Re: [PATCH v4] fs/coredump: Enable dynamic configuration of max file note size
From: Allen
Date: Tue May 07 2024 - 12:43:03 EST
>
> kernel test robot noticed the following build errors:
>
> [auto build test ERROR on kees/for-next/execve]
> [also build test ERROR on brauner-vfs/vfs.all linus/master v6.9-rc7 next-20240507]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
>
> url: https://github.com/intel-lab-lkp/linux/commits/Allen-Pais/fs-coredump-Enable-dynamic-configuration-of-max-file-note-size/20240507-033907
> base: https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/execve
> patch link: https://lore.kernel.org/r/20240506193700.7884-1-apais%40linux.microsoft.com
> patch subject: [PATCH v4] fs/coredump: Enable dynamic configuration of max file note size
> config: loongarch-randconfig-001-20240507 (https://download.01.org/0day-ci/archive/20240507/202405072249.fLkavX40-lkp@xxxxxxxxx/config)
> compiler: loongarch64-linux-gcc (GCC) 13.2.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240507/202405072249.fLkavX40-lkp@xxxxxxxxx/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@xxxxxxxxx>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202405072249.fLkavX40-lkp@xxxxxxxxx/
>
Thanks for reporting. The kernel builds fine with
https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git
for-next/execve.
The issue is with loongarch-randconfig, which has CONFIG_SYSCTL set to
"n". It is needed for this patch.
Thanks,
Allen
> All errors (new ones prefixed by >>):
>
> fs/binfmt_elf.c: In function 'fill_files_note':
> >> fs/binfmt_elf.c:1598:21: error: 'core_file_note_size_min' undeclared (first use in this function)
> 1598 | if (size >= core_file_note_size_min) {
> | ^~~~~~~~~~~~~~~~~~~~~~~
> fs/binfmt_elf.c:1598:21: note: each undeclared identifier is reported only once for each function it appears in
>
>
> vim +/core_file_note_size_min +1598 fs/binfmt_elf.c
>
> 1569
> 1570 /*
> 1571 * Format of NT_FILE note:
> 1572 *
> 1573 * long count -- how many files are mapped
> 1574 * long page_size -- units for file_ofs
> 1575 * array of [COUNT] elements of
> 1576 * long start
> 1577 * long end
> 1578 * long file_ofs
> 1579 * followed by COUNT filenames in ASCII: "FILE1" NUL "FILE2" NUL...
> 1580 */
> 1581 static int fill_files_note(struct memelfnote *note, struct coredump_params *cprm)
> 1582 {
> 1583 unsigned count, size, names_ofs, remaining, n;
> 1584 user_long_t *data;
> 1585 user_long_t *start_end_ofs;
> 1586 char *name_base, *name_curpos;
> 1587 int i;
> 1588
> 1589 /* *Estimated* file count and total data size needed */
> 1590 count = cprm->vma_count;
> 1591 if (count > UINT_MAX / 64)
> 1592 return -EINVAL;
> 1593 size = count * 64;
> 1594
> 1595 names_ofs = (2 + 3 * count) * sizeof(data[0]);
> 1596 alloc:
> 1597 /* paranoia check */
> > 1598 if (size >= core_file_note_size_min) {
> 1599 pr_warn_once("coredump Note size too large: %u (does kernel.core_file_note_size_min sysctl need adjustment?\n",
> 1600 size);
> 1601 return -EINVAL;
> 1602 }
> 1603 size = round_up(size, PAGE_SIZE);
> 1604 /*
> 1605 * "size" can be 0 here legitimately.
> 1606 * Let it ENOMEM and omit NT_FILE section which will be empty anyway.
> 1607 */
> 1608 data = kvmalloc(size, GFP_KERNEL);
> 1609 if (ZERO_OR_NULL_PTR(data))
> 1610 return -ENOMEM;
> 1611
> 1612 start_end_ofs = data + 2;
> 1613 name_base = name_curpos = ((char *)data) + names_ofs;
> 1614 remaining = size - names_ofs;
> 1615 count = 0;
> 1616 for (i = 0; i < cprm->vma_count; i++) {
> 1617 struct core_vma_metadata *m = &cprm->vma_meta[i];
> 1618 struct file *file;
> 1619 const char *filename;
> 1620
> 1621 file = m->file;
> 1622 if (!file)
> 1623 continue;
> 1624 filename = file_path(file, name_curpos, remaining);
> 1625 if (IS_ERR(filename)) {
> 1626 if (PTR_ERR(filename) == -ENAMETOOLONG) {
> 1627 kvfree(data);
> 1628 size = size * 5 / 4;
> 1629 goto alloc;
> 1630 }
> 1631 continue;
> 1632 }
> 1633
> 1634 /* file_path() fills at the end, move name down */
> 1635 /* n = strlen(filename) + 1: */
> 1636 n = (name_curpos + remaining) - filename;
> 1637 remaining = filename - name_curpos;
> 1638 memmove(name_curpos, filename, n);
> 1639 name_curpos += n;
> 1640
> 1641 *start_end_ofs++ = m->start;
> 1642 *start_end_ofs++ = m->end;
> 1643 *start_end_ofs++ = m->pgoff;
> 1644 count++;
> 1645 }
> 1646
> 1647 /* Now we know exact count of files, can store it */
> 1648 data[0] = count;
> 1649 data[1] = PAGE_SIZE;
> 1650 /*
> 1651 * Count usually is less than mm->map_count,
> 1652 * we need to move filenames down.
> 1653 */
> 1654 n = cprm->vma_count - count;
> 1655 if (n != 0) {
> 1656 unsigned shift_bytes = n * 3 * sizeof(data[0]);
> 1657 memmove(name_base - shift_bytes, name_base,
> 1658 name_curpos - name_base);
> 1659 name_curpos -= shift_bytes;
> 1660 }
> 1661
> 1662 size = name_curpos - (char *)data;
> 1663 fill_note(note, "CORE", NT_FILE, size, data);
> 1664 return 0;
> 1665 }
> 1666
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki
--
- Allen