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[PATCH v11 01/11] riscv: kexec_file: Fix crashk_low_res not exclude bug

Jinjie Ruan posted 11 patches 4 days, 18 hours ago
[PATCH v11 01/11] riscv: kexec_file: Fix crashk_low_res not exclude bug
Posted by Jinjie Ruan 4 days, 18 hours ago 
As done in commit 944a45abfabc ("arm64: kdump: Reimplement crashkernel=X")
and commit 4831be702b95 ("arm64/kexec: Fix missing extra range for
crashkres_low.") for arm64, while implementing crashkernel=X,[high,low],
riscv should have excluded the "crashk_low_res" reserved ranges from
the crash kernel memory to prevent them from being exported through
/proc/vmcore, and the exclusion would need an extra crash_mem range.

Cc: Guo Ren <guoren@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Fixes: 5882e5acf18d ("riscv: kdump: Implement crashkernel=X,[high,low]")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
---
 arch/riscv/kernel/machine_kexec_file.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/kernel/machine_kexec_file.c b/arch/riscv/kernel/machine_kexec_file.c
index 54e2d9552e93..3f7766057cac 100644
--- a/arch/riscv/kernel/machine_kexec_file.c
+++ b/arch/riscv/kernel/machine_kexec_file.c
@@ -61,7 +61,7 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
 	unsigned int nr_ranges;
 	int ret;
 
-	nr_ranges = 1; /* For exclusion of crashkernel region */
+	nr_ranges = 2; /* For exclusion of crashkernel region */
 	walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);
 
 	cmem = kmalloc_flex(*cmem, ranges, nr_ranges);
@@ -76,8 +76,16 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
 
 	/* Exclude crashkernel region */
 	ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
-	if (!ret)
-		ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
+	if (ret)
+		goto out;
+
+	if (crashk_low_res.end) {
+		ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
+		if (ret)
+			goto out;
+	}
+
+	ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
 
 out:
 	kfree(cmem);
-- 
2.34.1
Re: [PATCH v11 01/11] riscv: kexec_file: Fix crashk_low_res not exclude bug
Posted by Guo Ren 2 days, 22 hours ago 
On Sat, Mar 28, 2026 at 3:41 PM Jinjie Ruan <ruanjinjie@huawei.com> wrote:
>
> As done in commit 944a45abfabc ("arm64: kdump: Reimplement crashkernel=X")
> and commit 4831be702b95 ("arm64/kexec: Fix missing extra range for
> crashkres_low.") for arm64, while implementing crashkernel=X,[high,low],
> riscv should have excluded the "crashk_low_res" reserved ranges from
> the crash kernel memory to prevent them from being exported through
> /proc/vmcore, and the exclusion would need an extra crash_mem range.
>
> Cc: Guo Ren <guoren@kernel.org>
> Cc: Baoquan He <bhe@redhat.com>
> Fixes: 5882e5acf18d ("riscv: kdump: Implement crashkernel=X,[high,low]")
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
> ---
>  arch/riscv/kernel/machine_kexec_file.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/arch/riscv/kernel/machine_kexec_file.c b/arch/riscv/kernel/machine_kexec_file.c
> index 54e2d9552e93..3f7766057cac 100644
> --- a/arch/riscv/kernel/machine_kexec_file.c
> +++ b/arch/riscv/kernel/machine_kexec_file.c
> @@ -61,7 +61,7 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
>         unsigned int nr_ranges;
>         int ret;
>
> -       nr_ranges = 1; /* For exclusion of crashkernel region */
> +       nr_ranges = 2; /* For exclusion of crashkernel region */
>         walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);
>
>         cmem = kmalloc_flex(*cmem, ranges, nr_ranges);
> @@ -76,8 +76,16 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
>
>         /* Exclude crashkernel region */
>         ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
> -       if (!ret)
> -               ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
> +       if (ret)
> +               goto out;
> +
> +       if (crashk_low_res.end) {
> +               ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
Exclude crashk_low_res is reasonable, but have you tested this?

> +               if (ret)
> +                       goto out;
> +       }
> +
> +       ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
>
>  out:
>         kfree(cmem);
> --
> 2.34.1
>


-- 
Best Regards
 Guo Ren
Re: [PATCH v11 01/11] riscv: kexec_file: Fix crashk_low_res not exclude bug
Posted by Jinjie Ruan 2 days, 18 hours ago 

