* Jeremy Fitzhardinge <jeremy@sw.oz.au>
*/
-/*
- * The purpose of always_dump_vma() is to make sure that special kernel mappings
- * that are useful for post-mortem analysis are included in every core dump.
- * In that way we ensure that the core dump is fully interpretable later
- * without matching up the same kernel and hardware config to see what PC values
- * meant. These special mappings include - vDSO, vsyscall, and other
- * architecture specific mappings
- */
-static bool always_dump_vma(struct vm_area_struct *vma)
-{
- /* Any vsyscall mappings? */
- if (vma == get_gate_vma(vma->vm_mm))
- return true;
-
- /*
- * Assume that all vmas with a .name op should always be dumped.
- * If this changes, a new vm_ops field can easily be added.
- */
- if (vma->vm_ops && vma->vm_ops->name && vma->vm_ops->name(vma))
- return true;
-
- /*
- * arch_vma_name() returns non-NULL for special architecture mappings,
- * such as vDSO sections.
- */
- if (arch_vma_name(vma))
- return true;
-
- return false;
-}
-
-/*
- * Decide what to dump of a segment, part, all or none.
- */
-static unsigned long vma_dump_size(struct vm_area_struct *vma,
- unsigned long mm_flags)
-{
-#define FILTER(type) (mm_flags & (1UL << MMF_DUMP_##type))
-
- /* always dump the vdso and vsyscall sections */
- if (always_dump_vma(vma))
- goto whole;
-
- if (vma->vm_flags & VM_DONTDUMP)
- return 0;
-
- /* support for DAX */
- if (vma_is_dax(vma)) {
- if ((vma->vm_flags & VM_SHARED) && FILTER(DAX_SHARED))
- goto whole;
- if (!(vma->vm_flags & VM_SHARED) && FILTER(DAX_PRIVATE))
- goto whole;
- return 0;
- }
-
- /* Hugetlb memory check */
- if (is_vm_hugetlb_page(vma)) {
- if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED))
- goto whole;
- if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE))
- goto whole;
- return 0;
- }
-
- /* Do not dump I/O mapped devices or special mappings */
- if (vma->vm_flags & VM_IO)
- return 0;
-
- /* By default, dump shared memory if mapped from an anonymous file. */
- if (vma->vm_flags & VM_SHARED) {
- if (file_inode(vma->vm_file)->i_nlink == 0 ?
- FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED))
- goto whole;
- return 0;
- }
-
- /* Dump segments that have been written to. */
- if (vma->anon_vma && FILTER(ANON_PRIVATE))
- goto whole;
- if (vma->vm_file == NULL)
- return 0;
-
- if (FILTER(MAPPED_PRIVATE))
- goto whole;
-
- /*
- * If this looks like the beginning of a DSO or executable mapping,
- * check for an ELF header. If we find one, dump the first page to
- * aid in determining what was mapped here.
- */
- if (FILTER(ELF_HEADERS) &&
- vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) {
- u32 __user *header = (u32 __user *) vma->vm_start;
- u32 word;
- /*
- * Doing it this way gets the constant folded by GCC.
- */
- union {
- u32 cmp;
- char elfmag[SELFMAG];
- } magic;
- BUILD_BUG_ON(SELFMAG != sizeof word);
- magic.elfmag[EI_MAG0] = ELFMAG0;
- magic.elfmag[EI_MAG1] = ELFMAG1;
- magic.elfmag[EI_MAG2] = ELFMAG2;
- magic.elfmag[EI_MAG3] = ELFMAG3;
- if (unlikely(get_user(word, header)))
- word = 0;
- if (word == magic.cmp)
- return PAGE_SIZE;
- }
-
-#undef FILTER
-
- return 0;
-
-whole:
- return vma->vm_end - vma->vm_start;
-}
-
/* An ELF note in memory */
struct memelfnote
{
int pr_fpvalid; /* True if math co-processor being used. */
};
-/*
- * Decide whether a segment is worth dumping; default is yes to be
- * sure (missing info is worse than too much; etc).
