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>

1 files changed, 12 insertions, 0 deletions

diff --git a/arch/s390/include/asm/sections.h b/arch/s390/include/asm/sections.h
index af670fa4b12a..42de04ad9c07 100644
--- a/arch/s390/include/asm/sections.h
+++ b/arch/s390/include/asm/sections.h
@@ -2,8 +2,20 @@
 #ifndef _S390_SECTIONS_H
 #define _S390_SECTIONS_H
 
+#define arch_is_kernel_initmem_freed arch_is_kernel_initmem_freed
+
 #include <asm-generic/sections.h>
 
+extern bool initmem_freed;
+
+static inline int arch_is_kernel_initmem_freed(unsigned long addr)
+{
+	if (!initmem_freed)
+		return 0;
+	return addr >= (unsigned long)__init_begin &&
+	       addr < (unsigned long)__init_end;
+}
+
 /*
  * .boot.data section contains variables "shared" between the decompressor and
  * the decompressed kernel. The decompressor will store values in them, and