locking/lockdep: check for freed initmem in static_obj()
authorGerald Schaefer <gerald.schaefer@de.ibm.com>
Thu, 18 Apr 2019 14:24:50 +0000 (16:24 +0200)
committerMartin Schwidefsky <schwidefsky@de.ibm.com>
Mon, 29 Apr 2019 08:47:10 +0000 (10:47 +0200)
commit7a5da02de8d6eafba99556f8c98e5313edebb449
treea65d2d59ec15717701fdb00a82dafeb418726593
parentb2d24b97b2a9691351920e700bfda4368c177232
locking/lockdep: check for freed initmem in static_obj()

The following warning occurred on s390:
WARNING: CPU: 0 PID: 804 at kernel/locking/lockdep.c:1025 lockdep_register_key+0x30/0x150

This is because the check in static_obj() assumes that all memory within
[_stext, _end] belongs to static objects, which at least for s390 isn't
true. The init section is also part of this range, and freeing it allows
the buddy allocator to allocate memory from it. We have virt == phys for
the kernel on s390, so that such allocations would then have addresses
within the range [_stext, _end].

To fix this, introduce arch_is_kernel_initmem_freed(), similar to
arch_is_kernel_text/data(), and add it to the checks in static_obj().
This will always return 0 on architectures that do not define
arch_is_kernel_initmem_freed. On s390, it will return 1 if initmem has
been freed and the address is in the range [__init_begin, __init_end].

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
arch/s390/include/asm/sections.h
arch/s390/mm/init.c
include/asm-generic/sections.h
kernel/locking/lockdep.c