Commit 50dbe788 authored by Yongqiang Liu's avatar Yongqiang Liu Committed by Jinjiang Tu
Browse files

ARM: 9359/1: flush: check if the folio is reserved for no-mapping addresses 

mainline inclusion
from mainline-v6.9-rc1
commit 0c66c6f4e21cb22220cbd8821c5c73fc157d20dc
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9L5E2
CVE: CVE-2024-26947

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0c66c6f4e21cb22220cbd8821c5c73fc157d20dc

--------------------------------

Since commit a4d5613c ("arm: extend pfn_valid to take into account
freed memory map alignment") changes the semantics of pfn_valid() to check
presence of the memory map for a PFN. A valid page for an address which
is reserved but not mapped by the kernel[1], the system crashed during
some uio test with the following memory layout:

 node   0: [mem 0x00000000c0a00000-0x00000000cc8fffff]
 node   0: [mem 0x00000000d0000000-0x00000000da1fffff]
 the uio layout is：0xc0900000, 0x100000

the crash backtrace like:

  Unable to handle kernel paging request at virtual address bff00000
  [...]
  CPU: 1 PID: 465 Comm: startapp.bin Tainted: G           O      5.10.0 #1
  Hardware name: Generic DT based system
  PC is at b15_flush_kern_dcache_area+0x24/0x3c
  LR is at __sync_icache_dcache+0x6c/0x98
  [...]
   (b15_flush_kern_dcache_area) from (__sync_icache_dcache+0x6c/0x98)
   (__sync_icache_dcache) from (set_pte_at+0x28/0x54)
   (set_pte_at) from (remap_pfn_range+0x1a0/0x274)
   (remap_pfn_range) from (uio_mmap+0x184/0x1b8 [uio])
   (uio_mmap [uio]) from (__mmap_region+0x264/0x5f4)
   (__mmap_region) from (__do_mmap_mm+0x3ec/0x440)
   (__do_mmap_mm) from (do_mmap+0x50/0x58)
   (do_mmap) from (vm_mmap_pgoff+0xfc/0x188)
   (vm_mmap_pgoff) from (ksys_mmap_pgoff+0xac/0xc4)
   (ksys_mmap_pgoff) from (ret_fast_syscall+0x0/0x5c)
  Code: e0801001 e2423001 e1c00003 f57ff04f (ee070f3e)
  ---[ end trace 09cf0734c3805d52 ]---
  Kernel panic - not syncing: Fatal exception

So check if PG_reserved was set to solve this issue.

[1]: https://lore.kernel.org/lkml/Zbtdue57RO0QScJM@linux.ibm.com/



Fixes: a4d5613c ("arm: extend pfn_valid to take into account freed memory map alignment")
Suggested-by: default avatarMike Rapoport <rppt@linux.ibm.com>
Signed-off-by: default avatarYongqiang Liu <liuyongqiang13@huawei.com>
Signed-off-by: default avatarRussell King (Oracle) <rmk+kernel@armlinux.org.uk>

Conflicts:
	arch/arm/mm/flush.c
[Conflicts due to folio api.]
Signed-off-by: default avatarJinjiang Tu <tujinjiang@huawei.com>
parent 78a2fd36

arch/arm/mm/flush.c

+3 −0
Original line number Diff line number Diff line
@@ -280,6 +280,9 @@ void __sync_icache_dcache(pte_t pteval) 
		return;



	page = pfn_to_page(pfn);

	if (PageReserved(page))

		return;



	if (cache_is_vipt_aliasing())

		mapping = page_mapping_file(page);

	else