntary)
 Tainted: [W]=WARN
 Hardware name: Trigkey Key N/Key N, BIOS KEYN101 09/02/2024
 RIP: 0010:hmm_dma_map_alloc+0x25/0x100
 Code: 90 90 90 90 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 49 89 d6 49 c1 e6 0c 41 55 41 54 53 49 39 ce 0f 82 c6 00 00 00 49 89 fc <f6> 87 fc 02 00 00 20 0f 84 af 00 00 00 49 89 f5 48 89 d3 49 89 cf
 RSP: 0018:ffffd3d3420eb830 EFLAGS: 00010246
 RAX: 0000000000001000 RBX: ffff8b727c7f7400 RCX: 0000000000001000
 RDX: 0000000000000001 RSI: ffff8b727c7f74b0 RDI: 0000000000000000
 RBP: ffffd3d3420eb858 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
 R13: 00007262a622a000 R14: 0000000000001000 R15: ffff8b727c7f74b0
 FS:  00007262a62a1080(0000) GS:ffff8b762ac3e000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00000000000002fc CR3: 000000010a1f0004 CR4: 0000000000f72ef0
 PKRU: 55555554
 Call Trace:
  <TASK>
  ib_init_umem_odp+0xb6/0x110 [ib_uverbs]
  ib_umem_odp_get+0xf0/0x150 [ib_uverbs]
  rxe_odp_mr_init_user+0x71/0x170 [rdma_rxe]
  rxe_reg_user_mr+0x217/0x2e0 [rdma_rxe]
  ib_uverbs_reg_mr+0x19e/0x2e0 [ib_uverbs]
  ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0xd9/0x150 [ib_uverbs]
  ib_uverbs_cmd_verbs+0xd19/0xee0 [ib_uverbs]
  ? mmap_region+0x63/0xd0
  ? __pfx_ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0x10/0x10 [ib_uverbs]
  ib_uverbs_ioctl+0xba/0x130 [ib_uverbs]
  __x64_sys_ioctl+0xa4/0xe0
  x64_sys_call+0x1178/0x2660
  do_syscall_64+0x7e/0x170
  ? syscall_exit_to_user_mode+0x4e/0x250
  ? do_syscall_64+0x8a/0x170
  ? do_syscall_64+0x8a/0x170
  ? syscall_exit_to_user_mode+0x4e/0x250
  ? do_syscall_64+0x8a/0x170
  ? syscall_exit_to_user_mode+0x4e/0x250
  ? do_syscall_64+0x8a/0x170
  ? do_user_addr_fault+0x1d2/0x8d0
  ? irqentry_exit_to_user_mode+0x43/0x250
  ? irqentry_exit+0x43/0x50
  ? exc_page_fault+0x93/0x1d0
  entry_SYSCALL_64_after_hwframe+0x76/0x7e
 RIP: 0033:0x7262a6124ded
 Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
 RSP: 002b:00007fffd08c3960 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
 RAX: ffffffffffffffda RBX: 00007fffd08c39f0 RCX: 00007262a6124ded
 RDX: 00007fffd08c3a10 RSI: 00000000c0181b01 RDI: 0000000000000007
 RBP: 00007fffd08c39b0 R08: 0000000014107820 R09: 00007fffd08c3b44
 R10: 000000000000000c R11: 0000000000000246 R12: 00007fffd08c3b44
 R13: 000000000000000c R14: 00007fffd08c3b58 R15: 0000000014107960
  </TASK>

Fixes: 1efe8c0670d6 ("RDMA/core: Convert UMEM ODP DMA mapping to caching IOVA and page linkage")
Closes: https://lore.kernel.org/all/3e8f343f-7d66-4f7a-9f08-3910623e322f@gmail.com/
Signed-off-by: Daisuke Matsuda <dskmtsd@gmail.com>
---
 drivers/infiniband/core/device.c   | 24 ++++++++++++++++++++++++
 drivers/infiniband/core/umem_odp.c |  6 +++---
 include/rdma/ib_verbs.h            | 12 ++++++++++++
 3 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index b4e3e4beb7f4..8be4797c66ec 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -2864,6 +2864,30 @@ int ib_dma_virt_map_sg(struct ib_device *dev, struct scatterlist *sg, int nents)
 	return nents;
 }
 EXPORT_SYMBOL(ib_dma_virt_map_sg);
+int ib_dma_virt_map_alloc(struct device *dev, struct hmm_dma_map *map,
+			  size_t nr_entries, size_t dma_entry_size)
+{
+	if (!(nr_entries * PAGE_SIZE / dma_entry_size))
+		return -EINVAL;
+
+	map->dma_entry_size = dma_entry_size;
+	map->pfn_list = kvcalloc(nr_entries, sizeof(*map->pfn_list),
+				 GFP_KERNEL | __GFP_NOWARN);
+	if (!map->pfn_list)
+		return -ENOMEM;
+
+	map->dma_list = kvcalloc(nr_entries, sizeof(*map->dma_list),
+				 GFP_KERNEL | __GFP_NOWARN);
+	if (!map->dma_list)
+		goto err_dma;
+
+	return 0;
+
+err_dma:
+	kvfree(map->pfn_list);
+	return -ENOMEM;
+}
+EXPORT_SYMBOL(ib_dma_virt_map_alloc);
 #endif /* CONFIG_INFINIBAND_VIRT_DMA */
 
 static const struct rdma_nl_cbs ibnl_ls_cb_table[RDMA_NL_LS_NUM_OPS] = {
diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c
index 51d518989914..aa03f3fc84d0 100644
--- a/drivers/infiniband/core/umem_odp.c
+++ b/drivers/infiniband/core/umem_odp.c
@@ -75,9 +75,9 @@ static int ib_init_umem_odp(struct ib_umem_odp *umem_odp,
 	if (unlikely(end < page_size))
 		return -EOVERFLOW;
 
-	ret = hmm_dma_map_alloc(dev->dma_device, &umem_odp->map,
-				(end - start) >> PAGE_SHIFT,
-				1 << umem_odp->page_shift);
+	ret = ib_dma_map_alloc(dev, &umem_odp->map,
+			       (end - start) >> PAGE_SHIFT,
+			       1 << umem_odp->page_shift);
 	if (ret)
 		return ret;
 
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index b06a0ed81bdd..10813f348b99 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -36,6 +36,7 @@
 #include <linux/irqflags.h>
 #include <linux/preempt.h>
 #include <linux/dim.h>
+#include <linux/hmm-dma.h>
 #include <uapi/rdma/ib_user_verbs.h>
 #include <rdma/rdma_counter.h>
 #include <rdma/restrack.h>
@@ -4221,6 +4222,17 @@ static inline void ib_dma_unmap_sg_attrs(struct ib_device *dev,
 				   dma_attrs);
 }
 
+int ib_dma_virt_map_alloc(struct device *dev, struct hmm_dma_map *map,
+			  size_t nr_entries, size_t dma_entry_size);
+static inline int ib_dma_map_alloc(struct ib_device *dev, struct hmm_dma_map *map,
+				   size_t nr_entries, size_t dma_entry_size)
+{
+	if (ib_uses_virt_dma(dev))
+		return ib_dma_virt_map_alloc(dev->dma_device, map, nr_entries,
+					     dma_entry_size);
+	return hmm_dma_map_alloc(dev->dma_device, map, nr_entries, dma_entry_size);
+}
+
 /**
  * ib_dma_map_sgtable_attrs - Map a scatter/gather table to DMA addresses
  * @dev: The device for which the DMA addresses are to be created
-- 
2.43.0

