* [PATCH] iommu/riscv: check pte null pointer before use
@ 2025-08-05 10:17 Huang XianLiang
2025-08-05 11:17 ` Markus Elfring
0 siblings, 1 reply; 3+ messages in thread
From: Huang XianLiang @ 2025-08-05 10:17 UTC (permalink / raw)
To: tjeznach
Cc: joro, will, robin.murphy, paul.walmsley, palmer, aou, alex, iommu,
linux-riscv, linux-kernel, huangxianliang
The riscv_iommu_pte_fetch can return NULL when the provided iova is not
yet mapped, the caller should check if the returned pointer is NULL or
not, but riscv_iommu_iova_to_phys missed this, which will then lead to
a kernel panic.
This commit just check the pointer before using it to avoid the bug.
Now, when iova_to_phys is called with an unmapped iova, the kernel will
not crash here.
Signed-off-by: Huang XianLiang <huangxianliang@lanxincomputing.com>
---
drivers/iommu/riscv/iommu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iommu/riscv/iommu.c b/drivers/iommu/riscv/iommu.c
index 2d0d31ba2886..b0186faa0300 100644
--- a/drivers/iommu/riscv/iommu.c
+++ b/drivers/iommu/riscv/iommu.c
@@ -1283,7 +1283,7 @@ static phys_addr_t riscv_iommu_iova_to_phys(struct iommu_domain *iommu_domain,
unsigned long *ptr;
ptr = riscv_iommu_pte_fetch(domain, iova, &pte_size);
- if (_io_pte_none(*ptr) || !_io_pte_present(*ptr))
+ if (!ptr || _io_pte_none(*ptr) || !_io_pte_present(*ptr))
return 0;
return pfn_to_phys(__page_val_to_pfn(*ptr)) | (iova & (pte_size - 1));
--
2.34.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] iommu/riscv: check pte null pointer before use
2025-08-05 10:17 [PATCH] iommu/riscv: check pte null pointer before use Huang XianLiang
@ 2025-08-05 11:17 ` Markus Elfring
2025-08-06 10:13 ` XianLiang Huang
0 siblings, 1 reply; 3+ messages in thread
From: Markus Elfring @ 2025-08-05 11:17 UTC (permalink / raw)
To: Huang XianLiang, iommu, linux-riscv
Cc: LKML, Albert Ou, Alexandre Ghiti, Jörg Rödel,
Palmer Dabbelt, Paul Walmsley, Robin Murphy, Tomasz Jeznach,
Will Deacon
…
> This commit just check the pointer before using it to avoid the bug.
…
See also:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.16#n94
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.16#n145
Regards,
Markus
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Re: [PATCH] iommu/riscv: check pte null pointer before use
2025-08-05 11:17 ` Markus Elfring
@ 2025-08-06 10:13 ` XianLiang Huang
0 siblings, 0 replies; 3+ messages in thread
From: XianLiang Huang @ 2025-08-06 10:13 UTC (permalink / raw)
To: markus.elfring
Cc: alex, aou, huangxianliang, iommu, joro, linux-kernel, linux-riscv,
palmer, paul.walmsley, robin.murphy, tjeznach, will
Sure, will change to "Check the pointer before..." in a new version, thanks.
Regards,
XianLiang
^ permalink raw reply [flat|nested] 3+ messages in thread
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2025-08-05 10:17 [PATCH] iommu/riscv: check pte null pointer before use Huang XianLiang
2025-08-05 11:17 ` Markus Elfring
2025-08-06 10:13 ` XianLiang Huang
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