The hardware provides the indexes of the first and the last available
queue and VF. From the indexes, the driver calculates the numbers of
queues and VFs. In theory, a faulty device might say the last index is
smaller than the first index. In that case, the driver's calculation
would underflow, it would attempt to write to non-existent registers
outside of the ioremapped range and crash.
I ran into this not by having a faulty device, but by an operator error.
I accidentally ran a QE test meant for i40e devices on an ice device.
The test used 'echo i40e > /sys/...ice PCI device.../driver_override',
bound the driver to the device and crashed in one of the wr32 calls in
i40e_clear_hw.
Add checks to prevent underflows in the calculations of num_queues and
num_vfs. With this fix, the wrong device probing reports errors and
returns a failure without crashing.
Fixes: 838d41d92a90 ("i40e: clear all queues and interrupts")
Signed-off-by: Michal Schmidt <mschm...@redhat.com>
---
drivers/net/ethernet/intel/i40e/i40e_common.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/intel/i40e/i40e_common.c
b/drivers/net/ethernet/intel/i40e/i40e_common.c
index eeef20f77106..1b493854f522 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_common.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_common.c
@@ -1082,7 +1082,7 @@ void i40e_clear_hw(struct i40e_hw *hw)
I40E_PFLAN_QALLOC_FIRSTQ_SHIFT;
j = (val & I40E_PFLAN_QALLOC_LASTQ_MASK) >>
I40E_PFLAN_QALLOC_LASTQ_SHIFT;
- if (val & I40E_PFLAN_QALLOC_VALID_MASK)
+ if (val & I40E_PFLAN_QALLOC_VALID_MASK && j >= base_queue)
num_queues = (j - base_queue) + 1;
else
num_queues = 0;
@@ -1092,7 +1092,7 @@ void i40e_clear_hw(struct i40e_hw *hw)
I40E_PF_VT_PFALLOC_FIRSTVF_SHIFT;
j = (val & I40E_PF_VT_PFALLOC_LASTVF_MASK) >>
I40E_PF_VT_PFALLOC_LASTVF_SHIFT;
- if (val & I40E_PF_VT_PFALLOC_VALID_MASK)
+ if (val & I40E_PF_VT_PFALLOC_VALID_MASK && j >= i)
num_vfs = (j - i) + 1;
else
num_vfs = 0;
--
2.41.0
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