The patch titled Subject: crash: use macro to add crashk_res into iomem early for specific arch has been added to the -mm mm-hotfixes-unstable branch. Its filename is crash-use-macro-to-add-crashk_res-into-iomem-early-for-specific-arch.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Baoquan He bhe@redhat.com Subject: crash: use macro to add crashk_res into iomem early for specific arch Date: Mon, 25 Mar 2024 09:50:50 +0800

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 handling 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/Zfv8iCL6CT2JqLIC@darkstar.users.ipa.redhat.com/T...

[2] Question about Address Range Validation in Crash Kernel Allocation https://lore.kernel.org/all/4eeac1f733584855965a2ea62fa4da58@huawei.com/T/#u

Link: https://lkml.kernel.org/r/ZgDYemRQ2jxjLkq+@MiWiFi-R3L-srv Fixes: 4a693ce65b18 ("kdump: defer the insertion of crashkernel resources") Signed-off-by: Baoquan He bhe@redhat.com Cc: Dave Young dyoung@redhat.com Cc: Huacai Chen chenhuacai@loongson.cn Cc: Ingo Molnar mingo@kernel.org Cc: Jiri Bohac jbohac@suse.cz Cc: Li Huafei lihuafei1@huawei.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

arch/x86/include/asm/crash_reserve.h | 2 ++ kernel/crash_reserve.c | 7 +++++++ 2 files changed, 9 insertions(+)

--- a/arch/x86/include/asm/crash_reserve.h~crash-use-macro-to-add-crashk_res-into-iomem-early-for-specific-arch +++ a/arch/x86/include/asm/crash_reserve.h @@ -39,4 +39,6 @@ static inline unsigned long crash_low_si #endif }

+#define HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY + #endif /* _X86_CRASH_RESERVE_H */ --- a/kernel/crash_reserve.c~crash-use-macro-to-add-crashk_res-into-iomem-early-for-specific-arch +++ a/kernel/crash_reserve.c @@ -366,8 +366,10 @@ static int __init reserve_crashkernel_lo

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 @@ retry:

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_res } early_initcall(insert_crashkernel_resources); #endif +#endif _

Patches currently in -mm which might be from bhe@redhat.com are

crash-use-macro-to-add-crashk_res-into-iomem-early-for-specific-arch.patch mm-vmallocc-optimize-to-reduce-arguments-of-alloc_vmap_area.patch x86-remove-unneeded-memblock_find_dma_reserve.patch mm-mm_initc-remove-the-useless-dma_reserve.patch mm-mm_initc-add-new-function-calc_nr_all_pages.patch mm-mm_initc-remove-meaningless-calculation-of-zone-managed_pages-in-free_area_init_core.patch mm-mm_initc-remove-unneeded-calc_memmap_size.patch mm-mm_initc-remove-arch_reserved_kernel_pages.patch