Re: [PATCH for-next v1] RDMA/core: Avoid hmm_dma_map_alloc() for virtual DMA devices

Posted by Leon Romanovsky 6 months, 3 weeks ago

On Fri, May 23, 2025 at 06:47:01PM +0000, Daisuke Matsuda wrote:
> Drivers such as rxe, which use virtual DMA, must not call into the DMA
> mapping core since they lack physical DMA capabilities. Otherwise, a NULL
> pointer dereference is observed as shown below. This patch ensures the RDMA
> core handles virtual and physical DMA paths appropriately.
> 
> This fixes the following kernel oops:
> 
>  BUG: kernel NULL pointer dereference, address: 00000000000002fc
>  #PF: supervisor read access in kernel mode
>  #PF: error_code(0x0000) - not-present page
>  PGD 1028eb067 P4D 1028eb067 PUD 105da0067 PMD 0
>  Oops: Oops: 0000 [#1] SMP NOPTI
>  CPU: 3 UID: 1000 PID: 1854 Comm: python3 Tainted: G        W           6.15.0-rc1+ #11 PREEMPT(voluntary)
>  Tainted: [W]=WARN
>  Hardware name: Trigkey Key N/Key N, BIOS KEYN101 09/02/2024
>  RIP: 0010:hmm_dma_map_alloc+0x25/0x100
>  Code: 90 90 90 90 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 49 89 d6 49 c1 e6 0c 41 55 41 54 53 49 39 ce 0f 82 c6 00 00 00 49 89 fc <f6> 87 fc 02 00 00 20 0f 84 af 00 00 00 49 89 f5 48 89 d3 49 89 cf
>  RSP: 0018:ffffd3d3420eb830 EFLAGS: 00010246
>  RAX: 0000000000001000 RBX: ffff8b727c7f7400 RCX: 0000000000001000
>  RDX: 0000000000000001 RSI: ffff8b727c7f74b0 RDI: 0000000000000000
>  RBP: ffffd3d3420eb858 R08: 0000000000000000 R09: 0000000000000000
>  R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
>  R13: 00007262a622a000 R14: 0000000000001000 R15: ffff8b727c7f74b0
>  FS:  00007262a62a1080(0000) GS:ffff8b762ac3e000(0000) knlGS:0000000000000000
>  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>  CR2: 00000000000002fc CR3: 000000010a1f0004 CR4: 0000000000f72ef0
>  PKRU: 55555554
>  Call Trace:
>   <TASK>
>   ib_init_umem_odp+0xb6/0x110 [ib_uverbs]
>   ib_umem_odp_get+0xf0/0x150 [ib_uverbs]
>   rxe_odp_mr_init_user+0x71/0x170 [rdma_rxe]
>   rxe_reg_user_mr+0x217/0x2e0 [rdma_rxe]
>   ib_uverbs_reg_mr+0x19e/0x2e0 [ib_uverbs]
>   ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0xd9/0x150 [ib_uverbs]
>   ib_uverbs_cmd_verbs+0xd19/0xee0 [ib_uverbs]
>   ? mmap_region+0x63/0xd0
>   ? __pfx_ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0x10/0x10 [ib_uverbs]
>   ib_uverbs_ioctl+0xba/0x130 [ib_uverbs]
>   __x64_sys_ioctl+0xa4/0xe0
>   x64_sys_call+0x1178/0x2660
>   do_syscall_64+0x7e/0x170
>   ? syscall_exit_to_user_mode+0x4e/0x250
>   ? do_syscall_64+0x8a/0x170
>   ? do_syscall_64+0x8a/0x170
>   ? syscall_exit_to_user_mode+0x4e/0x250
>   ? do_syscall_64+0x8a/0x170
>   ? syscall_exit_to_user_mode+0x4e/0x250
>   ? do_syscall_64+0x8a/0x170
>   ? do_user_addr_fault+0x1d2/0x8d0
>   ? irqentry_exit_to_user_mode+0x43/0x250
>   ? irqentry_exit+0x43/0x50
>   ? exc_page_fault+0x93/0x1d0
>   entry_SYSCALL_64_after_hwframe+0x76/0x7e
>  RIP: 0033:0x7262a6124ded
>  Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
>  RSP: 002b:00007fffd08c3960 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
>  RAX: ffffffffffffffda RBX: 00007fffd08c39f0 RCX: 00007262a6124ded
>  RDX: 00007fffd08c3a10 RSI: 00000000c0181b01 RDI: 0000000000000007
>  RBP: 00007fffd08c39b0 R08: 0000000014107820 R09: 00007fffd08c3b44
>  R10: 000000000000000c R11: 0000000000000246 R12: 00007fffd08c3b44
>  R13: 000000000000000c R14: 00007fffd08c3b58 R15: 0000000014107960
>   </TASK>
> 
> Fixes: 1efe8c0670d6 ("RDMA/core: Convert UMEM ODP DMA mapping to caching IOVA and page linkage")
> Closes: https://lore.kernel.org/all/3e8f343f-7d66-4f7a-9f08-3910623e322f@gmail.com/
> Signed-off-by: Daisuke Matsuda <dskmtsd@gmail.com>
> ---
>  drivers/infiniband/core/device.c   | 24 ++++++++++++++++++++++++
>  drivers/infiniband/core/umem_odp.c |  6 +++---
>  include/rdma/ib_verbs.h            | 12 ++++++++++++
>  3 files changed, 39 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
> index b4e3e4beb7f4..8be4797c66ec 100644
> --- a/drivers/infiniband/core/device.c
> +++ b/drivers/infiniband/core/device.c
> @@ -2864,6 +2864,30 @@ int ib_dma_virt_map_sg(struct ib_device *dev, struct scatterlist *sg, int nents)
>  	return nents;
>  }
>  EXPORT_SYMBOL(ib_dma_virt_map_sg);
> +int ib_dma_virt_map_alloc(struct device *dev, struct hmm_dma_map *map,
> +			  size_t nr_entries, size_t dma_entry_size)
> +{
> +	if (!(nr_entries * PAGE_SIZE / dma_entry_size))
> +		return -EINVAL;
> +
> +	map->dma_entry_size = dma_entry_size;
> +	map->pfn_list = kvcalloc(nr_entries, sizeof(*map->pfn_list),
> +				 GFP_KERNEL | __GFP_NOWARN);
> +	if (!map->pfn_list)
> +		return -ENOMEM;

pfn_list is enough, virtual devices doesn't go through path which needs
dma_list. They use simple CPU address to DMA address translation.

> +
> +	map->dma_list = kvcalloc(nr_entries, sizeof(*map->dma_list),
> +				 GFP_KERNEL | __GFP_NOWARN);
> +	if (!map->dma_list)
> +		goto err_dma;
> +
> +	return 0;
> +
> +err_dma:
> +	kvfree(map->pfn_list);
> +	return -ENOMEM;
> +}
> +EXPORT_SYMBOL(ib_dma_virt_map_alloc);
>  #endif /* CONFIG_INFINIBAND_VIRT_DMA */
>  
>  static const struct rdma_nl_cbs ibnl_ls_cb_table[RDMA_NL_LS_NUM_OPS] = {
> diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c
> index 51d518989914..aa03f3fc84d0 100644
> --- a/drivers/infiniband/core/umem_odp.c
> +++ b/drivers/infiniband/core/umem_odp.c
> @@ -75,9 +75,9 @@ static int ib_init_umem_odp(struct ib_umem_odp *umem_odp,
>  	if (unlikely(end < page_size))
>  		return -EOVERFLOW;
>  
> -	ret = hmm_dma_map_alloc(dev->dma_device, &umem_odp->map,
> -				(end - start) >> PAGE_SHIFT,
> -				1 << umem_odp->page_shift);
> +	ret = ib_dma_map_alloc(dev, &umem_odp->map,
> +			       (end - start) >> PAGE_SHIFT,
> +			       1 << umem_odp->page_shift);

There is no need in extra function, implement if(ib_uses_virt_dma...) here.

