[PATCH -fixes v2] riscv: Fix wrong usage of lm_alias() when splitting a huge linear mapping

[PATCH -fixes v2] riscv: Fix wrong usage of lm_alias() when splitting a huge linear mapping

[Alexandre Ghiti]

lm_alias() can only be used on kernel mappings since it explicitly uses
__pa_symbol(), so simply fix this by checking where the address belongs
to before.

Fixes: 311cd2f6e253 ("riscv: Fix set_memory_XX() and set_direct_map_XX() by splitting huge linear mappings")
Reported-by: syzbot+afb726d49f84c8d95ee1@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-riscv/000000000000620dd0060c02c5e1@google.com/
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---

Changes in v2:
- Fix llvm warning about unitialized return value

 arch/riscv/mm/pageattr.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/mm/pageattr.c b/arch/riscv/mm/pageattr.c
index fc5fc4f785c4..96cbda683936 100644
--- a/arch/riscv/mm/pageattr.c
+++ b/arch/riscv/mm/pageattr.c
@@ -305,8 +305,13 @@ static int __set_memory(unsigned long addr, int numpages, pgprot_t set_mask,
 				goto unlock;
 		}
 	} else if (is_kernel_mapping(start) || is_linear_mapping(start)) {
-		lm_start = (unsigned long)lm_alias(start);
-		lm_end = (unsigned long)lm_alias(end);
+		if (is_kernel_mapping(start)) {
+			lm_start = (unsigned long)lm_alias(start);
+			lm_end = (unsigned long)lm_alias(end);
+		} else {
+			lm_start = start;
+			lm_end = end;
+		}
 
 		ret = split_linear_mapping(lm_start, lm_end);
 		if (ret)
-- 
2.39.2

Re: [PATCH -fixes v2] riscv: Fix wrong usage of lm_alias() when splitting a huge linear mapping

[Charlie Jenkins]

On Tue, Dec 12, 2023 at 08:54:00PM +0100, Alexandre Ghiti wrote:
> lm_alias() can only be used on kernel mappings since it explicitly uses
> __pa_symbol(), so simply fix this by checking where the address belongs
> to before.
> 
> Fixes: 311cd2f6e253 ("riscv: Fix set_memory_XX() and set_direct_map_XX() by splitting huge linear mappings")
> Reported-by: syzbot+afb726d49f84c8d95ee1@syzkaller.appspotmail.com
> Closes: https://lore.kernel.org/linux-riscv/000000000000620dd0060c02c5e1@google.com/
> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> ---
> 
> Changes in v2:
> - Fix llvm warning about unitialized return value
> 
>  arch/riscv/mm/pageattr.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/riscv/mm/pageattr.c b/arch/riscv/mm/pageattr.c
> index fc5fc4f785c4..96cbda683936 100644
> --- a/arch/riscv/mm/pageattr.c
> +++ b/arch/riscv/mm/pageattr.c
> @@ -305,8 +305,13 @@ static int __set_memory(unsigned long addr, int numpages, pgprot_t set_mask,
>  				goto unlock;
>  		}
>  	} else if (is_kernel_mapping(start) || is_linear_mapping(start)) {
> -		lm_start = (unsigned long)lm_alias(start);
> -		lm_end = (unsigned long)lm_alias(end);
> +		if (is_kernel_mapping(start)) {
> +			lm_start = (unsigned long)lm_alias(start);
> +			lm_end = (unsigned long)lm_alias(end);
> +		} else {
> +			lm_start = start;
> +			lm_end = end;
> +		}
>  
>  		ret = split_linear_mapping(lm_start, lm_end);
>  		if (ret)
> -- 
> 2.39.2

Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>

> 
> 
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

Re: [PATCH -fixes v2] riscv: Fix wrong usage of lm_alias() when splitting a huge linear mapping

[patchwork-bot+linux-riscv]

Hello:

This patch was applied to riscv/linux.git (fixes)
by Palmer Dabbelt <palmer@rivosinc.com>:

On Tue, 12 Dec 2023 20:54:00 +0100 you wrote:
> lm_alias() can only be used on kernel mappings since it explicitly uses
> __pa_symbol(), so simply fix this by checking where the address belongs
> to before.
> 
> Fixes: 311cd2f6e253 ("riscv: Fix set_memory_XX() and set_direct_map_XX() by splitting huge linear mappings")
> Reported-by: syzbot+afb726d49f84c8d95ee1@syzkaller.appspotmail.com
> Closes: https://lore.kernel.org/linux-riscv/000000000000620dd0060c02c5e1@google.com/
> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> 
> [...]

Here is the summary with links:
  - [-fixes,v2] riscv: Fix wrong usage of lm_alias() when splitting a huge linear mapping
    https://git.kernel.org/riscv/c/6af3dd2be9cc

You are awesome, thank you!
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