android_kernel_motorola_sm6375/arch/powerpc
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Christophe Leroy 97de585205 powerpc/code-patching: Fix KASAN hit by not flagging text patching area as VM_ALLOC
[ Upstream commit d262a192d38e527faa5984629aabda2e0d1c4f54 ]

Erhard reported the following KASAN hit while booting his PowerMac G4
with a KASAN-enabled kernel 6.13-rc6:

  BUG: KASAN: vmalloc-out-of-bounds in copy_to_kernel_nofault+0xd8/0x1c8
  Write of size 8 at addr f1000000 by task chronyd/1293

  CPU: 0 UID: 123 PID: 1293 Comm: chronyd Tainted: G        W          6.13.0-rc6-PMacG4 #2
  Tainted: [W]=WARN
  Hardware name: PowerMac3,6 7455 0x80010303 PowerMac
  Call Trace:
  [c2437590] [c1631a84] dump_stack_lvl+0x70/0x8c (unreliable)
  [c24375b0] [c0504998] print_report+0xdc/0x504
  [c2437610] [c050475c] kasan_report+0xf8/0x108
  [c2437690] [c0505a3c] kasan_check_range+0x24/0x18c
  [c24376a0] [c03fb5e4] copy_to_kernel_nofault+0xd8/0x1c8
  [c24376c0] [c004c014] patch_instructions+0x15c/0x16c
  [c2437710] [c00731a8] bpf_arch_text_copy+0x60/0x7c
  [c2437730] [c0281168] bpf_jit_binary_pack_finalize+0x50/0xac
  [c2437750] [c0073cf4] bpf_int_jit_compile+0xb30/0xdec
  [c2437880] [c0280394] bpf_prog_select_runtime+0x15c/0x478
  [c24378d0] [c1263428] bpf_prepare_filter+0xbf8/0xc14
  [c2437990] [c12677ec] bpf_prog_create_from_user+0x258/0x2b4
  [c24379d0] [c027111c] do_seccomp+0x3dc/0x1890
  [c2437ac0] [c001d8e0] system_call_exception+0x2dc/0x420
  [c2437f30] [c00281ac] ret_from_syscall+0x0/0x2c
  --- interrupt: c00 at 0x5a1274
  NIP:  005a1274 LR: 006a3b3c CTR: 005296c8
  REGS: c2437f40 TRAP: 0c00   Tainted: G        W           (6.13.0-rc6-PMacG4)
  MSR:  0200f932 <VEC,EE,PR,FP,ME,IR,DR,RI>  CR: 24004422  XER: 00000000

  GPR00: 00000166 af8f3fa0 a7ee3540 00000001 00000000 013b6500 005a5858 0200f932
  GPR08: 00000000 00001fe9 013d5fc8 005296c8 2822244c 00b2fcd8 00000000 af8f4b57
  GPR16: 00000000 00000001 00000000 00000000 00000000 00000001 00000000 00000002
  GPR24: 00afdbb0 00000000 00000000 00000000 006e0004 013ce060 006e7c1c 00000001
  NIP [005a1274] 0x5a1274
  LR [006a3b3c] 0x6a3b3c
  --- interrupt: c00

  The buggy address belongs to the virtual mapping at
   [f1000000, f1002000) created by:
   text_area_cpu_up+0x20/0x190

  The buggy address belongs to the physical page:
  page: refcount:1 mapcount:0 mapping:00000000 index:0x0 pfn:0x76e30
  flags: 0x80000000(zone=2)
  raw: 80000000 00000000 00000122 00000000 00000000 00000000 ffffffff 00000001
  raw: 00000000
  page dumped because: kasan: bad access detected

  Memory state around the buggy address:
   f0ffff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
   f0ffff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  >f1000000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
             ^
   f1000080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
   f1000100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
  ==================================================================

f8 corresponds to KASAN_VMALLOC_INVALID which means the area is not
initialised hence not supposed to be used yet.

Powerpc text patching infrastructure allocates a virtual memory area
using get_vm_area() and flags it as VM_ALLOC. But that flag is meant
to be used for vmalloc() and vmalloc() allocated memory is not
supposed to be used before a call to __vmalloc_node_range() which is
never called for that area.

That went undetected until commit e4137f08816b ("mm, kasan, kmsan:
instrument copy_from/to_kernel_nofault")

The area allocated by text_area_cpu_up() is not vmalloc memory, it is
mapped directly on demand when needed by map_kernel_page(). There is
no VM flag corresponding to such usage, so just pass no flag. That way
the area will be unpoisonned and usable immediately.

Reported-by: Erhard Furtner <erhard_f@mailbox.org>
Closes: https://lore.kernel.org/all/20250112135832.57c92322@yea/
Fixes: 37bc3e5fd7 ("powerpc/lib/code-patching: Use alternate map for patch_instruction()")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/06621423da339b374f48c0886e3a5db18e896be8.1739342693.git.christophe.leroy@csgroup.eu
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-13 12:43:22 +01:00
..
boot powerpc/boot: Only free if realloc() succeeds 2024-09-04 13:14:56 +02:00
configs Remove DECnet support from kernel 2023-06-21 15:44:10 +02:00
crypto
include powerpc/64s: Rewrite __real_pte() and __rpte_to_hidx() as static inline 2025-03-13 12:43:22 +01:00
kernel powerpc/prom_init: Fixup missing powermac #size-cells 2024-12-14 19:44:54 +01:00
kvm powerpc: fix a file leak in kvm_vcpu_ioctl_enable_cap() 2024-08-19 05:33:42 +02:00
lib powerpc/code-patching: Fix KASAN hit by not flagging text patching area as VM_ALLOC 2025-03-13 12:43:22 +01:00
math-emu powerpc/math_emu/efp: Include module.h 2022-10-26 13:22:44 +02:00
mm powerpc: pmd_move_must_withdraw() is only needed for CONFIG_TRANSPARENT_HUGEPAGE 2024-02-23 08:24:53 +01:00
net powerpc/bpf: Emit stf barrier instruction sequences for BPF_NOSPEC 2021-11-17 09:48:49 +01:00
oprofile
perf powerpc/hv-gpci: Fix the H_GET_PERF_COUNTER_INFO hcall return value checks 2024-03-26 18:22:22 -04:00
platforms powerpc/pseries/eeh: Fix get PE state translation 2025-03-13 12:43:09 +01:00
purgatory powerpc/purgatory: remove PGO flags 2023-06-21 15:44:10 +02:00
sysdev powerpc/xics: Check return value of kasprintf in icp_native_map_one_cpu 2024-09-04 13:14:54 +02:00
tools powerpc: Do not consider weak unresolved symbol relocations as bad 2020-02-24 08:37:00 +01:00
xmon powerpc/xmon: Fix disassembly CPU feature checks 2024-08-19 05:33:33 +02:00
Kbuild
Kconfig powerpc: Fix HAVE_HARDLOCKUP_DETECTOR_ARCH build configuration 2021-05-14 09:44:26 +02:00
Kconfig.debug powerpc: allow PPC_EARLY_DEBUG_CPM only when SERIAL_CPM=y 2023-07-27 08:37:23 +02:00
Makefile powerpc: Fail build if using recordmcount with binutils v2.37 2023-07-27 08:37:34 +02:00
Makefile.postlink powerpc: Do not consider weak unresolved symbol relocations as bad 2020-02-24 08:37:00 +01:00