4.19-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit c61c7def1fa0a722610d89790e0255b74f3c07dd ]
Commit ea7e0480a4b6 ("MIPS: VDSO: Always map near top of user memory")
set VDSO_RANDOMIZE_SIZE to 256MB for 64bit kernel. But take a look at
arch/mips/mm/mmap.c we can see that MIN_GAP is 128MB, which means the
mmap_base may be at (user_address_top - 128MB). This make the stack be
surrounded by mmaped areas, then stack expanding fails and causes a
segmentation fault. Therefore, VDSO_RANDOMIZE_SIZE should be less than
MIN_GAP and this patch reduce it to 64MB.
Signed-off-by: Huacai Chen <[email protected]>
Signed-off-by: Paul Burton <[email protected]>
Fixes: ea7e0480a4b6 ("MIPS: VDSO: Always map near top of user memory")
Patchwork: https://patchwork.linux-mips.org/patch/20910/
Cc: Ralf Baechle <[email protected]>
Cc: James Hogan <[email protected]>
Cc: [email protected]
Cc: Fuxin Zhang <[email protected]>
Cc: Zhangjin Wu <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: [email protected] # 4.19
Signed-off-by: Sasha Levin <[email protected]>
---
arch/mips/include/asm/processor.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/mips/include/asm/processor.h
b/arch/mips/include/asm/processor.h
index 49d6046ca1d0..c373eb605040 100644
--- a/arch/mips/include/asm/processor.h
+++ b/arch/mips/include/asm/processor.h
@@ -81,7 +81,7 @@ extern unsigned int vced_count, vcei_count;
#endif
-#define VDSO_RANDOMIZE_SIZE (TASK_IS_32BIT_ADDR ? SZ_1M : SZ_256M)
+#define VDSO_RANDOMIZE_SIZE (TASK_IS_32BIT_ADDR ? SZ_1M : SZ_64M)
extern unsigned long mips_stack_top(void);
#define STACK_TOP mips_stack_top()
--
2.17.1
