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| author |   Guenter Roeck <linux@roeck-us.net> | 2020-01-30 18:11:59 -0800 |
|---|---|---|
| committer |   Borislav Petkov <bp@suse.de> | 2020-03-19 11:58:13 +0100 |
| commit | bac59d18c7018a2fd5e800a1e72a8271bf404977 (patch) | |
| tree | 7d047657b3491b41a1049a2aff514c7ef141b369 /arch/x86/include/asm/sections.h | |
| parent | x86/vmlinux: Drop unneeded linker script discard of .eh_frame (diff) | |
| download | linux-dev-bac59d18c7018a2fd5e800a1e72a8271bf404977.tar.xz linux-dev-bac59d18c7018a2fd5e800a1e72a8271bf404977.zip | |
x86/setup: Fix static memory detection
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
7a5da02de8d6e ("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
Diffstat (limited to 'arch/x86/include/asm/sections.h')
| -rw-r--r-- | arch/x86/include/asm/sections.h | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/arch/x86/include/asm/sections.h b/arch/x86/include/asm/sections.h index 036c360910c5..a6e8373a5170 100644 --- a/arch/x86/include/asm/sections.h +++ b/arch/x86/include/asm/sections.h @@ -2,6 +2,8 @@ #ifndef _ASM_X86_SECTIONS_H #define _ASM_X86_SECTIONS_H +#define arch_is_kernel_initmem_freed arch_is_kernel_initmem_freed + #include <asm-generic/sections.h> #include <asm/extable.h> @@ -14,4 +16,22 @@ extern char __end_rodata_hpage_align[]; extern char __end_of_kernel_reserve[]; +extern unsigned long _brk_start, _brk_end; + +static inline bool arch_is_kernel_initmem_freed(unsigned long addr) +{ + /* + * If _brk_start has not been cleared, brk allocation is incomplete, + * and we can not make assumptions about its use. + */ + if (_brk_start) + return 0; + + /* + * After brk allocation is complete, space between _brk_end and _end + * is available for allocation. + */ + return addr >= _brk_end && addr < (unsigned long)&_end; +} + #endif /* _ASM_X86_SECTIONS_H */ |