Thanks

Re: [PATCH for-next v1] RDMA/core: Avoid hmm_dma_map_alloc() for virtual DMA devices

Posted by Zhu Yanjun 6 months, 3 weeks ago

在 2025/5/23 20:47, Daisuke Matsuda 写道:
> Drivers such as rxe, which use virtual DMA, must not call into the DMA
> mapping core since they lack physical DMA capabilities. Otherwise, a NULL
> pointer dereference is observed as shown below. This patch ensures the RDMA
> core handles virtual and physical DMA paths appropriately.
> 
> This fixes the following kernel oops:
> 
>   BUG: kernel NULL pointer dereference, address: 00000000000002fc
>   #PF: supervisor read access in kernel mode
>   #PF: error_code(0x0000) - not-present page
>   PGD 1028eb067 P4D 1028eb067 PUD 105da0067 PMD 0
>   Oops: Oops: 0000 [#1] SMP NOPTI
>   CPU: 3 UID: 1000 PID: 1854 Comm: python3 Tainted: G        W           6.15.0-rc1+ #11 PREEMPT(voluntary)
>   Tainted: [W]=WARN
>   Hardware name: Trigkey Key N/Key N, BIOS KEYN101 09/02/2024
>   RIP: 0010:hmm_dma_map_alloc+0x25/0x100
>   Code: 90 90 90 90 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 49 89 d6 49 c1 e6 0c 41 55 41 54 53 49 39 ce 0f 82 c6 00 00 00 49 89 fc <f6> 87 fc 02 00 00 20 0f 84 af 00 00 00 49 89 f5 48 89 d3 49 89 cf
>   RSP: 0018:ffffd3d3420eb830 EFLAGS: 00010246
>   RAX: 0000000000001000 RBX: ffff8b727c7f7400 RCX: 0000000000001000
>   RDX: 0000000000000001 RSI: ffff8b727c7f74b0 RDI: 0000000000000000
>   RBP: ffffd3d3420eb858 R08: 0000000000000000 R09: 0000000000000000
>   R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
>   R13: 00007262a622a000 R14: 0000000000001000 R15: ffff8b727c7f74b0
>   FS:  00007262a62a1080(0000) GS:ffff8b762ac3e000(0000) knlGS:0000000000000000
>   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>   CR2: 00000000000002fc CR3: 000000010a1f0004 CR4: 0000000000f72ef0
>   PKRU: 55555554
>   Call Trace:
>    <TASK>
>    ib_init_umem_odp+0xb6/0x110 [ib_uverbs]
>    ib_umem_odp_get+0xf0/0x150 [ib_uverbs]
>    rxe_odp_mr_init_user+0x71/0x170 [rdma_rxe]
>    rxe_reg_user_mr+0x217/0x2e0 [rdma_rxe]
>    ib_uverbs_reg_mr+0x19e/0x2e0 [ib_uverbs]
>    ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0xd9/0x150 [ib_uverbs]
>    ib_uverbs_cmd_verbs+0xd19/0xee0 [ib_uverbs]
>    ? mmap_region+0x63/0xd0
>    ? __pfx_ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0x10/0x10 [ib_uverbs]
>    ib_uverbs_ioctl+0xba/0x130 [ib_uverbs]
>    __x64_sys_ioctl+0xa4/0xe0
>    x64_sys_call+0x1178/0x2660
>    do_syscall_64+0x7e/0x170
>    ? syscall_exit_to_user_mode+0x4e/0x250
>    ? do_syscall_64+0x8a/0x170
>    ? do_syscall_64+0x8a/0x170
>    ? syscall_exit_to_user_mode+0x4e/0x250
>    ? do_syscall_64+0x8a/0x170
>    ? syscall_exit_to_user_mode+0x4e/0x250
>    ? do_syscall_64+0x8a/0x170
>    ? do_user_addr_fault+0x1d2/0x8d0
>    ? irqentry_exit_to_user_mode+0x43/0x250
>    ? irqentry_exit+0x43/0x50
>    ? exc_page_fault+0x93/0x1d0
>    entry_SYSCALL_64_after_hwframe+0x76/0x7e
>   RIP: 0033:0x7262a6124ded
>   Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
>   RSP: 002b:00007fffd08c3960 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
>   RAX: ffffffffffffffda RBX: 00007fffd08c39f0 RCX: 00007262a6124ded
>   RDX: 00007fffd08c3a10 RSI: 00000000c0181b01 RDI: 0000000000000007
>   RBP: 00007fffd08c39b0 R08: 0000000014107820 R09: 00007fffd08c3b44
>   R10: 000000000000000c R11: 0000000000000246 R12: 00007fffd08c3b44
>   R13: 000000000000000c R14: 00007fffd08c3b58 R15: 0000000014107960
>    </TASK>
> 
> Fixes: 1efe8c0670d6 ("RDMA/core: Convert UMEM ODP DMA mapping to caching IOVA and page linkage")
> Closes: https://lore.kernel.org/all/3e8f343f-7d66-4f7a-9f08-3910623e322f@gmail.com/
> Signed-off-by: Daisuke Matsuda <dskmtsd@gmail.com>
> ---
>   drivers/infiniband/core/device.c   | 24 ++++++++++++++++++++++++
>   drivers/infiniband/core/umem_odp.c |  6 +++---
>   include/rdma/ib_verbs.h            | 12 ++++++++++++
>   3 files changed, 39 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
> index b4e3e4beb7f4..8be4797c66ec 100644
> --- a/drivers/infiniband/core/device.c
> +++ b/drivers/infiniband/core/device.c
> @@ -2864,6 +2864,30 @@ int ib_dma_virt_map_sg(struct ib_device *dev, struct scatterlist *sg, int nents)
>   	return nents;
>   }
>   EXPORT_SYMBOL(ib_dma_virt_map_sg);
> +int ib_dma_virt_map_alloc(struct device *dev, struct hmm_dma_map *map,
> +			  size_t nr_entries, size_t dma_entry_size)
> +{
> +	if (!(nr_entries * PAGE_SIZE / dma_entry_size))
> +		return -EINVAL;
> +
> +	map->dma_entry_size = dma_entry_size;
> +	map->pfn_list = kvcalloc(nr_entries, sizeof(*map->pfn_list),
> +				 GFP_KERNEL | __GFP_NOWARN);
> +	if (!map->pfn_list)
> +		return -ENOMEM;
> +
> +	map->dma_list = kvcalloc(nr_entries, sizeof(*map->dma_list),
> +				 GFP_KERNEL | __GFP_NOWARN);
> +	if (!map->dma_list)
> +		goto err_dma;
> +
> +	return 0;
> +
> +err_dma:
> +	kvfree(map->pfn_list);
> +	return -ENOMEM;
> +}
> +EXPORT_SYMBOL(ib_dma_virt_map_alloc);
>   #endif /* CONFIG_INFINIBAND_VIRT_DMA */
>   
>   static const struct rdma_nl_cbs ibnl_ls_cb_table[RDMA_NL_LS_NUM_OPS] = {
> diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c
> index 51d518989914..aa03f3fc84d0 100644
> --- a/drivers/infiniband/core/umem_odp.c
> +++ b/drivers/infiniband/core/umem_odp.c
> @@ -75,9 +75,9 @@ static int ib_init_umem_odp(struct ib_umem_odp *umem_odp,
>   	if (unlikely(end < page_size))
>   		return -EOVERFLOW;
>   
> -	ret = hmm_dma_map_alloc(dev->dma_device, &umem_odp->map,
> -				(end - start) >> PAGE_SHIFT,
> -				1 << umem_odp->page_shift);
> +	ret = ib_dma_map_alloc(dev, &umem_odp->map,
> +			       (end - start) >> PAGE_SHIFT,
> +			       1 << umem_odp->page_shift);
>   	if (ret)
>   		return ret;
>   
> diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
> index b06a0ed81bdd..10813f348b99 100644
> --- a/include/rdma/ib_verbs.h
> +++ b/include/rdma/ib_verbs.h
> @@ -36,6 +36,7 @@
>   #include <linux/irqflags.h>
>   #include <linux/preempt.h>
>   #include <linux/dim.h>
> +#include <linux/hmm-dma.h>
>   #include <uapi/rdma/ib_user_verbs.h>
>   #include <rdma/rdma_counter.h>
>   #include <rdma/restrack.h>
> @@ -4221,6 +4222,17 @@ static inline void ib_dma_unmap_sg_attrs(struct ib_device *dev,
>   				   dma_attrs);
>   }
>   
> +int ib_dma_virt_map_alloc(struct device *dev, struct hmm_dma_map *map,
> +			  size_t nr_entries, size_t dma_entry_size);
> +static inline int ib_dma_map_alloc(struct ib_device *dev, struct hmm_dma_map *map,
> +				   size_t nr_entries, size_t dma_entry_size)
> +{
> +	if (ib_uses_virt_dma(dev))
> +		return ib_dma_virt_map_alloc(dev->dma_device, map, nr_entries,
> +					     dma_entry_size);

