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bac59d18c7
When booting x86 images in qemu, the following warning is seen randomly
if DEBUG_LOCKDEP is enabled.
WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:1119
lockdep_register_key+0xc0/0x100
static_obj() returns true if an address is between _stext and _end.
On x86, this includes the brk memory space. Problem is that this memory
block is not static on x86; its unused portions are released after init
and can be allocated. This results in the observed warning if a lockdep
object is allocated from this memory.
Solve the problem by implementing arch_is_kernel_initmem_freed() for
x86 and have it return true if an address is within the released memory
range.
The same problem was solved for s390 with commit
7a5da02de8 ("locking/lockdep: check for freed initmem in static_obj()"),
which introduced arch_is_kernel_initmem_freed().
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200131021159.9178-1-linux@roeck-us.net
38 lines
895 B
C
38 lines
895 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_SECTIONS_H
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#define _ASM_X86_SECTIONS_H
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#define arch_is_kernel_initmem_freed arch_is_kernel_initmem_freed
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#include <asm-generic/sections.h>
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#include <asm/extable.h>
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extern char __brk_base[], __brk_limit[];
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extern char __end_rodata_aligned[];
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#if defined(CONFIG_X86_64)
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extern char __end_rodata_hpage_align[];
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#endif
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extern char __end_of_kernel_reserve[];
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extern unsigned long _brk_start, _brk_end;
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static inline bool arch_is_kernel_initmem_freed(unsigned long addr)
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{
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/*
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* If _brk_start has not been cleared, brk allocation is incomplete,
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* and we can not make assumptions about its use.
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*/
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if (_brk_start)
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return 0;
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/*
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* After brk allocation is complete, space between _brk_end and _end
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* is available for allocation.
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*/
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return addr >= _brk_end && addr < (unsigned long)&_end;
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}
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#endif /* _ASM_X86_SECTIONS_H */
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