Aksal/nuttx
3
1
Fork 1
mirror of https://github.com/apache/nuttx.git synced 2026-08-07 13:37:18 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 2

arch/x86_64: fix page table levels in pgalloc

Browse source 
Two level errors corrupted kernel memory when a user process extended
its heap with sbrk:

- PGT_LAST was X86_MMU_PT_LEVELS (4), but valid levels are 0-3, so the
  final level entry was written with an out-of-range index.

- x86_64_get_pgtable indexed the PD (level 2) with level 3, installing
  newly allocated page tables into the wrong PD slot.

Signed-off-by: raiden00pl <raiden00@railab.me>
Assisted-by: Claude Code
This commit is contained in:
raiden00pl 2026-08-04 21:37:03 +02:00 • committed by Matteo Golin
parent c25a5021b4
commit 804249a0b2
1 changed files with 2 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

4
arch/x86_64/src/common/x86_64_pgalloc.c
View file

@ -50,7 +50,7 @@
/* Last PGT level */
#define PGT_LAST (X86_MMU_PT_LEVELS)
#define PGT_LAST (X86_MMU_PT_LEVELS - 1)
/****************************************************************************
* Private Functions
@ -82,7 +82,7 @@ uintptr_t x86_64_get_pgtable(arch_addrenv_t *addrenv, uintptr_t vaddr)
/* Get the current level MAX_LEVELS-1 entry corresponding to this vaddr */
ptlevel = ARCH_SPGTS;
ptlevel = ARCH_SPGTS - 1;
ptprev = x86_64_pgvaddr(addrenv->spgtables[ARCH_SPGTS - 1]);
if (!ptprev)
{