Other emulated RDMA devices driver also call ib_dma_virt_map_alloc?
Only rxe will call ib_dma_virt_map_alloc?

Zhu Yanjun

> +	return hmm_dma_map_alloc(dev->dma_device, map, nr_entries, dma_entry_size);
> +}
> +
>   /**
>    * ib_dma_map_sgtable_attrs - Map a scatter/gather table to DMA addresses
>    * @dev: The device for which the DMA addresses are to be created

Re: [PATCH for-next v1] RDMA/core: Avoid hmm_dma_map_alloc() for virtual DMA devices

Posted by Zhu Yanjun 6 months, 3 weeks ago


在 2025/5/24 9:31, Zhu Yanjun 写道:
> 在 2025/5/23 20:47, Daisuke Matsuda 写道:
>> Drivers such as rxe, which use virtual DMA, must not call into the DMA
>> mapping core since they lack physical DMA capabilities. Otherwise, a NULL
>> pointer dereference is observed as shown below. This patch ensures the 
>> RDMA
>> core handles virtual and physical DMA paths appropriately.
>>
>> This fixes the following kernel oops:
>>
>>   BUG: kernel NULL pointer dereference, address: 00000000000002fc
>>   #PF: supervisor read access in kernel mode
>>   #PF: error_code(0x0000) - not-present page
>>   PGD 1028eb067 P4D 1028eb067 PUD 105da0067 PMD 0
>>   Oops: Oops: 0000 [#1] SMP NOPTI
>>   CPU: 3 UID: 1000 PID: 1854 Comm: python3 Tainted: G        
>> W           6.15.0-rc1+ #11 PREEMPT(voluntary)
>>   Tainted: [W]=WARN
>>   Hardware name: Trigkey Key N/Key N, BIOS KEYN101 09/02/2024
>>   RIP: 0010:hmm_dma_map_alloc+0x25/0x100
>>   Code: 90 90 90 90 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 49 89 d6 
>> 49 c1 e6 0c 41 55 41 54 53 49 39 ce 0f 82 c6 00 00 00 49 89 fc <f6> 87 
>> fc 02 00 00 20 0f 84 af 00 00 00 49 89 f5 48 89 d3 49 89 cf
>>   RSP: 0018:ffffd3d3420eb830 EFLAGS: 00010246
>>   RAX: 0000000000001000 RBX: ffff8b727c7f7400 RCX: 0000000000001000
>>   RDX: 0000000000000001 RSI: ffff8b727c7f74b0 RDI: 0000000000000000
>>   RBP: ffffd3d3420eb858 R08: 0000000000000000 R09: 0000000000000000
>>   R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
>>   R13: 00007262a622a000 R14: 0000000000001000 R15: ffff8b727c7f74b0
>>   FS:  00007262a62a1080(0000) GS:ffff8b762ac3e000(0000) 
>> knlGS:0000000000000000
>>   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>   CR2: 00000000000002fc CR3: 000000010a1f0004 CR4: 0000000000f72ef0
>>   PKRU: 55555554
>>   Call Trace:
>>    <TASK>
>>    ib_init_umem_odp+0xb6/0x110 [ib_uverbs]
>>    ib_umem_odp_get+0xf0/0x150 [ib_uverbs]
>>    rxe_odp_mr_init_user+0x71/0x170 [rdma_rxe]
>>    rxe_reg_user_mr+0x217/0x2e0 [rdma_rxe]
>>    ib_uverbs_reg_mr+0x19e/0x2e0 [ib_uverbs]
>>    ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0xd9/0x150 [ib_uverbs]
>>    ib_uverbs_cmd_verbs+0xd19/0xee0 [ib_uverbs]
>>    ? mmap_region+0x63/0xd0
>>    ? __pfx_ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0x10/0x10 
>> [ib_uverbs]
>>    ib_uverbs_ioctl+0xba/0x130 [ib_uverbs]
>>    __x64_sys_ioctl+0xa4/0xe0
>>    x64_sys_call+0x1178/0x2660
>>    do_syscall_64+0x7e/0x170
>>    ? syscall_exit_to_user_mode+0x4e/0x250
>>    ? do_syscall_64+0x8a/0x170
>>    ? do_syscall_64+0x8a/0x170
>>    ? syscall_exit_to_user_mode+0x4e/0x250
>>    ? do_syscall_64+0x8a/0x170
>>    ? syscall_exit_to_user_mode+0x4e/0x250
>>    ? do_syscall_64+0x8a/0x170
>>    ? do_user_addr_fault+0x1d2/0x8d0
>>    ? irqentry_exit_to_user_mode+0x43/0x250
>>    ? irqentry_exit+0x43/0x50
>>    ? exc_page_fault+0x93/0x1d0
>>    entry_SYSCALL_64_after_hwframe+0x76/0x7e
>>   RIP: 0033:0x7262a6124ded
>>   Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 
>> 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 
>> 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
>>   RSP: 002b:00007fffd08c3960 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
>>   RAX: ffffffffffffffda RBX: 00007fffd08c39f0 RCX: 00007262a6124ded
>>   RDX: 00007fffd08c3a10 RSI: 00000000c0181b01 RDI: 0000000000000007
>>   RBP: 00007fffd08c39b0 R08: 0000000014107820 R09: 00007fffd08c3b44
>>   R10: 000000000000000c R11: 0000000000000246 R12: 00007fffd08c3b44
>>   R13: 000000000000000c R14: 00007fffd08c3b58 R15: 0000000014107960
>>    </TASK>
>>
>> Fixes: 1efe8c0670d6 ("RDMA/core: Convert UMEM ODP DMA mapping to 
>> caching IOVA and page linkage")
>> Closes: https://lore.kernel.org/ 
>> all/3e8f343f-7d66-4f7a-9f08-3910623e322f@gmail.com/
>> Signed-off-by: Daisuke Matsuda <dskmtsd@gmail.com>
>> ---
>>   drivers/infiniband/core/device.c   | 24 ++++++++++++++++++++++++
>>   drivers/infiniband/core/umem_odp.c |  6 +++---
>>   include/rdma/ib_verbs.h            | 12 ++++++++++++
>>   3 files changed, 39 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/ 
>> core/device.c
>> index b4e3e4beb7f4..8be4797c66ec 100644
>> --- a/drivers/infiniband/core/device.c
>> +++ b/drivers/infiniband/core/device.c
>> @@ -2864,6 +2864,30 @@ int ib_dma_virt_map_sg(struct ib_device *dev, 
>> struct scatterlist *sg, int nents)
>>       return nents;
>>   }
>>   EXPORT_SYMBOL(ib_dma_virt_map_sg);
>> +int ib_dma_virt_map_alloc(struct device *dev, struct hmm_dma_map *map,
>> +              size_t nr_entries, size_t dma_entry_size)
>> +{
>> +    if (!(nr_entries * PAGE_SIZE / dma_entry_size))
>> +        return -EINVAL;
>> +
>> +    map->dma_entry_size = dma_entry_size;
>> +    map->pfn_list = kvcalloc(nr_entries, sizeof(*map->pfn_list),
>> +                 GFP_KERNEL | __GFP_NOWARN);
>> +    if (!map->pfn_list)
>> +        return -ENOMEM;
>> +
>> +    map->dma_list = kvcalloc(nr_entries, sizeof(*map->dma_list),
>> +                 GFP_KERNEL | __GFP_NOWARN);
>> +    if (!map->dma_list)
>> +        goto err_dma;
>> +
>> +    return 0;
>> +
>> +err_dma:
>> +    kvfree(map->pfn_list);
>> +    return -ENOMEM;
>> +}
>> +EXPORT_SYMBOL(ib_dma_virt_map_alloc);
>>   #endif /* CONFIG_INFINIBAND_VIRT_DMA */
>>   static const struct rdma_nl_cbs ibnl_ls_cb_table[RDMA_NL_LS_NUM_OPS] 
>> = {
>> diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/ 
>> core/umem_odp.c
>> index 51d518989914..aa03f3fc84d0 100644
>> --- a/drivers/infiniband/core/umem_odp.c
>> +++ b/drivers/infiniband/core/umem_odp.c
>> @@ -75,9 +75,9 @@ static int ib_init_umem_odp(struct ib_umem_odp 
>> *umem_odp,
>>       if (unlikely(end < page_size))
>>           return -EOVERFLOW;
>> -    ret = hmm_dma_map_alloc(dev->dma_device, &umem_odp->map,
>> -                (end - start) >> PAGE_SHIFT,
>> -                1 << umem_odp->page_shift);
>> +    ret = ib_dma_map_alloc(dev, &umem_odp->map,
>> +                   (end - start) >> PAGE_SHIFT,
>> +                   1 << umem_odp->page_shift);
>>       if (ret)
>>           return ret;
>> diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
>> index b06a0ed81bdd..10813f348b99 100644
>> --- a/include/rdma/ib_verbs.h
>> +++ b/include/rdma/ib_verbs.h
>> @@ -36,6 +36,7 @@
>>   #include <linux/irqflags.h>
>>   #include <linux/preempt.h>
>>   #include <linux/dim.h>
>> +#include <linux/hmm-dma.h>
>>   #include <uapi/rdma/ib_user_verbs.h>
>>   #include <rdma/rdma_counter.h>
>>   #include <rdma/restrack.h>
>> @@ -4221,6 +4222,17 @@ static inline void ib_dma_unmap_sg_attrs(struct 
>> ib_device *dev,
>>                      dma_attrs);
>>   }
>> +int ib_dma_virt_map_alloc(struct device *dev, struct hmm_dma_map *map,
>> +              size_t nr_entries, size_t dma_entry_size);
>> +static inline int ib_dma_map_alloc(struct ib_device *dev, struct 
>> hmm_dma_map *map,
>> +                   size_t nr_entries, size_t dma_entry_size)
>> +{
>> +    if (ib_uses_virt_dma(dev))
>> +        return ib_dma_virt_map_alloc(dev->dma_device, map, nr_entries,
>> +                         dma_entry_size);
> 
> Other emulated RDMA devices driver also call ib_dma_virt_map_alloc?
> Only rxe will call ib_dma_virt_map_alloc?

As I know, other emulated RDMA driver also implemented ODP, and with the 
current hmm_dma_map_alloc, it can work well.
So in the above "if (ib_uses_virt_dma(dev))", changed to if (rxe_dev), 
then go to call ib_dma_virt_map_alloc.

Yanjun.Zhu

> 
> Zhu Yanjun
> 
>> +    return hmm_dma_map_alloc(dev->dma_device, map, nr_entries, 
>> dma_entry_size);
>> +}
>> +
>>   /**
>>    * ib_dma_map_sgtable_attrs - Map a scatter/gather table to DMA 
>> addresses
>>    * @dev: The device for which the DMA addresses are to be created
> 

-- 
Best Regards,
Yanjun.Zhu

Re: [PATCH for-next v1] RDMA/core: Avoid hmm_dma_map_alloc() for virtual DMA devices

