Revert "parisc: Fix backtrace to always include init funtion names"
authorHelge Deller <deller@gmx.de>
Sun, 21 Nov 2021 10:10:55 +0000 (11:10 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 1 Dec 2021 08:04:41 +0000 (09:04 +0100)
commit28849ab40bac4e8bfa5be1b9017091af4b135071
tree6b46ff3c06689098903fc6d9c531c861bd248464
parent02130f5e7ca3770daf2a086b3bee22134901a488
Revert "parisc: Fix backtrace to always include init funtion names"

commit 98400ad75e95860e9a10ec78b0b90ab66184a2ce upstream.

This reverts commit 279917e27edc293eb645a25428c6ab3f3bca3f86.

With the CONFIG_HARDENED_USERCOPY option enabled, this patch triggers
kernel bugs at runtime:

  usercopy: Kernel memory overwrite attempt detected to kernel text (offset 2084839, size 6)!
  kernel BUG at mm/usercopy.c:99!
 Backtrace:
  IAOQ[0]: usercopy_abort+0xc4/0xe8
  [<00000000406ed1c8>] __check_object_size+0x174/0x238
  [<00000000407086d4>] copy_strings.isra.0+0x3e8/0x708
  [<0000000040709a20>] do_execveat_common.isra.0+0x1bc/0x328
  [<000000004070b760>] compat_sys_execve+0x7c/0xb8
  [<0000000040303eb8>] syscall_exit+0x0/0x14

The problem is, that we have an init section of at least 2MB size which
starts at _stext and is freed after bootup.

If then later some kernel data is (temporarily) stored in this free
memory, check_kernel_text_object() will trigger a bug since the data
appears to be inside the kernel text (>=_stext) area:
        if (overlaps(ptr, len, _stext, _etext))
                usercopy_abort("kernel text");

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@kernel.org # 5.4+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/parisc/kernel/vmlinux.lds.S