2019-10-29 01:02:03

by Xiang Zheng

Subject: [PATCH] arm64: print additional fault message when executing non-exec memory

When attempting to executing non-executable memory, the fault message
shows:

Unable to handle kernel read from unreadable memory at virtual address
ffff802dac469000

This may confuse someone, so add a new fault message for instruction
abort.

Signed-off-by: Xiang Zheng <[email protected]>
---
arch/arm64/mm/fault.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 9fc6db0bcbad..68bf4ec376d0 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -318,6 +318,8 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr,
if (is_el1_permission_fault(addr, esr, regs)) {
if (esr & ESR_ELx_WNR)
msg = "write to read-only memory";
+ else if (is_el1_instruction_abort(esr))
+ msg = "execute non-executable memory";
else
msg = "read from unreadable memory";
} else if (addr < PAGE_SIZE) {
--
2.19.1

2019-10-29 06:13:29

by Will Deacon

Subject: Re: [PATCH] arm64: print additional fault message when executing non-exec memory

On Mon, Oct 28, 2019 at 05:08:37PM +0800, Xiang Zheng wrote:
> When attempting to executing non-executable memory, the fault message
> shows:
>
> Unable to handle kernel read from unreadable memory at virtual address
> ffff802dac469000
>
> This may confuse someone, so add a new fault message for instruction
> abort.
>
> Signed-off-by: Xiang Zheng <[email protected]>
> ---
> arch/arm64/mm/fault.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
> index 9fc6db0bcbad..68bf4ec376d0 100644
> --- a/arch/arm64/mm/fault.c
> +++ b/arch/arm64/mm/fault.c
> @@ -318,6 +318,8 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr,
> if (is_el1_permission_fault(addr, esr, regs)) {
> if (esr & ESR_ELx_WNR)
> msg = "write to read-only memory";
> + else if (is_el1_instruction_abort(esr))
> + msg = "execute non-executable memory";

nit, please make this "execute from non-executable memory".

With that:

Acked-by: Will Deacon <[email protected]>

Will

2019-10-29 09:20:01

by Xiang Zheng

Subject: Re: [PATCH] arm64: print additional fault message when executing non-exec memory

On 2019/10/29 0:41, Will Deacon wrote:
> On Mon, Oct 28, 2019 at 05:08:37PM +0800, Xiang Zheng wrote:
>> When attempting to executing non-executable memory, the fault message
>> shows:
>>
>> Unable to handle kernel read from unreadable memory at virtual address
>> ffff802dac469000
>>
>> This may confuse someone, so add a new fault message for instruction
>> abort.
>>
>> Signed-off-by: Xiang Zheng <[email protected]>
>> ---
>> arch/arm64/mm/fault.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
>> index 9fc6db0bcbad..68bf4ec376d0 100644
>> --- a/arch/arm64/mm/fault.c
>> +++ b/arch/arm64/mm/fault.c
>> @@ -318,6 +318,8 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr,
>> if (is_el1_permission_fault(addr, esr, regs)) {
>> if (esr & ESR_ELx_WNR)
>> msg = "write to read-only memory";
>> + else if (is_el1_instruction_abort(esr))
>> + msg = "execute non-executable memory";
>
> nit, please make this "execute from non-executable memory".

Thanks, I will make this in the next version of patch.

>
> With that:
>
> Acked-by: Will Deacon <[email protected]>
>
> Will
>
> .
>

--

Thanks,
Xiang