Posted by Daisuke Matsuda 6 months, 3 weeks ago

On 2025/05/24 16:52, Zhu Yanjun wrote:
> 在 2025/5/24 9:31, Zhu Yanjun 写道:
>> 在 2025/5/23 20:47, Daisuke Matsuda 写道:
>>> Drivers such as rxe, which use virtual DMA, must not call into the DMA
>>> mapping core since they lack physical DMA capabilities. Otherwise, a NULL
>>> pointer dereference is observed as shown below. This patch ensures the RDMA
>>> core handles virtual and physical DMA paths appropriately.
>>>
>>> This fixes the following kernel oops:
>>>
>>>   BUG: kernel NULL pointer dereference, address: 00000000000002fc
>>>   #PF: supervisor read access in kernel mode
>>>   #PF: error_code(0x0000) - not-present page
>>>   PGD 1028eb067 P4D 1028eb067 PUD 105da0067 PMD 0
>>>   Oops: Oops: 0000 [#1] SMP NOPTI
>>>   CPU: 3 UID: 1000 PID: 1854 Comm: python3 Tainted: G W           6.15.0-rc1+ #11 PREEMPT(voluntary)
>>>   Tainted: [W]=WARN
>>>   Hardware name: Trigkey Key N/Key N, BIOS KEYN101 09/02/2024
>>>   RIP: 0010:hmm_dma_map_alloc+0x25/0x100
>>>   Code: 90 90 90 90 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 49 89 d6 49 c1 e6 0c 41 55 41 54 53 49 39 ce 0f 82 c6 00 00 00 49 89 fc <f6> 87 fc 02 00 00 20 0f 84 af 00 00 00 49 89 f5 48 89 d3 49 89 cf
>>>   RSP: 0018:ffffd3d3420eb830 EFLAGS: 00010246
>>>   RAX: 0000000000001000 RBX: ffff8b727c7f7400 RCX: 0000000000001000
>>>   RDX: 0000000000000001 RSI: ffff8b727c7f74b0 RDI: 0000000000000000
>>>   RBP: ffffd3d3420eb858 R08: 0000000000000000 R09: 0000000000000000
>>>   R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
>>>   R13: 00007262a622a000 R14: 0000000000001000 R15: ffff8b727c7f74b0
>>>   FS:  00007262a62a1080(0000) GS:ffff8b762ac3e000(0000) knlGS:0000000000000000
>>>   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>>   CR2: 00000000000002fc CR3: 000000010a1f0004 CR4: 0000000000f72ef0
>>>   PKRU: 55555554
>>>   Call Trace:
>>>    <TASK>
>>>    ib_init_umem_odp+0xb6/0x110 [ib_uverbs]
>>>    ib_umem_odp_get+0xf0/0x150 [ib_uverbs]
>>>    rxe_odp_mr_init_user+0x71/0x170 [rdma_rxe]
>>>    rxe_reg_user_mr+0x217/0x2e0 [rdma_rxe]
>>>    ib_uverbs_reg_mr+0x19e/0x2e0 [ib_uverbs]
>>>    ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0xd9/0x150 [ib_uverbs]
>>>    ib_uverbs_cmd_verbs+0xd19/0xee0 [ib_uverbs]
>>>    ? mmap_region+0x63/0xd0
>>>    ? __pfx_ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0x10/0x10 [ib_uverbs]
>>>    ib_uverbs_ioctl+0xba/0x130 [ib_uverbs]
>>>    __x64_sys_ioctl+0xa4/0xe0
>>>    x64_sys_call+0x1178/0x2660
>>>    do_syscall_64+0x7e/0x170
>>>    ? syscall_exit_to_user_mode+0x4e/0x250
>>>    ? do_syscall_64+0x8a/0x170
>>>    ? do_syscall_64+0x8a/0x170
>>>    ? syscall_exit_to_user_mode+0x4e/0x250
>>>    ? do_syscall_64+0x8a/0x170
>>>    ? syscall_exit_to_user_mode+0x4e/0x250
>>>    ? do_syscall_64+0x8a/0x170
>>>    ? do_user_addr_fault+0x1d2/0x8d0
>>>    ? irqentry_exit_to_user_mode+0x43/0x250
>>>    ? irqentry_exit+0x43/0x50
>>>    ? exc_page_fault+0x93/0x1d0
>>>    entry_SYSCALL_64_after_hwframe+0x76/0x7e
>>>   RIP: 0033:0x7262a6124ded
>>>   Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
>>>   RSP: 002b:00007fffd08c3960 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
>>>   RAX: ffffffffffffffda RBX: 00007fffd08c39f0 RCX: 00007262a6124ded
>>>   RDX: 00007fffd08c3a10 RSI: 00000000c0181b01 RDI: 0000000000000007
>>>   RBP: 00007fffd08c39b0 R08: 0000000014107820 R09: 00007fffd08c3b44
>>>   R10: 000000000000000c R11: 0000000000000246 R12: 00007fffd08c3b44
>>>   R13: 000000000000000c R14: 00007fffd08c3b58 R15: 0000000014107960
>>>    </TASK>
>>>
>>> Fixes: 1efe8c0670d6 ("RDMA/core: Convert UMEM ODP DMA mapping to caching IOVA and page linkage")
>>> Closes: https://lore.kernel.org/ all/3e8f343f-7d66-4f7a-9f08-3910623e322f@gmail.com/
>>> Signed-off-by: Daisuke Matsuda <dskmtsd@gmail.com>
>>> ---
>>>   drivers/infiniband/core/device.c   | 24 ++++++++++++++++++++++++
>>>   drivers/infiniband/core/umem_odp.c |  6 +++---
>>>   include/rdma/ib_verbs.h            | 12 ++++++++++++
>>>   3 files changed, 39 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/ core/device.c
>>> index b4e3e4beb7f4..8be4797c66ec 100644
>>> --- a/drivers/infiniband/core/device.c
>>> +++ b/drivers/infiniband/core/device.c
>>> @@ -2864,6 +2864,30 @@ int ib_dma_virt_map_sg(struct ib_device *dev, struct scatterlist *sg, int nents)
>>>       return nents;
>>>   }
>>>   EXPORT_SYMBOL(ib_dma_virt_map_sg);
>>> +int ib_dma_virt_map_alloc(struct device *dev, struct hmm_dma_map *map,
>>> +              size_t nr_entries, size_t dma_entry_size)
>>> +{
>>> +    if (!(nr_entries * PAGE_SIZE / dma_entry_size))
>>> +        return -EINVAL;
>>> +
>>> +    map->dma_entry_size = dma_entry_size;
>>> +    map->pfn_list = kvcalloc(nr_entries, sizeof(*map->pfn_list),
>>> +                 GFP_KERNEL | __GFP_NOWARN);
>>> +    if (!map->pfn_list)
>>> +        return -ENOMEM;
>>> +
>>> +    map->dma_list = kvcalloc(nr_entries, sizeof(*map->dma_list),
>>> +                 GFP_KERNEL | __GFP_NOWARN);
>>> +    if (!map->dma_list)
>>> +        goto err_dma;
>>> +
>>> +    return 0;
>>> +
>>> +err_dma:
>>> +    kvfree(map->pfn_list);
>>> +    return -ENOMEM;
>>> +}
>>> +EXPORT_SYMBOL(ib_dma_virt_map_alloc);
>>>   #endif /* CONFIG_INFINIBAND_VIRT_DMA */
>>>   static const struct rdma_nl_cbs ibnl_ls_cb_table[RDMA_NL_LS_NUM_OPS] = {
>>> diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/ core/umem_odp.c
>>> index 51d518989914..aa03f3fc84d0 100644
>>> --- a/drivers/infiniband/core/umem_odp.c
>>> +++ b/drivers/infiniband/core/umem_odp.c
>>> @@ -75,9 +75,9 @@ static int ib_init_umem_odp(struct ib_umem_odp *umem_odp,
>>>       if (unlikely(end < page_size))
>>>           return -EOVERFLOW;
>>> -    ret = hmm_dma_map_alloc(dev->dma_device, &umem_odp->map,
>>> -                (end - start) >> PAGE_SHIFT,
>>> -                1 << umem_odp->page_shift);
>>> +    ret = ib_dma_map_alloc(dev, &umem_odp->map,
>>> +                   (end - start) >> PAGE_SHIFT,
>>> +                   1 << umem_odp->page_shift);
>>>       if (ret)
>>>           return ret;
>>> diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
>>> index b06a0ed81bdd..10813f348b99 100644
>>> --- a/include/rdma/ib_verbs.h
>>> +++ b/include/rdma/ib_verbs.h
>>> @@ -36,6 +36,7 @@
>>>   #include <linux/irqflags.h>
>>>   #include <linux/preempt.h>
>>>   #include <linux/dim.h>
>>> +#include <linux/hmm-dma.h>
>>>   #include <uapi/rdma/ib_user_verbs.h>
>>>   #include <rdma/rdma_counter.h>
>>>   #include <rdma/restrack.h>
>>> @@ -4221,6 +4222,17 @@ static inline void ib_dma_unmap_sg_attrs(struct ib_device *dev,
>>>                      dma_attrs);
>>>   }
>>> +int ib_dma_virt_map_alloc(struct device *dev, struct hmm_dma_map *map,
>>> +              size_t nr_entries, size_t dma_entry_size);
>>> +static inline int ib_dma_map_alloc(struct ib_device *dev, struct hmm_dma_map *map,
>>> +                   size_t nr_entries, size_t dma_entry_size)
>>> +{
>>> +    if (ib_uses_virt_dma(dev))
>>> +        return ib_dma_virt_map_alloc(dev->dma_device, map, nr_entries,
>>> +                         dma_entry_size);
>>
>> Other emulated RDMA devices driver also call ib_dma_virt_map_alloc?
>> Only rxe will call ib_dma_virt_map_alloc?

