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| author | Ard Biesheuvel <ardb@kernel.org> | 2026-06-04 17:11:57 +0200 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2026-06-05 11:44:10 +0100 |
| commit | 53205d56212cbff880a77497e25a0e44036d490a (patch) | |
| tree | ea6b994a2079843d770f509dcd79800c4b2bd24b | |
| parent | 2986a625740599fe6e7635b0586fed2a95bcd1f7 (diff) | |
| download | linux-53205d56212cbff880a77497e25a0e44036d490a.tar.gz linux-53205d56212cbff880a77497e25a0e44036d490a.zip | |
arm64: mm: Defer remap of linear alias of data/bss
Marking the linear alias of data/bss invalid involves calling
set_memory_valid(), which calls split_kernel_leaf_mapping() under the
hood.
On BBML2_NOABORT capable systems, this may result in the need to
allocate page tables at a time when the generic memory allocation APIs
are not yet available, resulting in a splat like
WARNING: arch/arm64/mm/mmu.c:821 at split_kernel_leaf_mapping+0x15c/0x170, CPU#0: swapper/0
Modules linked in:
CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 7.1.0-rc6 #1 PREEMPT(undef)
pstate: a04000c9 (NzCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : split_kernel_leaf_mapping+0x15c/0x170
lr : update_range_prot+0x40/0x128
sp : ffffc99ad3863c80
...
Call trace:
split_kernel_leaf_mapping+0x15c/0x170 (P)
update_range_prot+0x40/0x128
set_memory_valid+0x94/0xe0
mark_linear_data_alias_valid+0x54/0x68
map_mem+0x1fc/0x240
paging_init+0x48/0x210
setup_arch+0x274/0x338
start_kernel+0x98/0x538
__primary_switched+0x88/0x98
as reported by CKI automated testing.
So defer the boot-time call to mark_linear_data_alias_valid() to a later
time when page allocations can be made normally.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
| -rw-r--r-- | arch/arm64/mm/mmu.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index d68e691c093a..3134f1c1097c 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1095,6 +1095,9 @@ void __init mark_linear_text_alias_ro(void) (unsigned long)__init_begin - (unsigned long)_text, PAGE_KERNEL_RO); + /* Map the kernel data/bss as invalid in the linear map */ + mark_linear_data_alias_valid(false); + /* * Register a PM notifier to remap the linear alias of data/bss as * valid read-only before hibernation. This is needed because the @@ -1237,9 +1240,6 @@ static void __init map_mem(void) __map_memblock(start, end, pgprot_tagged(PAGE_KERNEL), flags); } - - /* Map the kernel data/bss as invalid in the linear map */ - mark_linear_data_alias_valid(false); } void mark_rodata_ro(void) |