On 2026/3/30 11:49, Guo Ren wrote:
> On Sat, Mar 28, 2026 at 3:41 PM Jinjie Ruan <ruanjinjie@huawei.com> wrote:
>>
>> As done in commit 944a45abfabc ("arm64: kdump: Reimplement crashkernel=X")
>> and commit 4831be702b95 ("arm64/kexec: Fix missing extra range for
>> crashkres_low.") for arm64, while implementing crashkernel=X,[high,low],
>> riscv should have excluded the "crashk_low_res" reserved ranges from
>> the crash kernel memory to prevent them from being exported through
>> /proc/vmcore, and the exclusion would need an extra crash_mem range.
>>
>> Cc: Guo Ren <guoren@kernel.org>
>> Cc: Baoquan He <bhe@redhat.com>
>> Fixes: 5882e5acf18d ("riscv: kdump: Implement crashkernel=X,[high,low]")
>> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
>> ---
>>  arch/riscv/kernel/machine_kexec_file.c | 14 +++++++++++---
>>  1 file changed, 11 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/riscv/kernel/machine_kexec_file.c b/arch/riscv/kernel/machine_kexec_file.c
>> index 54e2d9552e93..3f7766057cac 100644
>> --- a/arch/riscv/kernel/machine_kexec_file.c
>> +++ b/arch/riscv/kernel/machine_kexec_file.c
>> @@ -61,7 +61,7 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
>>         unsigned int nr_ranges;
>>         int ret;
>>
>> -       nr_ranges = 1; /* For exclusion of crashkernel region */
>> +       nr_ranges = 2; /* For exclusion of crashkernel region */
>>         walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);
>>
>>         cmem = kmalloc_flex(*cmem, ranges, nr_ranges);
>> @@ -76,8 +76,16 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
>>
>>         /* Exclude crashkernel region */
>>         ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
>> -       if (!ret)
>> -               ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
>> +       if (ret)
>> +               goto out;
>> +
>> +       if (crashk_low_res.end) {
>> +               ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
> Exclude crashk_low_res is reasonable, but have you tested this?

Just simply tested on qemu with crashkernel=4G with following kexec
mentioned in
https://lore.kernel.org/all/20230726175000.2536220-1-chenjiahao16@huawei.com/.
And the second kernel can be started normally.

https://github.com/chenjh005/kexec-tools/tree/build-test-riscv-v2

# dmesg | grep crash
[    0.000000] crashkernel low memory reserved: 0xf8000000 - 0x100000000
(128 MB)
[    0.000000] crashkernel reserved: 0x000000017fe00000 -
0x000000027fe00000 (4096 MB)



> 
>> +               if (ret)
>> +                       goto out;
>> +       }
>> +
>> +       ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
>>
>>  out:
>>         kfree(cmem);
>> --
>> 2.34.1
>>
> 
>
Re: [PATCH v11 01/11] riscv: kexec_file: Fix crashk_low_res not exclude bug
Posted by Guo Ren 2 days, 18 hours ago 
On Mon, Mar 30, 2026 at 3:11 PM Jinjie Ruan <ruanjinjie@huawei.com> wrote:
>
>
>
> On 2026/3/30 11:49, Guo Ren wrote:
> > On Sat, Mar 28, 2026 at 3:41 PM Jinjie Ruan <ruanjinjie@huawei.com> wrote:
> >>
> >> As done in commit 944a45abfabc ("arm64: kdump: Reimplement crashkernel=X")
> >> and commit 4831be702b95 ("arm64/kexec: Fix missing extra range for
> >> crashkres_low.") for arm64, while implementing crashkernel=X,[high,low],
> >> riscv should have excluded the "crashk_low_res" reserved ranges from
> >> the crash kernel memory to prevent them from being exported through
> >> /proc/vmcore, and the exclusion would need an extra crash_mem range.
> >>
> >> Cc: Guo Ren <guoren@kernel.org>
> >> Cc: Baoquan He <bhe@redhat.com>
> >> Fixes: 5882e5acf18d ("riscv: kdump: Implement crashkernel=X,[high,low]")
> >> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
> >> ---
> >>  arch/riscv/kernel/machine_kexec_file.c | 14 +++++++++++---
> >>  1 file changed, 11 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/arch/riscv/kernel/machine_kexec_file.c b/arch/riscv/kernel/machine_kexec_file.c
> >> index 54e2d9552e93..3f7766057cac 100644
> >> --- a/arch/riscv/kernel/machine_kexec_file.c
> >> +++ b/arch/riscv/kernel/machine_kexec_file.c
> >> @@ -61,7 +61,7 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
> >>         unsigned int nr_ranges;
> >>         int ret;
> >>
> >> -       nr_ranges = 1; /* For exclusion of crashkernel region */
> >> +       nr_ranges = 2; /* For exclusion of crashkernel region */
> >>         walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);
> >>
> >>         cmem = kmalloc_flex(*cmem, ranges, nr_ranges);
> >> @@ -76,8 +76,16 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
> >>
> >>         /* Exclude crashkernel region */
> >>         ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
> >> -       if (!ret)
> >> -               ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
> >> +       if (ret)
> >> +               goto out;
> >> +
> >> +       if (crashk_low_res.end) {
> >> +               ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
> > Exclude crashk_low_res is reasonable, but have you tested this?
>
> Just simply tested on qemu with crashkernel=4G with following kexec
> mentioned in
> https://lore.kernel.org/all/20230726175000.2536220-1-chenjiahao16@huawei.com/.
> And the second kernel can be started normally.
>
> https://github.com/chenjh005/kexec-tools/tree/build-test-riscv-v2
>
> # dmesg | grep crash
> [    0.000000] crashkernel low memory reserved: 0xf8000000 - 0x100000000
> (128 MB)
> [    0.000000] crashkernel reserved: 0x000000017fe00000 -
> 0x000000027fe00000 (4096 MB)
Adding a test log to the commit log makes the patch more trustworthy.

Reviewed-by: Guo Ren <guoren@kernel.org>

>
>
>
> >
> >> +               if (ret)
> >> +                       goto out;
> >> +       }
> >> +
> >> +       ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
> >>
> >>  out:
> >>         kfree(cmem);
> >> --
> >> 2.34.1
> >>
> >
> >



-- 
Best Regards
 Guo Ren

Patchew 2.1-devel-ea86937

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