On 24.09.24 17:42, Guenter Roeck wrote:
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.
Fixes: 394290cba966 ("mm: turn USE_SPLIT_PTE_PTLOCKS / USE_SPLIT_PTE_PTLOCKS into Kconfig options")
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
--
Cheers,
David / dhildenb
