There are regression reports[1][2] that crashkernel region on x86_64 can't
be added into iomem tree sometime. This causes the later failure of kdump
loading.
This happened after commit 4a693ce65b18 ("kdump: defer the insertion of
crashkernel resources") was merged.
Even though, these reported issues are proved to be related to other
component, they are just exposed after above commmit applied, I still
would like to keep crashk_res and crashk_low_res being added into iomem
early as before because the early adding has been always there on x86_64
and working very well. For safety of kdump, Let's change it back.
Here, add a macro HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY to limit that
only ARCH defining the macro can have the early adding
crashk_res/_low_res into iomem. Then define
HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY on x86 to enable it.
Note: In reserve_crashkernel_low(), there's a remnant of crashk_low_res
hanlding which was mistakenly added back in commit 85fcde402db1 ("kexec:
split crashkernel reservation code out from crash_core.c").
[1]
[PATCH V2] x86/kexec: do not update E820 kexec table for setup_data
https://lore.kernel.org/all/[email protected]/T/#u
[2]
Question about Address Range Validation in Crash Kernel Allocation
https://lore.kernel.org/all/[email protected]/T/#u
Signed-off-by: Baoquan He <[email protected]>
---
arch/x86/include/asm/crash_reserve.h | 2 ++
kernel/crash_reserve.c | 7 +++++++
2 files changed, 9 insertions(+)
diff --git a/arch/x86/include/asm/crash_reserve.h b/arch/x86/include/asm/crash_reserve.h
index 152239f95541..4681a543eba3 100644
--- a/arch/x86/include/asm/crash_reserve.h
+++ b/arch/x86/include/asm/crash_reserve.h
@@ -39,4 +39,6 @@ static inline unsigned long crash_low_size_default(void)
#endif
}
+# define HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
+
#endif /* _X86_CRASH_RESERVE_H */
diff --git a/kernel/crash_reserve.c b/kernel/crash_reserve.c
index bbb6c3cb00e4..066668799f75 100644
--- a/kernel/crash_reserve.c
+++ b/kernel/crash_reserve.c
@@ -366,7 +366,9 @@ static int __init reserve_crashkernel_low(unsigned long long low_size)
crashk_low_res.start = low_base;
crashk_low_res.end = low_base + low_size - 1;
+#ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
insert_resource(&iomem_resource, &crashk_low_res);
+#endif
#endif
return 0;
}
@@ -448,8 +450,12 @@ void __init reserve_crashkernel_generic(char *cmdline,
crashk_res.start = crash_base;
crashk_res.end = crash_base + crash_size - 1;
+#ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
+ insert_resource(&iomem_resource, &crashk_res);
+#endif
}
+#ifndef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
static __init int insert_crashkernel_resources(void)
{
if (crashk_res.start < crashk_res.end)
@@ -462,3 +468,4 @@ static __init int insert_crashkernel_resources(void)
}
early_initcall(insert_crashkernel_resources);
#endif
+#endif
--
2.41.0
* Baoquan He <[email protected]> wrote:
> There are regression reports[1][2] that crashkernel region on x86_64 can't
> be added into iomem tree sometime. This causes the later failure of kdump
> loading.
>
> This happened after commit 4a693ce65b18 ("kdump: defer the insertion of
> crashkernel resources") was merged.
>
> Even though, these reported issues are proved to be related to other
> component, they are just exposed after above commmit applied, I still
> would like to keep crashk_res and crashk_low_res being added into iomem
> early as before because the early adding has been always there on x86_64
> and working very well. For safety of kdump, Let's change it back.
>
> Here, add a macro HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY to limit that
> only ARCH defining the macro can have the early adding
> crashk_res/_low_res into iomem. Then define
> HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY on x86 to enable it.
>
> Note: In reserve_crashkernel_low(), there's a remnant of crashk_low_res
> hanlding which was mistakenly added back in commit 85fcde402db1 ("kexec:
> split crashkernel reservation code out from crash_core.c").
>
> [1]
> [PATCH V2] x86/kexec: do not update E820 kexec table for setup_data
> https://lore.kernel.org/all/[email protected]/T/#u
>
> [2]
> Question about Address Range Validation in Crash Kernel Allocation
> https://lore.kernel.org/all/[email protected]/T/#u
>
> Signed-off-by: Baoquan He <[email protected]>
> ---
> arch/x86/include/asm/crash_reserve.h | 2 ++
> kernel/crash_reserve.c | 7 +++++++
> 2 files changed, 9 insertions(+)
>
> diff --git a/arch/x86/include/asm/crash_reserve.h b/arch/x86/include/asm/crash_reserve.h
> index 152239f95541..4681a543eba3 100644
> --- a/arch/x86/include/asm/crash_reserve.h
> +++ b/arch/x86/include/asm/crash_reserve.h
> @@ -39,4 +39,6 @@ static inline unsigned long crash_low_size_default(void)
> #endif
> }
>
> +# define HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
> +
Any reason for that stray space?
