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* [PATCH] arch: arm64: fix KERNEL_SEGMENT_COUNT error
@ 2026-04-29  6:17 zhaoyang.huang
  2026-04-29  8:03 ` Zhaoyang Huang
  2026-04-29  9:27 ` Ard Biesheuvel
  0 siblings, 2 replies; 6+ messages in thread
From: zhaoyang.huang @ 2026-04-29  6:17 UTC (permalink / raw)
  To: Catalin Marinas, Will Deacon, Ard Biesheuvel, linux-arm-kernel,
	linux-kernel, Zhaoyang Huang, steve.kang

From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>

During debug of a kernel panic, we find that the pte_t of the final
part of [data, end] segment got overflow to the next page of
init_pg_end[1] which is the gap page before early_init_stack[2].
This should be introduced by the KERNEL_SEGMENT_COUNT's value is 5
which should be 6 as map_segment are called 6 times for the segments
of (text, stext, rodata, inittext, initdata, data+bss)

[1]
crash_arm64_v9.0.1> vtop ffffffed00601000
VIRTUAL           PHYSICAL
ffffffed00601000  83401000

PAGE DIRECTORY: ffffffecffd62000
   PGD: ffffffecffd62da0 => 10000000833fb003
   PMD: ffffff80033fb018 => 10000000833fe003
   PTE: ffffff80033fe008 => 68000083401f03
  PAGE: 83401000

     PTE        PHYSICAL  FLAGS
68000083401f03  83401000  (VALID|SHARED|AF|NG|PXN|UXN)

      PAGE       PHYSICAL      MAPPING       INDEX CNT FLAGS
fffffffec00d0040 83401000                0        0  1 4000 reserved

[2]
ffffffed002c8000 (r) __pi__data
ffffffed0054e000 (d) __pi___bss_start
ffffffed005f5000 (b) __pi_init_pg_dir
ffffffed005fe000 (b) __pi_init_pg_end
ffffffed005ff000 (B) early_init_stack
ffffffed00608000 (b) __pi__end

Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
---
 arch/arm64/include/asm/kernel-pgtable.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h
index 74a4f738c5f5..14dd1c52552a 100644
--- a/arch/arm64/include/asm/kernel-pgtable.h
+++ b/arch/arm64/include/asm/kernel-pgtable.h
@@ -64,8 +64,8 @@
 #define INIT_IDMAP_FDT_PAGES	(EARLY_PAGES(INIT_IDMAP_PGTABLE_LEVELS, 0UL, UL(MAX_FDT_SIZE), 1) - 1)
 #define INIT_IDMAP_FDT_SIZE	((INIT_IDMAP_FDT_PAGES + EARLY_IDMAP_EXTRA_FDT_PAGES) * PAGE_SIZE)
 
-/* The number of segments in the kernel image (text, rodata, inittext, initdata, data+bss) */
-#define KERNEL_SEGMENT_COUNT	5
+/* The number of segments in the kernel image (text, stext, rodata, inittext, initdata, data+bss) */
+#define KERNEL_SEGMENT_COUNT	6
 
 #if SWAPPER_BLOCK_SIZE > SEGMENT_ALIGN
 #define EARLY_SEGMENT_EXTRA_PAGES (KERNEL_SEGMENT_COUNT + 1)
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2026-04-30  7:59 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2026-04-29  6:17 [PATCH] arch: arm64: fix KERNEL_SEGMENT_COUNT error zhaoyang.huang
2026-04-29  8:03 ` Zhaoyang Huang
2026-04-29  9:27 ` Ard Biesheuvel
2026-04-30  1:29   ` Zhaoyang Huang
2026-04-30  1:56     ` Zhaoyang Huang
2026-04-30  7:59       ` Ard Biesheuvel

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