CVE-2025-38320: In the Linux kernel, the following vulnerability has been resolved:  arm64/ptrace: Fix stack-out-of-bounds read in regs_get_kernel_stack_nth()  KASAN reports a stack-out-of-bounds read in regs_get_kernel_stack_nth().  Call Trace: [   97.283505] BUG: KASAN: stack-out-of-bounds in regs_get_kernel_stack_nth+0xa8/0xc8 [   97.284677] Read of size 8 at addr ffff800089277c10 by task 1.sh/2550 [   97.285732] [   97.286067] CPU: 7 PID: 2550 Comm: 1.sh Not tainted 6.6.0+ #11 [   97.287032] Hardware name: linux,dummy-virt (DT) [   97.287815] Call trace: [   97.288279]  dump_backtrace+0xa0/0x128 [   97.288946]  show_stack+0x20/0x38 [   97.289551]  dump_stack_lvl+0x78/0xc8 [   97.290203]  print_address_description.constprop.0+0x84/0x3c8 [   97.291159]  print_report+0xb0/0x280 [   97.291792]  kasan_report+0x84/0xd0 [   97.292421]  __asan_load8+0x9c/0xc0 [   97.293042]  regs_get_kernel_stack_nth+0xa8/0xc8 [   97.293835]  process_fetch_insn+0x770/0xa30 [   97.294562]  kprobe_trace_func+0x254/0x3b0 [   97.295271]  kprobe_dispatcher+0x98/0xe0 [   97.295955]  kprobe_breakpoint_handler+0x1b0/0x210 [   97.296774]  call_break_hook+0xc4/0x100 [   97.297451]  brk_handler+0x24/0x78 [   97.298073]  do_debug_exception+0xac/0x178 [   97.298785]  el1_dbg+0x70/0x90 [   97.299344]  el1h_64_sync_handler+0xcc/0xe8 [   97.300066]  el1h_64_sync+0x78/0x80 [   97.300699]  kernel_clone+0x0/0x500 [   97.301331]  __arm64_sys_clone+0x70/0x90 [   97.302084]  invoke_syscall+0x68/0x198 [   97.302746]  el0_svc_common.constprop.0+0x11c/0x150 [   97.303569]  do_el0_svc+0x38/0x50 [   97.304164]  el0_svc+0x44/0x1d8 [   97.304749]  el0t_64_sync_handler+0x100/0x130 [   97.305500]  el0t_64_sync+0x188/0x190 [   97.306151] [   97.306475] The buggy address belongs to stack of task 1.sh/2550 [   97.307461]  and is located at offset 0 in frame: [   97.308257]  __se_sys_clone+0x0/0x138 [   97.308910] [   97.309241] This frame has 1 object: [   97.309873]  [48, 184) 'args' [   97.309876] [   97.310749] The buggy address belongs to the virtual mapping at [   97.310749]  [ffff800089270000, ffff800089279000) created by: [   97.310749]  dup_task_struct+0xc0/0x2e8 [   97.313347] [   97.313674] The buggy address belongs to the physical page: [   97.314604] page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x14f69a [   97.315885] flags: 0x15ffffe00000000(node=1|zone=2|lastcpupid=0xfffff) [   97.316957] raw: 015ffffe00000000 0000000000000000 dead000000000122 0000000000000000 [   97.318207] raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 [   97.319445] page dumped because: kasan: bad access detected [   97.320371] [   97.320694] Memory state around the buggy address: [   97.321511]  ffff800089277b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [   97.322681]  ffff800089277b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [   97.323846] >ffff800089277c00: 00 00 f1 f1 f1 f1 f1 f1 00 00 00 00 00 00 00 00 [   97.325023]                          ^ [   97.325683]  ffff800089277c80: 00 00 00 00 00 00 00 00 00 f3 f3 f3 f3 f3 f3 f3 [   97.326856]  ffff800089277d00: f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00  This issue seems to be related to the behavior of some gcc compilers and was also fixed on the s390 architecture before:   commit d93a855c31b7 ("s390/ptrace: Avoid KASAN false positives in regs_get_kernel_stack_nth()")  As described in that commit, regs_get_kernel_stack_nth() has confirmed that `addr` is on the stack, so reading the value at `*addr` should be allowed. Use READ_ONCE_NOCHECK() helper to silence the KASAN check for this case.  [will: Use '*addr' as the argument to READ_ONCE_NOCHECK()]