Thanks,
Ingo
On 03/24/24 at 05:06am, Ingo Molnar wrote:
>
> * Baoquan He <[email protected]> wrote:
>
.....snip
> > ---
> > arch/x86/include/asm/crash_reserve.h | 2 ++
> > kernel/crash_reserve.c | 7 +++++++
> > 2 files changed, 9 insertions(+)
> >
> > diff --git a/arch/x86/include/asm/crash_reserve.h b/arch/x86/include/asm/crash_reserve.h
> > index 152239f95541..4681a543eba3 100644
> > --- a/arch/x86/include/asm/crash_reserve.h
> > +++ b/arch/x86/include/asm/crash_reserve.h
> > @@ -39,4 +39,6 @@ static inline unsigned long crash_low_size_default(void)
> > #endif
> > }
> >
> > +# define HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
> > +
>
> Any reason for that stray space?
No clear reason. I saw stray space was added for macro definning when my
below patch was merged, not sure if this is preferred. And there are
a lot of "# define " when searching with 'git grep "# define " arch/x86/include/'.
commit 85fcde402db1 ("kexec: split crashkernel reservation code out from crash_core.c")
* Baoquan He <[email protected]> wrote:
> On 03/24/24 at 05:06am, Ingo Molnar wrote:
> >
> > * Baoquan He <[email protected]> wrote:
> >
> ......snip
> > > ---
> > > arch/x86/include/asm/crash_reserve.h | 2 ++
> > > kernel/crash_reserve.c | 7 +++++++
> > > 2 files changed, 9 insertions(+)
> > >
> > > diff --git a/arch/x86/include/asm/crash_reserve.h b/arch/x86/include/asm/crash_reserve.h
> > > index 152239f95541..4681a543eba3 100644
> > > --- a/arch/x86/include/asm/crash_reserve.h
> > > +++ b/arch/x86/include/asm/crash_reserve.h
> > > @@ -39,4 +39,6 @@ static inline unsigned long crash_low_size_default(void)
> > > #endif
> > > }
> > >
> > > +# define HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
> > > +
> >
> > Any reason for that stray space?
>
> No clear reason. I saw stray space was added for macro definning when my
> below patch was merged, not sure if this is preferred.
No, it's not preferred - and I don't see any stray spaces added in the
code added by:
> commit 85fcde402db1 ("kexec: split crashkernel reservation code out from crash_core.c")
Anyway, please just remove it.
> And there are a lot of "# define " when searching with 'git grep "#
> define " arch/x86/include/'.
The overwhelming majority of those are not standalone defines like
yours, but nested/conditional defines where the space is justified:
#ifdef CONFIG_X86_32
# define MAX_IO_APICS 64
# define MAX_LOCAL_APIC 256
#else
# define MAX_IO_APICS 128
# define MAX_LOCAL_APIC 32768
#endif
Thanks,
Ingo
There are regression reports[1][2] that crashkernel region on x86_64 can't
be added into iomem tree sometime. This causes the later failure of kdump
loading.
This happened after commit 4a693ce65b18 ("kdump: defer the insertion of
crashkernel resources") was merged.
Even though, these reported issues are proved to be related to other
component, they are just exposed after above commmit applied, I still
would like to keep crashk_res and crashk_low_res being added into iomem
early as before because the early adding has been always there on x86_64
and working very well. For safety of kdump, Let's change it back.
Here, add a macro HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY to limit that
only ARCH defining the macro can have the early adding
crashk_res/_low_res into iomem. Then define
HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY on x86 to enable it.
Note: In reserve_crashkernel_low(), there's a remnant of crashk_low_res
hanlding which was mistakenly added back in commit 85fcde402db1 ("kexec:
split crashkernel reservation code out from crash_core.c").
[1]
[PATCH V2] x86/kexec: do not update E820 kexec table for setup_data
https://lore.kernel.org/all/[email protected]/T/#u
[2]
Question about Address Range Validation in Crash Kernel Allocation
https://lore.kernel.org/all/[email protected]/T/#u
Signed-off-by: Baoquan He <[email protected]>
---
v1->v2:
- Remove the stray space before 'define' when defining
HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY in asm/crash_reserve.h of x86.
This is not suggested for standalone macro defines. Thanks to Ingo.
