Re: [PATCH] lib/buildid: Handle memfd_secret() files in build_id_parse()

[Sasha Levin <sashal@kernel.org>]

[ Sasha's backport helper bot ]

Hi,

Summary of potential issues:
❌ Build failures detected
⚠️ Found matching upstream commit but patch is missing proper reference to it

Found matching upstream commit: 5ac9b4e935dfc6af41eee2ddc21deb5c36507a9f

WARNING: Author mismatch between patch and found commit:
Backport author: Chen Linxuan<chenlinxuan@deepin.org>
Commit author: Andrii Nakryiko<andrii@kernel.org>

Status in newer kernel trees:
6.6.y | Not found

Note: The patch differs from the upstream commit:
---
Failed to apply patch cleanly.
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.13.y       |  Failed     |  N/A       |
| stable/linux-6.12.y       |  Failed     |  N/A       |
| stable/linux-6.6.y        |  Success    |  Failed    |
| stable/linux-6.1.y        |  Success    |  Success   |
| stable/linux-5.15.y       |  Success    |  Success   |
| stable/linux-5.10.y       |  Failed     |  N/A       |
| stable/linux-5.4.y        |  Failed     |  N/A       |

Build Errors:
Patch failed to apply on stable/linux-6.13.y. Reject:

diff a/lib/buildid.c b/lib/buildid.c	(rejected hunks)
@@ -157,6 +157,12 @@ int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id,
 	if (!vma->vm_file)
 		return -EINVAL;
 
+#ifdef CONFIG_SECRETMEM
+	/* reject secretmem folios created with memfd_secret() */
+	if (vma->vm_file->f_mapping->a_ops == &secretmem_aops)
+		return -EFAULT;
+#endif
+
 	page = find_get_page(vma->vm_file->f_mapping, 0);
 	if (!page)
 		return -EFAULT;	/* page not mapped */
Patch failed to apply on stable/linux-6.12.y. Reject:

diff a/lib/buildid.c b/lib/buildid.c	(rejected hunks)
@@ -157,6 +157,12 @@ int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id,
 	if (!vma->vm_file)
 		return -EINVAL;
 
+#ifdef CONFIG_SECRETMEM
+	/* reject secretmem folios created with memfd_secret() */
+	if (vma->vm_file->f_mapping->a_ops == &secretmem_aops)
+		return -EFAULT;
+#endif
+
 	page = find_get_page(vma->vm_file->f_mapping, 0);
 	if (!page)
 		return -EFAULT;	/* page not mapped */
Build error for stable/linux-6.6.y:
    lib/buildid.c: In function 'build_id_parse':
    lib/buildid.c:162:48: error: 'secretmem_aops' undeclared (first use in this function)
      162 |         if (vma->vm_file->f_mapping->a_ops == &secretmem_aops)
          |                                                ^~~~~~~~~~~~~~
    lib/buildid.c:162:48: note: each undeclared identifier is reported only once for each function it appears in
    make[3]: *** [scripts/Makefile.build:243: lib/buildid.o] Error 1
    lib/test_dhry.o: warning: objtool: dhry() falls through to next function dhry_run_set.cold()
    make[3]: Target 'lib/' not remade because of errors.
    make[2]: *** [scripts/Makefile.build:480: lib] Error 2
    make[2]: Target './' not remade because of errors.
    make[1]: *** [/home/sasha/build/linus-next/Makefile:1916: .] Error 2
    make[1]: Target '__all' not remade because of errors.
    make: *** [Makefile:234: __sub-make] Error 2
    make: Target '__all' not remade because of errors.

Patch failed to apply on stable/linux-5.10.y but no reject information available.
Patch failed to apply on stable/linux-5.4.y but no reject information available.