Mike Rapoport (IBM) b5046b2532 x86/mm: Drop the 4 MB restriction on minimal NUMA node memory size ... [ Upstream commit a1e2b8b368 ] Qi Zheng reported crashes in a production environment and provided a simplified example as a reproducer: | For example, if we use Qemu to start a two NUMA node kernel, | one of the nodes has 2M memory (less than NODE_MIN_SIZE), | and the other node has 2G, then we will encounter the | following panic: | | BUG: kernel NULL pointer dereference, address: 0000000000000000 | <...> | RIP: 0010:_raw_spin_lock_irqsave+0x22/0x40 | <...> | Call Trace: | <TASK> | deactivate_slab() | bootstrap() | kmem_cache_init() | start_kernel() | secondary_startup_64_no_verify() The crashes happen because of inconsistency between the nodemask that has nodes with less than 4MB as memoryless, and the actual memory fed into the core mm. The commit: 9391a3f9c7 ("[PATCH] x86_64: Clear more state when ignoring empty node in SRAT parsing") ... that introduced minimal size of a NUMA node does not explain why a node size cannot be less than 4MB and what boot failures this restriction might fix. Fixes have been submitted to the core MM code to tighten up the memory topologies it accepts and to not crash on weird input: mm: page_alloc: skip memoryless nodes entirely mm: memory_hotplug: drop memoryless node from fallback lists Andrew has accepted them into the -mm tree, but there are no stable SHA1's yet. This patch drops the limitation for minimal node size on x86: - which works around the crash without the fixes to the core MM. - makes x86 topologies less weird, - removes an arbitrary and undocumented limitation on NUMA topologies. [ mingo: Improved changelog clarity. ] Reported-by: Qi Zheng <zhengqi.arch@bytedance.com> Tested-by: Mario Casquero <mcasquer@redhat.com> Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Rik van Riel <riel@surriel.com> Link: https://lore.kernel.org/r/ZS+2qqjEO5/867br@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>		2023-11-28 17:06:55 +00:00
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alpha	alpha: remove __init annotation from exported page_is_ram()	2023-08-16 18:27:31 +02:00
arc	ARC: atomics: Add compiler barrier to atomic operations...	2023-09-19 12:28:04 +02:00
arm	ARM: 9321/1: memset: cast the constant byte to unsigned char	2023-11-20 11:52:06 +01:00
arm64	arm64: tegra: Use correct interrupts for Tegra234 TKE	2023-11-20 11:52:03 +01:00
csky	…
hexagon	…
ia64	…
loongarch	LoongArch: Replace kmap_atomic() with kmap_local_page() in copy_user_highpage()	2023-11-08 14:11:01 +01:00
m68k	m68k: Fix invalid .section syntax	2023-09-13 09:42:21 +02:00
microblaze	…
mips	MIPS: Alchemy: only build mmc support helpers if au1xmmc is enabled	2023-10-06 14:56:45 +02:00
nios2	…
openrisc	…
parisc	parisc: Restore __ldcw_align for PA-RISC 2.0 processors	2023-10-10 22:00:45 +02:00
powerpc	powerpc/pseries: fix potential memory leak in init_cpu_associativity()	2023-11-20 11:52:12 +01:00
riscv	RISC-V: Don't fail in riscv_of_parent_hartid() for disabled HARTs	2023-11-20 11:52:17 +01:00
s390	s390/pci: fix iommu bitmap allocation	2023-10-25 12:03:15 +02:00
sh	sh: bios: Revive earlyprintk support	2023-11-20 11:52:07 +01:00
sparc	sparc32: fix a braino in fault handling in csum_and_copy_..._user()	2023-11-02 09:35:32 +01:00
um	um: Fix hostaudio build errors	2023-09-13 09:42:58 +02:00
x86	x86/mm: Drop the 4 MB restriction on minimal NUMA node memory size	2023-11-28 17:06:55 +00:00
xtensa	xtensa: boot/lib: fix function prototypes	2023-10-06 14:56:49 +02:00
.gitignore	…
Kconfig	…