Only rxe will call ib_dma_virt_map_alloc()
because currently only mlx5 and rxe will use ib_dma_map_alloc().

> 
> As I know, other emulated RDMA driver also implemented ODP, and with the current hmm_dma_map_alloc, it can work well.
> So in the above "if (ib_uses_virt_dma(dev))", changed to if (rxe_dev), then go to call ib_dma_virt_map_alloc.

Only mlx5 and rxe support ODP. While hmm_dma_map_alloc() works fine for mlx5,
it cannot be used for any drivers under drivers/infiniband/sw/ because they all set
dma_device to NULL in ib_register_device().

So changing the condition to if (rxe_dev) makes the code too specific.
To my understanding, it's generally discouraged to add code in the RDMA core
that targets a specific implementation.

I have just realized that we can remove an argument "struct device"
from ib_dma_virt_map_alloc(). I will post the v2 to fix this.

Thanks,
Daisuke

> 
> Yanjun.Zhu
> 
>>
>> Zhu Yanjun
>>
>>> +    return hmm_dma_map_alloc(dev->dma_device, map, nr_entries, dma_entry_size);
>>> +}
>>> +
>>>   /**
>>>    * ib_dma_map_sgtable_attrs - Map a scatter/gather table to DMA addresses
>>>    * @dev: The device for which the DMA addresses are to be created
>>
>

Re: [PATCH for-next v1] RDMA/core: Avoid hmm_dma_map_alloc() for virtual DMA devices