- * Personally I'd include everything, and use the coredump limit...
- *
- * I think we should skip something. But I am not sure how. H.J.
- */
-static int maydump(struct vm_area_struct *vma, unsigned long mm_flags)
-{
- int dump_ok;
-
- /* Do not dump I/O mapped devices or special mappings */
- if (vma->vm_flags & VM_IO) {
- kdcore("%08lx: %08lx: no (IO)", vma->vm_start, vma->vm_flags);
- return 0;
- }
-
- /* If we may not read the contents, don't allow us to dump
- * them either. "dump_write()" can't handle it anyway.
- */
- if (!(vma->vm_flags & VM_READ)) {
- kdcore("%08lx: %08lx: no (!read)", vma->vm_start, vma->vm_flags);
- return 0;
- }
-
- /* support for DAX */
- if (vma_is_dax(vma)) {
- if (vma->vm_flags & VM_SHARED) {
- dump_ok = test_bit(MMF_DUMP_DAX_SHARED, &mm_flags);
- kdcore("%08lx: %08lx: %s (DAX shared)", vma->vm_start,
- vma->vm_flags, dump_ok ? "yes" : "no");
- } else {
- dump_ok = test_bit(MMF_DUMP_DAX_PRIVATE, &mm_flags);
- kdcore("%08lx: %08lx: %s (DAX private)", vma->vm_start,
- vma->vm_flags, dump_ok ? "yes" : "no");
- }
- return dump_ok;
- }
-
- /* By default, dump shared memory if mapped from an anonymous file. */
- if (vma->vm_flags & VM_SHARED) {
- if (file_inode(vma->vm_file)->i_nlink == 0) {
- dump_ok = test_bit(MMF_DUMP_ANON_SHARED, &mm_flags);
- kdcore("%08lx: %08lx: %s (share)", vma->vm_start,
- vma->vm_flags, dump_ok ? "yes" : "no");
- return dump_ok;
- }
-
- dump_ok = test_bit(MMF_DUMP_MAPPED_SHARED, &mm_flags);
- kdcore("%08lx: %08lx: %s (share)", vma->vm_start,
- vma->vm_flags, dump_ok ? "yes" : "no");
- return dump_ok;
- }
-
-#ifdef CONFIG_MMU
- /* By default, if it hasn't been written to, don't write it out */
- if (!vma->anon_vma) {
- dump_ok = test_bit(MMF_DUMP_MAPPED_PRIVATE, &mm_flags);
- kdcore("%08lx: %08lx: %s (!anon)", vma->vm_start,
- vma->vm_flags, dump_ok ? "yes" : "no");
- return dump_ok;
- }
-#endif
-
- dump_ok = test_bit(MMF_DUMP_ANON_PRIVATE, &mm_flags);
- kdcore("%08lx: %08lx: %s", vma->vm_start, vma->vm_flags,
- dump_ok ? "yes" : "no");
- return dump_ok;
-}
-
/* An ELF note in memory */
struct memelfnote
{
struct vm_area_struct *vma;
for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
- unsigned long addr;
-
- if (!maydump(vma, cprm->mm_flags))
- continue;
+ unsigned long size = vma_dump_size(vma, cprm->mm_flags);
- if (!dump_user_range(cprm, vma->vm_start,
- vma->vma_end - vma->vm_start))
+ if (!dump_user_range(cprm, vma->vm_start, size))
return false;
}
return true;
size_t size = 0;
for (vma = current->mm->mmap; vma; vma = vma->vm_next)
- if (maydump(vma, mm_flags))
- size += vma->vm_end - vma->vm_start;
+ size += vma_dump_size(vma, mm_flags);
return size;
}
phdr.p_offset = offset;
phdr.p_vaddr = vma->vm_start;
phdr.p_paddr = 0;
- phdr.p_filesz = maydump(vma, cprm->mm_flags) ? sz : 0;
+ phdr.p_filesz = vma_dump_size(vma, cprm->mm_flags);
phdr.p_memsz = sz;
offset += phdr.p_filesz;
phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
}
}
EXPORT_SYMBOL(dump_truncate);
+
+/*
+ * The purpose of always_dump_vma() is to make sure that special kernel mappings
+ * that are useful for post-mortem analysis are included in every core dump.
