Re: [PATCHv5 2/3] x86/vdso: add mremap hook to vm_special_mapping

[kbuild test robot <lkp@intel.com>]

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Hi Dmitry,

[auto build test WARNING on v4.6-rc4]
[also build test WARNING on next-20160418]
[cannot apply to tip/x86/core tip/x86/vdso]
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]

url:    https://github.com/0day-ci/linux/commits/Dmitry-Safonov/x86-rename-is_-ia32-x32-_task-to-in_-ia32-x32-_syscall/20160418-214656
config: x86_64-randconfig-x000-201616 (attached as .config)
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All warnings (new ones prefixed by >>):

   In file included from include/asm-generic/bug.h:4:0,
                    from arch/x86/include/asm/bug.h:35,
                    from include/linux/bug.h:4,
                    from include/linux/mmdebug.h:4,
                    from include/linux/mm.h:8,
                    from arch/x86/entry/vdso/vma.c:7:
   arch/x86/entry/vdso/vma.c: In function 'vdso_mremap':
   arch/x86/entry/vdso/vma.c:114:37: error: 'vdso_image_32' undeclared (first use in this function)
     if (in_ia32_syscall() && image == &vdso_image_32) {
                                        ^
   include/linux/compiler.h:151:30: note: in definition of macro '__trace_if'
     if (__builtin_constant_p(!!(cond)) ? !!(cond) :   \
                                 ^
>> arch/x86/entry/vdso/vma.c:114:2: note: in expansion of macro 'if'
     if (in_ia32_syscall() && image == &vdso_image_32) {
     ^
   arch/x86/entry/vdso/vma.c:114:37: note: each undeclared identifier is reported only once for each function it appears in
     if (in_ia32_syscall() && image == &vdso_image_32) {
                                        ^
   include/linux/compiler.h:151:30: note: in definition of macro '__trace_if'
     if (__builtin_constant_p(!!(cond)) ? !!(cond) :   \
                                 ^
>> arch/x86/entry/vdso/vma.c:114:2: note: in expansion of macro 'if'
     if (in_ia32_syscall() && image == &vdso_image_32) {
     ^

vim +/if +114 arch/x86/entry/vdso/vma.c

     1	/*
     2	 * Copyright 2007 Andi Kleen, SUSE Labs.
     3	 * Subject to the GPL, v.2
     4	 *
     5	 * This contains most of the x86 vDSO kernel-side code.
     6	 */
   > 7	#include <linux/mm.h>
     8	#include <linux/err.h>
     9	#include <linux/sched.h>
    10	#include <linux/slab.h>
    11	#include <linux/init.h>
    12	#include <linux/random.h>
    13	#include <linux/elf.h>
    14	#include <linux/cpu.h>
    15	#include <linux/ptrace.h>
    16	#include <asm/pvclock.h>
    17	#include <asm/vgtod.h>
    18	#include <asm/proto.h>
    19	#include <asm/vdso.h>
    20	#include <asm/vvar.h>
    21	#include <asm/page.h>
    22	#include <asm/hpet.h>
    23	#include <asm/desc.h>
    24	#include <asm/cpufeature.h>
    25	
    26	#if defined(CONFIG_X86_64)
    27	unsigned int __read_mostly vdso64_enabled = 1;
    28	#endif
    29	
    30	void __init init_vdso_image(const struct vdso_image *image)
    31	{
    32		BUG_ON(image->size % PAGE_SIZE != 0);
    33	
    34		apply_alternatives((struct alt_instr *)(image->data + image->alt),
    35				   (struct alt_instr *)(image->data + image->alt +
    36							image->alt_len));
    37	}
    38	
    39	struct linux_binprm;
    40	
    41	/*
    42	 * Put the vdso above the (randomized) stack with another randomized
    43	 * offset.  This way there is no hole in the middle of address space.
    44	 * To save memory make sure it is still in the same PTE as the stack
    45	 * top.  This doesn't give that many random bits.
    46	 *
    47	 * Note that this algorithm is imperfect: the distribution of the vdso
    48	 * start address within a PMD is biased toward the end.
    49	 *
    50	 * Only used for the 64-bit and x32 vdsos.
    51	 */
    52	static unsigned long vdso_addr(unsigned long start, unsigned len)
    53	{
    54	#ifdef CONFIG_X86_32
    55		return 0;
    56	#else
    57		unsigned long addr, end;
    58		unsigned offset;
    59	
    60		/*
    61		 * Round up the start address.  It can start out unaligned as a result
    62		 * of stack start randomization.
    63		 */
    64		start = PAGE_ALIGN(start);
    65	
    66		/* Round the lowest possible end address up to a PMD boundary. */
    67		end = (start + len + PMD_SIZE - 1) & PMD_MASK;
    68		if (end >= TASK_SIZE_MAX)
    69			end = TASK_SIZE_MAX;
    70		end -= len;
    71	
    72		if (end > start) {
    73			offset = get_random_int() % (((end - start) >> PAGE_SHIFT) + 1);
    74			addr = start + (offset << PAGE_SHIFT);
    75		} else {
    76			addr = start;
    77		}
    78	
    79		/*
    80		 * Forcibly align the final address in case we have a hardware
    81		 * issue that requires alignment for performance reasons.
    82		 */
    83		addr = align_vdso_addr(addr);
    84	
    85		return addr;
    86	#endif
    87	}
    88	
    89	static int vdso_fault(const struct vm_special_mapping *sm,
    90			      struct vm_area_struct *vma, struct vm_fault *vmf)
    91	{
    92		const struct vdso_image *image = vma->vm_mm->context.vdso_image;
    93	
    94		if (!image || (vmf->pgoff << PAGE_SHIFT) >= image->size)
    95			return VM_FAULT_SIGBUS;
    96	
    97		vmf->page = virt_to_page(image->data + (vmf->pgoff << PAGE_SHIFT));
    98		get_page(vmf->page);
    99		return 0;
   100	}
   101	
   102	static int vdso_mremap(const struct vm_special_mapping *sm,
   103			      struct vm_area_struct *new_vma)
   104	{
   105		unsigned long new_size = new_vma->vm_end - new_vma->vm_start;
   106		const struct vdso_image *image = current->mm->context.vdso_image;
   107	
   108		if (image->size != new_size)
   109			return -EINVAL;
   110	
   111		if (current->mm != new_vma->vm_mm)
   112			return -EFAULT;
   113	
 > 114		if (in_ia32_syscall() && image == &vdso_image_32) {
   115			struct pt_regs *regs = current_pt_regs();
   116			unsigned long vdso_land = image->sym_int80_landing_pad;
   117			unsigned long old_land_addr = vdso_land +

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0-DAY kernel test infrastructure                Open Source Technology Center
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