Posted by Zhu Yanjun 6 months, 3 weeks ago

在 2025/5/24 15:15, Daisuke Matsuda 写道:
> 
> On 2025/05/24 16:52, Zhu Yanjun wrote:
>> 在 2025/5/24 9:31, Zhu Yanjun 写道:
>>> 在 2025/5/23 20:47, Daisuke Matsuda 写道:
>>>> Drivers such as rxe, which use virtual DMA, must not call into the DMA
>>>> mapping core since they lack physical DMA capabilities. Otherwise, a 
>>>> NULL
>>>> pointer dereference is observed as shown below. This patch ensures 
>>>> the RDMA
>>>> core handles virtual and physical DMA paths appropriately.
>>>>
>>>> This fixes the following kernel oops:
>>>>
>>>>   BUG: kernel NULL pointer dereference, address: 00000000000002fc
>>>>   #PF: supervisor read access in kernel mode
>>>>   #PF: error_code(0x0000) - not-present page
>>>>   PGD 1028eb067 P4D 1028eb067 PUD 105da0067 PMD 0
>>>>   Oops: Oops: 0000 [#1] SMP NOPTI
>>>>   CPU: 3 UID: 1000 PID: 1854 Comm: python3 Tainted: G W           
>>>> 6.15.0-rc1+ #11 PREEMPT(voluntary)
>>>>   Tainted: [W]=WARN
>>>>   Hardware name: Trigkey Key N/Key N, BIOS KEYN101 09/02/2024
>>>>   RIP: 0010:hmm_dma_map_alloc+0x25/0x100
>>>>   Code: 90 90 90 90 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 49 89 
>>>> d6 49 c1 e6 0c 41 55 41 54 53 49 39 ce 0f 82 c6 00 00 00 49 89 fc 
>>>> <f6> 87 fc 02 00 00 20 0f 84 af 00 00 00 49 89 f5 48 89 d3 49 89 cf
>>>>   RSP: 0018:ffffd3d3420eb830 EFLAGS: 00010246
>>>>   RAX: 0000000000001000 RBX: ffff8b727c7f7400 RCX: 0000000000001000
>>>>   RDX: 0000000000000001 RSI: ffff8b727c7f74b0 RDI: 0000000000000000
>>>>   RBP: ffffd3d3420eb858 R08: 0000000000000000 R09: 0000000000000000
>>>>   R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
>>>>   R13: 00007262a622a000 R14: 0000000000001000 R15: ffff8b727c7f74b0
>>>>   FS:  00007262a62a1080(0000) GS:ffff8b762ac3e000(0000) 
>>>> knlGS:0000000000000000
>>>>   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>>>   CR2: 00000000000002fc CR3: 000000010a1f0004 CR4: 0000000000f72ef0
>>>>   PKRU: 55555554
>>>>   Call Trace:
>>>>    <TASK>
>>>>    ib_init_umem_odp+0xb6/0x110 [ib_uverbs]
>>>>    ib_umem_odp_get+0xf0/0x150 [ib_uverbs]
>>>>    rxe_odp_mr_init_user+0x71/0x170 [rdma_rxe]
>>>>    rxe_reg_user_mr+0x217/0x2e0 [rdma_rxe]
>>>>    ib_uverbs_reg_mr+0x19e/0x2e0 [ib_uverbs]
>>>>    ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0xd9/0x150 [ib_uverbs]
>>>>    ib_uverbs_cmd_verbs+0xd19/0xee0 [ib_uverbs]
>>>>    ? mmap_region+0x63/0xd0
>>>>    ? __pfx_ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0x10/0x10 
>>>> [ib_uverbs]
>>>>    ib_uverbs_ioctl+0xba/0x130 [ib_uverbs]
>>>>    __x64_sys_ioctl+0xa4/0xe0
>>>>    x64_sys_call+0x1178/0x2660
>>>>    do_syscall_64+0x7e/0x170
>>>>    ? syscall_exit_to_user_mode+0x4e/0x250
>>>>    ? do_syscall_64+0x8a/0x170
>>>>    ? do_syscall_64+0x8a/0x170
>>>>    ? syscall_exit_to_user_mode+0x4e/0x250
>>>>    ? do_syscall_64+0x8a/0x170
>>>>    ? syscall_exit_to_user_mode+0x4e/0x250
>>>>    ? do_syscall_64+0x8a/0x170
>>>>    ? do_user_addr_fault+0x1d2/0x8d0
>>>>    ? irqentry_exit_to_user_mode+0x43/0x250
>>>>    ? irqentry_exit+0x43/0x50
>>>>    ? exc_page_fault+0x93/0x1d0
>>>>    entry_SYSCALL_64_after_hwframe+0x76/0x7e
>>>>   RIP: 0033:0x7262a6124ded
>>>>   Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 
>>>> 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 
>>>> <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
>>>>   RSP: 002b:00007fffd08c3960 EFLAGS: 00000246 ORIG_RAX: 
>>>> 0000000000000010
>>>>   RAX: ffffffffffffffda RBX: 00007fffd08c39f0 RCX: 00007262a6124ded
>>>>   RDX: 00007fffd08c3a10 RSI: 00000000c0181b01 RDI: 0000000000000007
>>>>   RBP: 00007fffd08c39b0 R08: 0000000014107820 R09: 00007fffd08c3b44
>>>>   R10: 000000000000000c R11: 0000000000000246 R12: 00007fffd08c3b44
>>>>   R13: 000000000000000c R14: 00007fffd08c3b58 R15: 0000000014107960
>>>>    </TASK>
>>>>
>>>> Fixes: 1efe8c0670d6 ("RDMA/core: Convert UMEM ODP DMA mapping to 
>>>> caching IOVA and page linkage")
>>>> Closes: https://lore.kernel.org/ 
>>>> all/3e8f343f-7d66-4f7a-9f08-3910623e322f@gmail.com/
>>>> Signed-off-by: Daisuke Matsuda <dskmtsd@gmail.com>
>>>> ---
>>>>   drivers/infiniband/core/device.c   | 24 ++++++++++++++++++++++++
>>>>   drivers/infiniband/core/umem_odp.c |  6 +++---
>>>>   include/rdma/ib_verbs.h            | 12 ++++++++++++
>>>>   3 files changed, 39 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/ 
>>>> core/device.c
>>>> index b4e3e4beb7f4..8be4797c66ec 100644
>>>> --- a/drivers/infiniband/core/device.c
>>>> +++ b/drivers/infiniband/core/device.c
>>>> @@ -2864,6 +2864,30 @@ int ib_dma_virt_map_sg(struct ib_device *dev, 