+ * In that way we ensure that the core dump is fully interpretable later
+ * without matching up the same kernel and hardware config to see what PC values
+ * meant. These special mappings include - vDSO, vsyscall, and other
+ * architecture specific mappings
+ */
+static bool always_dump_vma(struct vm_area_struct *vma)
+{
+ /* Any vsyscall mappings? */
+ if (vma == get_gate_vma(vma->vm_mm))
+ return true;
+
+ /*
+ * Assume that all vmas with a .name op should always be dumped.
+ * If this changes, a new vm_ops field can easily be added.
+ */
+ if (vma->vm_ops && vma->vm_ops->name && vma->vm_ops->name(vma))
+ return true;
+
+ /*
+ * arch_vma_name() returns non-NULL for special architecture mappings,
+ * such as vDSO sections.
+ */
+ if (arch_vma_name(vma))
+ return true;
+
+ return false;
+}
+
+/*
+ * Decide how much of @vma's contents should be included in a core dump.
+ */
+unsigned long vma_dump_size(struct vm_area_struct *vma, unsigned long mm_flags)
+{
+#define FILTER(type) (mm_flags & (1UL << MMF_DUMP_##type))
+
+ /* always dump the vdso and vsyscall sections */
+ if (always_dump_vma(vma))
+ goto whole;
+
+ if (vma->vm_flags & VM_DONTDUMP)
+ return 0;
+
+ /* support for DAX */
+ if (vma_is_dax(vma)) {
+ if ((vma->vm_flags & VM_SHARED) && FILTER(DAX_SHARED))
+ goto whole;
+ if (!(vma->vm_flags & VM_SHARED) && FILTER(DAX_PRIVATE))
+ goto whole;
+ return 0;
+ }
+
+ /* Hugetlb memory check */
+ if (is_vm_hugetlb_page(vma)) {
+ if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED))
+ goto whole;
+ if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE))
+ goto whole;
+ return 0;
+ }
+
+ /* Do not dump I/O mapped devices or special mappings */
+ if (vma->vm_flags & VM_IO)
+ return 0;
+
+ /* By default, dump shared memory if mapped from an anonymous file. */
+ if (vma->vm_flags & VM_SHARED) {
+ if (file_inode(vma->vm_file)->i_nlink == 0 ?
+ FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED))
+ goto whole;
+ return 0;
+ }
+
+ /* Dump segments that have been written to. */
+ if ((!IS_ENABLED(CONFIG_MMU) || vma->anon_vma) && FILTER(ANON_PRIVATE))
+ goto whole;
+ if (vma->vm_file == NULL)
+ return 0;
+
+ if (FILTER(MAPPED_PRIVATE))
+ goto whole;
+
+ /*
+ * If this is the beginning of an executable file mapping,
+ * dump the first page to aid in determining what was mapped here.
+ */
+ if (FILTER(ELF_HEADERS) &&
+ vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ) &&
+ (READ_ONCE(file_inode(vma->vm_file)->i_mode) & 0111) != 0)
+ return PAGE_SIZE;
+
+#undef FILTER
+
+ return 0;
+
+whole:
+ return vma->vm_end - vma->vm_start;
+}
extern int dump_emit(struct coredump_params *cprm, const void *addr, int nr);
extern int dump_align(struct coredump_params *cprm, int align);
extern void dump_truncate(struct coredump_params *cprm);
+unsigned long vma_dump_size(struct vm_area_struct *vma, unsigned long mm_flags);
int dump_user_range(struct coredump_params *cprm, unsigned long start,
unsigned long len);
#ifdef CONFIG_COREDUMP
projects / thirdparty / linux.git / commitdiff
