"value":"In the Linux kernel, the following vulnerability has been resolved:\n\narm64/mm: fix incorrect file_map_count for invalid pmd\n\nThe page table check trigger BUG_ON() unexpectedly when split hugepage:\n\n ------------[ cut here ]------------\n kernel BUG at mm/page_table_check.c:119!\n Internal error: Oops - BUG: 00000000f2000800 [#1] SMP\n Dumping ftrace buffer:\n (ftrace buffer empty)\n Modules linked in:\n CPU: 7 PID: 210 Comm: transhuge-stres Not tainted 6.1.0-rc3+ #748\n Hardware name: linux,dummy-virt (DT)\n pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)\n pc : page_table_check_set.isra.0+0x398/0x468\n lr : page_table_check_set.isra.0+0x1c0/0x468\n[...]\n Call trace:\n page_table_check_set.isra.0+0x398/0x468\n __page_table_check_pte_set+0x160/0x1c0\n __split_huge_pmd_locked+0x900/0x1648\n __split_huge_pmd+0x28c/0x3b8\n unmap_page_range+0x428/0x858\n unmap_single_vma+0xf4/0x1c8\n zap_page_range+0x2b0/0x410\n madvise_vma_behavior+0xc44/0xe78\n do_madvise+0x280/0x698\n __arm64_sys_madvise+0x90/0xe8\n invoke_syscall.constprop.0+0xdc/0x1d8\n do_el0_svc+0xf4/0x3f8\n el0_svc+0x58/0x120\n el0t_64_sync_handler+0xb8/0xc0\n el0t_64_sync+0x19c/0x1a0\n[...]\n\nOn arm64, pmd_leaf() will return true even if the pmd is invalid due to\npmd_present_invalid() check. So in pmdp_invalidate() the file_map_count\nwill not only decrease once but also increase once. Then in set_pte_at(),\nthe file_map_count increase again, and so trigger BUG_ON() unexpectedly.\n\nAdd !pmd_present_invalid() check in pmd_user_accessible_page() to fix the\nproblem."
"value":"En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: arm64/mm: corrige file_map_count incorrecto para pmd no v\u00e1lido. La verificaci\u00f3n de la tabla de p\u00e1ginas activa BUG_ON() inesperadamente cuando se divide una p\u00e1gina enorme: ------------[ cortar aqu\u00ed ]------------ \u00a1ERROR del kernel en mm/page_table_check.c:119! Error interno: Ups - ERROR: 00000000f2000800 [#1] SMP Dumping ftrace buffer: (ftrace buffer vac\u00edo) M\u00f3dulos vinculados en: CPU: 7 PID: 210 Comm: transhuge-stres No contaminado 6.1.0-rc3+ #748 Nombre de hardware: linux ,dummy-virt (DT) pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc: page_table_check_set.isra.0+0x398/0x468 lr: page_table_check_set.isra.0+0x1c0/0x468 [...] Rastreo de llamadas: page_table_check_set.isra.0+0x398/0x468 __page_table_check_pte_set+0x160/0x1c0 __split_huge_pmd_locked+0x900/0x1648 __split_huge_pmd+0x28c/0x3b8 unmap_page_range+0x428/0x858 single_vma+0xf4/0x1c8 zap_page_range+0x2b0/0x410 madvise_vma_behavior+0xc44 /0xe78 do_madvise+0x280/0x698 __arm64_sys_madvise+0x90/0xe8 invoke_syscall.constprop.0+0xdc/0x1d8 do_el0_svc+0xf4/0x3f8 el0_svc+0x58/0x120 el0t_64_sync_handler+0x b8/0xc0 el0t_64_sync+0x19c/0x1a0 [...] En arm64, pmd_leaf () devolver\u00e1 verdadero incluso si el pmd no es v\u00e1lido debido a la verificaci\u00f3n pmd_present_invalid(). Entonces, en pmdp_invalidate() file_map_count no solo disminuir\u00e1 una vez sino que tambi\u00e9n aumentar\u00e1 una vez. Luego, en set_pte_at(), file_map_count aumenta nuevamente y, por lo tanto, activa BUG_ON() inesperadamente. Agregue !pmd_present_invalid() check in pmd_user_accessible_page() para solucionar el problema."