>>>> struct scatterlist *sg, int nents)
>>>>       return nents;
>>>>   }
>>>>   EXPORT_SYMBOL(ib_dma_virt_map_sg);
>>>> +int ib_dma_virt_map_alloc(struct device *dev, struct hmm_dma_map *map,
>>>> +              size_t nr_entries, size_t dma_entry_size)
>>>> +{
>>>> +    if (!(nr_entries * PAGE_SIZE / dma_entry_size))
>>>> +        return -EINVAL;
>>>> +
>>>> +    map->dma_entry_size = dma_entry_size;
>>>> +    map->pfn_list = kvcalloc(nr_entries, sizeof(*map->pfn_list),
>>>> +                 GFP_KERNEL | __GFP_NOWARN);
>>>> +    if (!map->pfn_list)
>>>> +        return -ENOMEM;
>>>> +
>>>> +    map->dma_list = kvcalloc(nr_entries, sizeof(*map->dma_list),
>>>> +                 GFP_KERNEL | __GFP_NOWARN);
>>>> +    if (!map->dma_list)
>>>> +        goto err_dma;
>>>> +
>>>> +    return 0;
>>>> +
>>>> +err_dma:
>>>> +    kvfree(map->pfn_list);
>>>> +    return -ENOMEM;
>>>> +}
>>>> +EXPORT_SYMBOL(ib_dma_virt_map_alloc);
>>>>   #endif /* CONFIG_INFINIBAND_VIRT_DMA */
>>>>   static const struct rdma_nl_cbs 
>>>> ibnl_ls_cb_table[RDMA_NL_LS_NUM_OPS] = {
>>>> diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/ 
>>>> infiniband/ core/umem_odp.c
>>>> index 51d518989914..aa03f3fc84d0 100644
>>>> --- a/drivers/infiniband/core/umem_odp.c
>>>> +++ b/drivers/infiniband/core/umem_odp.c
>>>> @@ -75,9 +75,9 @@ static int ib_init_umem_odp(struct ib_umem_odp 
>>>> *umem_odp,
>>>>       if (unlikely(end < page_size))
>>>>           return -EOVERFLOW;
>>>> -    ret = hmm_dma_map_alloc(dev->dma_device, &umem_odp->map,
>>>> -                (end - start) >> PAGE_SHIFT,
>>>> -                1 << umem_odp->page_shift);
>>>> +    ret = ib_dma_map_alloc(dev, &umem_odp->map,
>>>> +                   (end - start) >> PAGE_SHIFT,
>>>> +                   1 << umem_odp->page_shift);
>>>>       if (ret)
>>>>           return ret;
>>>> diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
>>>> index b06a0ed81bdd..10813f348b99 100644
>>>> --- a/include/rdma/ib_verbs.h
>>>> +++ b/include/rdma/ib_verbs.h
>>>> @@ -36,6 +36,7 @@
>>>>   #include <linux/irqflags.h>
>>>>   #include <linux/preempt.h>
>>>>   #include <linux/dim.h>
>>>> +#include <linux/hmm-dma.h>
>>>>   #include <uapi/rdma/ib_user_verbs.h>
>>>>   #include <rdma/rdma_counter.h>
>>>>   #include <rdma/restrack.h>
>>>> @@ -4221,6 +4222,17 @@ static inline void 
>>>> ib_dma_unmap_sg_attrs(struct ib_device *dev,
>>>>                      dma_attrs);
>>>>   }
>>>> +int ib_dma_virt_map_alloc(struct device *dev, struct hmm_dma_map *map,
>>>> +              size_t nr_entries, size_t dma_entry_size);
>>>> +static inline int ib_dma_map_alloc(struct ib_device *dev, struct 
>>>> hmm_dma_map *map,
>>>> +                   size_t nr_entries, size_t dma_entry_size)
>>>> +{
>>>> +    if (ib_uses_virt_dma(dev))
>>>> +        return ib_dma_virt_map_alloc(dev->dma_device, map, nr_entries,
>>>> +                         dma_entry_size);
>>>
>>> Other emulated RDMA devices driver also call ib_dma_virt_map_alloc?
>>> Only rxe will call ib_dma_virt_map_alloc?
> 
> Only rxe will call ib_dma_virt_map_alloc()
> because currently only mlx5 and rxe will use ib_dma_map_alloc().
> 
>>
>> As I know, other emulated RDMA driver also implemented ODP, and with 
>> the current hmm_dma_map_alloc, it can work well.
>> So in the above "if (ib_uses_virt_dma(dev))", changed to if (rxe_dev), 
>> then go to call ib_dma_virt_map_alloc.
> 
> Only mlx5 and rxe support ODP. While hmm_dma_map_alloc() works fine for 
> mlx5,

No. Other private emulated RDMA driver also supports ODP, but it is not 
in the directory drivers/infiniband/sw/. It also call ib_dma_map_alloc 
and works well with hmm_dma_map_alloc.

Up to you because the driver is not in kernel. I do not have strong 
preference.

> it cannot be used for any drivers under drivers/infiniband/sw/ because 
> they all set
> dma_device to NULL in ib_register_device().
> 
> So changing the condition to if (rxe_dev) makes the code too specific.
> To my understanding, it's generally discouraged to add code in the RDMA 
> core
> that targets a specific implementation.
> 
> I have just realized that we can remove an argument "struct device"
> from ib_dma_virt_map_alloc(). I will post the v2 to fix this.

Please go ahead.

Zhu Yanjun

> 
> Thanks,
> Daisuke
> 
>>
>> Yanjun.Zhu
>>
>>>
>>> Zhu Yanjun
>>>
>>>> +    return hmm_dma_map_alloc(dev->dma_device, map, nr_entries, 
>>>> dma_entry_size);
>>>> +}
>>>> +
>>>>   /**
>>>>    * ib_dma_map_sgtable_attrs - Map a scatter/gather table to DMA 
>>>> addresses
>>>>    * @dev: The device for which the DMA addresses are to be created
>>>
>>
>