Re: [PATCH v7 4/8] crash: add phdr for possible CPUs in elfcorehdr
On 20/01/23 17:09, Laurent Dufour wrote: On 19/01/2023 19:29:52, Laurent Dufour wrote: On 15/01/2023 16:02:02, Sourabh Jain wrote: On architectures like PowerPC the crash notes are available for all possible CPUs. So let's populate the elfcorehdr for all possible CPUs having crash notes to avoid updating elfcorehdr during in-kernel crash update on CPU hotplug events. The similar technique is used in kexec-tool for kexec_load case. Signed-off-by: Sourabh Jain --- kernel/crash_core.c | 9 ++--- 1 file changed, 6 insertions(+), 3 deletions(-) This patch is not applying on ppc/next (53ab112a9508). As far as I could see, crash_prepare_elf64_headers() is defined in the file kernel/kexec_file.c and that's not recent, see babac4a84a88 (kexec_file, x86: move re-factored code to generic side, 2018-04-13) Am I missing something? My mistake, sounds that your series is based on top of the Eric's one (not yet upstream): https://lore.kernel.org/lkml/20230118213544.2128-1-eric.devol...@oracle.com/ Yes this patch series is dependent on the above patch series. In the next version I will share a git repo link that will have this patch series applied along with dependent patch series for easy try. - Sourabh
Re: [PATCH v7 4/8] crash: add phdr for possible CPUs in elfcorehdr
On 19/01/2023 19:29:52, Laurent Dufour wrote:
> On 15/01/2023 16:02:02, Sourabh Jain wrote:
>> On architectures like PowerPC the crash notes are available for all
>> possible CPUs. So let's populate the elfcorehdr for all possible
>> CPUs having crash notes to avoid updating elfcorehdr during in-kernel
>> crash update on CPU hotplug events.
>>
>> The similar technique is used in kexec-tool for kexec_load case.
>>
>> Signed-off-by: Sourabh Jain
>> ---
>> kernel/crash_core.c | 9 ++---
>> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> This patch is not applying on ppc/next (53ab112a9508).
>
> As far as I could see, crash_prepare_elf64_headers() is defined in the file
> kernel/kexec_file.c and that's not recent, see babac4a84a88 (kexec_file,
> x86: move re-factored code to generic side, 2018-04-13)
>
> Am I missing something?
My mistake, sounds that your series is based on top of the Eric's one (not yet
upstream):
https://lore.kernel.org/lkml/20230118213544.2128-1-eric.devol...@oracle.com/
>
>>
>> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
>> index 910d377ea317e..19f987b3851e8 100644
>> --- a/kernel/crash_core.c
>> +++ b/kernel/crash_core.c
>> @@ -364,8 +364,8 @@ int crash_prepare_elf64_headers(struct kimage *image,
>> struct crash_mem *mem,
>> ehdr->e_ehsize = sizeof(Elf64_Ehdr);
>> ehdr->e_phentsize = sizeof(Elf64_Phdr);
>>
>> -/* Prepare one phdr of type PT_NOTE for each present CPU */
>> -for_each_present_cpu(cpu) {
>> +/* Prepare one phdr of type PT_NOTE for possible CPU with crash note. */
>> +for_each_possible_cpu(cpu) {
>> #ifdef CONFIG_CRASH_HOTPLUG
>> if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
>> /* Skip the soon-to-be offlined cpu */
>> @@ -373,8 +373,11 @@ int crash_prepare_elf64_headers(struct kimage *image,
>> struct crash_mem *mem,
>> continue;
>> }
>> #endif
>> -phdr->p_type = PT_NOTE;
>> notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
>> +if (!notes_addr)
>> +continue;
>> +
>> +phdr->p_type = PT_NOTE;
>> phdr->p_offset = phdr->p_paddr = notes_addr;
>> phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
>> (ehdr->e_phnum)++;
>
Re: [PATCH v7 4/8] crash: add phdr for possible CPUs in elfcorehdr
On 15/01/2023 16:02:02, Sourabh Jain wrote:
> On architectures like PowerPC the crash notes are available for all
> possible CPUs. So let's populate the elfcorehdr for all possible
> CPUs having crash notes to avoid updating elfcorehdr during in-kernel
> crash update on CPU hotplug events.
>
> The similar technique is used in kexec-tool for kexec_load case.
>
> Signed-off-by: Sourabh Jain
> ---
> kernel/crash_core.c | 9 ++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
This patch is not applying on ppc/next (53ab112a9508).
As far as I could see, crash_prepare_elf64_headers() is defined in the file
kernel/kexec_file.c and that's not recent, see babac4a84a88 (kexec_file,
x86: move re-factored code to generic side, 2018-04-13)
Am I missing something?
>
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index 910d377ea317e..19f987b3851e8 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -364,8 +364,8 @@ int crash_prepare_elf64_headers(struct kimage *image,
> struct crash_mem *mem,
> ehdr->e_ehsize = sizeof(Elf64_Ehdr);
> ehdr->e_phentsize = sizeof(Elf64_Phdr);
>
> - /* Prepare one phdr of type PT_NOTE for each present CPU */
> - for_each_present_cpu(cpu) {
> + /* Prepare one phdr of type PT_NOTE for possible CPU with crash note. */
> + for_each_possible_cpu(cpu) {
> #ifdef CONFIG_CRASH_HOTPLUG
> if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
> /* Skip the soon-to-be offlined cpu */
> @@ -373,8 +373,11 @@ int crash_prepare_elf64_headers(struct kimage *image,
> struct crash_mem *mem,
> continue;
> }
> #endif
> - phdr->p_type = PT_NOTE;
> notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
> + if (!notes_addr)
> + continue;
> +
> + phdr->p_type = PT_NOTE;
> phdr->p_offset = phdr->p_paddr = notes_addr;
> phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
> (ehdr->e_phnum)++;
[PATCH v7 4/8] crash: add phdr for possible CPUs in elfcorehdr
On architectures like PowerPC the crash notes are available for all
possible CPUs. So let's populate the elfcorehdr for all possible
CPUs having crash notes to avoid updating elfcorehdr during in-kernel
crash update on CPU hotplug events.
The similar technique is used in kexec-tool for kexec_load case.
Signed-off-by: Sourabh Jain
---
kernel/crash_core.c | 9 ++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 910d377ea317e..19f987b3851e8 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -364,8 +364,8 @@ int crash_prepare_elf64_headers(struct kimage *image,
struct crash_mem *mem,
ehdr->e_ehsize = sizeof(Elf64_Ehdr);
ehdr->e_phentsize = sizeof(Elf64_Phdr);
- /* Prepare one phdr of type PT_NOTE for each present CPU */
- for_each_present_cpu(cpu) {
+ /* Prepare one phdr of type PT_NOTE for possible CPU with crash note. */
+ for_each_possible_cpu(cpu) {
#ifdef CONFIG_CRASH_HOTPLUG
if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
/* Skip the soon-to-be offlined cpu */
@@ -373,8 +373,11 @@ int crash_prepare_elf64_headers(struct kimage *image,
struct crash_mem *mem,
continue;
}
#endif
- phdr->p_type = PT_NOTE;
notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
+ if (!notes_addr)
+ continue;
+
+ phdr->p_type = PT_NOTE;
phdr->p_offset = phdr->p_paddr = notes_addr;
phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
(ehdr->e_phnum)++;
--
2.39.0
