From: Guenter Roeck <linux@roeck-us.net> mainline inclusion from mainline-v6.12-rc1 commit a3344078101ceee46d14a93f7e3a3b91a55d215b category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/15533 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- SPLIT_PTE_PTLOCKS depends on "NR_CPUS >= 4". Unfortunately, that evaluates to true if there is no NR_CPUS configuration option. This results in CONFIG_SPLIT_PTE_PTLOCKS=y for mac_defconfig. This in turn causes the m68k "q800" and "virt" machines to crash in qemu if debugging options are enabled. Making CONFIG_SPLIT_PTE_PTLOCKS dependent on the existence of NR_CPUS does not work since a dependency on the existence of a numeric Kconfig entry always evaluates to false. Example: config HAVE_NO_NR_CPUS def_bool y depends on !NR_CPUS After adding this to a Kconfig file, "make defconfig" includes: $ grep NR_CPUS .config CONFIG_NR_CPUS=64 CONFIG_HAVE_NO_NR_CPUS=y Defining NR_CPUS for m68k does not help either since many architectures define NR_CPUS only for SMP configurations. Make SPLIT_PTE_PTLOCKS depend on SMP instead to solve the problem. Link: https://lkml.kernel.org/r/20240924154205.1491376-1-linux@roeck-us.net Fixes: 394290cba966 ("mm: turn USE_SPLIT_PTE_PTLOCKS / USE_SPLIT_PTE_PTLOCKS into Kconfig options") Signed-off-by: Guenter Roeck <linux@roeck-us.net> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Qi Xi <xiqi2@huawei.com> --- mm/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/Kconfig b/mm/Kconfig index 88b15c387efd..58432d1ebf76 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -619,6 +619,7 @@ config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE config SPLIT_PTE_PTLOCKS def_bool y depends on MMU + depends on SMP depends on NR_CPUS >= 4 depends on !ARM || CPU_CACHE_VIPT depends on !PARISC || PA20 -- 2.53.0