arch/x86/include/asm/crash_reserve.h | 2 ++
kernel/crash_reserve.c | 7 +++++++
2 files changed, 9 insertions(+)
diff --git a/arch/x86/include/asm/crash_reserve.h b/arch/x86/include/asm/crash_reserve.h
index 152239f95541..7835b2cdff04 100644
--- a/arch/x86/include/asm/crash_reserve.h
+++ b/arch/x86/include/asm/crash_reserve.h
@@ -39,4 +39,6 @@ static inline unsigned long crash_low_size_default(void)
#endif
}
+#define HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
+
#endif /* _X86_CRASH_RESERVE_H */
diff --git a/kernel/crash_reserve.c b/kernel/crash_reserve.c
index bbb6c3cb00e4..066668799f75 100644
--- a/kernel/crash_reserve.c
+++ b/kernel/crash_reserve.c
@@ -366,7 +366,9 @@ static int __init reserve_crashkernel_low(unsigned long long low_size)
crashk_low_res.start = low_base;
crashk_low_res.end = low_base + low_size - 1;
+#ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
insert_resource(&iomem_resource, &crashk_low_res);
+#endif
#endif
return 0;
}
@@ -448,8 +450,12 @@ void __init reserve_crashkernel_generic(char *cmdline,
crashk_res.start = crash_base;
crashk_res.end = crash_base + crash_size - 1;
+#ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
+ insert_resource(&iomem_resource, &crashk_res);
+#endif
}
+#ifndef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
static __init int insert_crashkernel_resources(void)
{
if (crashk_res.start < crashk_res.end)
@@ -462,3 +468,4 @@ static __init int insert_crashkernel_resources(void)
}
early_initcall(insert_crashkernel_resources);
#endif
+#endif
--
2.41.0
On 03/24/24 at 11:27am, Ingo Molnar wrote:
>
> * Baoquan He <[email protected]> wrote:
>
> > On 03/24/24 at 05:06am, Ingo Molnar wrote:
> > >
> > > * Baoquan He <[email protected]> wrote:
> > >
> > ......snip
> > > > ---
> > > > arch/x86/include/asm/crash_reserve.h | 2 ++
> > > > kernel/crash_reserve.c | 7 +++++++
> > > > 2 files changed, 9 insertions(+)
> > > >
> > > > diff --git a/arch/x86/include/asm/crash_reserve.h b/arch/x86/include/asm/crash_reserve.h
> > > > index 152239f95541..4681a543eba3 100644
> > > > --- a/arch/x86/include/asm/crash_reserve.h
> > > > +++ b/arch/x86/include/asm/crash_reserve.h
> > > > @@ -39,4 +39,6 @@ static inline unsigned long crash_low_size_default(void)
> > > > #endif
> > > > }
> > > >
> > > > +# define HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
> > > > +
> > >
> > > Any reason for that stray space?
> >
> > No clear reason. I saw stray space was added for macro definning when my
> > below patch was merged, not sure if this is preferred.
>
> No, it's not preferred - and I don't see any stray spaces added in the
> code added by:
>
> > commit 85fcde402db1 ("kexec: split crashkernel reservation code out from crash_core.c")
Ah, the stray spaces are added in below macros defining, I thought they
are all the same. I didn't know nested/conditional defines and
standalone defines are different. Thanks for careful checking and telling.
arch/x86/include/asm/crash_reserve.h:
#ifdef CONFIG_X86_32
# define CRASH_ADDR_LOW_MAX SZ_512M
# define CRASH_ADDR_HIGH_MAX SZ_512M
#else
# define CRASH_ADDR_LOW_MAX SZ_4G
# define CRASH_ADDR_HIGH_MAX SZ_64T
#endif
>
> Anyway, please just remove it.
Sure, will update and v2.
>
> > And there are a lot of "# define " when searching with 'git grep "#
> > define " arch/x86/include/'.
>
> The overwhelming majority of those are not standalone defines like
> yours, but nested/conditional defines where the space is justified:
>
> #ifdef CONFIG_X86_32
> # define MAX_IO_APICS 64
> # define MAX_LOCAL_APIC 256
> #else
> # define MAX_IO_APICS 128
> # define MAX_LOCAL_APIC 32768
> #endif
>
> Thanks,
>
> Ingo
>
On Mon, 25 Mar 2024 09:50:50 +0800 Baoquan He <[email protected]> wrote:
> There are regression reports[1][2] that crashkernel region on x86_64 can't
> be added into iomem tree sometime. This causes the later failure of kdump
> loading.
So I think a cc:stable is needed.
> This happened after commit 4a693ce65b18 ("kdump: defer the insertion of
> crashkernel resources") was merged.
>
> Even though, these reported issues are proved to be related to other
> component, they are just exposed after above commmit applied, I still
> would like to keep crashk_res and crashk_low_res being added into iomem
> early as before because the early adding has been always there on x86_64
> and working very well. For safety of kdump, Let's change it back.
I'll use 4a693ce65b18 as the Fixes: target, since there is no
"Exposed-by-non-buggy-patch:" tag. To tell the -stable tree
maintainers how far back in history this should be backported.
On 03/25/24 at 01:29pm, Andrew Morton wrote:
> On Mon, 25 Mar 2024 09:50:50 +0800 Baoquan He <[email protected]> wrote:
>
> > There are regression reports[1][2] that crashkernel region on x86_64 can't
> > be added into iomem tree sometime. This causes the later failure of kdump
> > loading.
>
> So I think a cc:stable is needed.
Yeah, I forgot this.
>
> > This happened after commit 4a693ce65b18 ("kdump: defer the insertion of
> > crashkernel resources") was merged.
> >
> > Even though, these reported issues are proved to be related to other
> > component, they are just exposed after above commmit applied, I still
> > would like to keep crashk_res and crashk_low_res being added into iomem
> > early as before because the early adding has been always there on x86_64
> > and working very well. For safety of kdump, Let's change it back.
>
> I'll use 4a693ce65b18 as the Fixes: target, since there is no
> "Exposed-by-non-buggy-patch:" tag. To tell the -stable tree
> maintainers how far back in history this should be backported.
Thanks a lot.