On Mon, Jul 27, 2026 at 12:48:57PM +0100, Mark Brown wrote: > On Mon, Jul 20, 2026 at 03:38:39PM +0100, Lorenzo Stoakes (ARM) wrote: > > When mapping /dev/zero with MAP_PRIVATE, one ends up with strange VMAs > > originating from Linux's distant past. > > > > These have vma->vm_file set but NULL vma->vm_ops, meaning they satisfy > > vma_is_anonymous() but otherwise resemble a file-backed VMA. > > I'm seeing a test failure in the proc proc-self-map-files-0002 kselftest > which bisects to this change in -next. The test just says: > > # selftests: proc: proc-self-map-files-002 > not ok 11 selftests: proc: proc-self-map-files-002 # exit=1 > > which isn't super informative. Full log at: > > https://lava.sirena.org.uk/scheduler/job/3030495#L13846
Thanks, will investigate! It's likely making some assumptions that no longer apply about MAP_PRIVATE-/dev/zero mappings here. > > bisect log: > > # bad: [c5e32e86ca02b003f86e095d379b38148999293d] Add linux-next specific > files for 20260726 > # good: [692519a077bfb1a66d209e713d2210bb1d9adcaf] Merge branch > 'for-linux-next-fixes' of https://gitlab.freedesktop.org/drm/misc/kernel.git > # good: [ef4f2357df6e9dd6213ce00d01253f3c458d5df0] regmap: clean up > kernel-doc comments > # good: [86e9ba573c353afd1a46816682f4cc3dbabeeb23] irqchip/irq-imgpdc: Remove > unused driver > git bisect start 'c5e32e86ca02b003f86e095d379b38148999293d' > '692519a077bfb1a66d209e713d2210bb1d9adcaf' > 'ef4f2357df6e9dd6213ce00d01253f3c458d5df0' > '86e9ba573c353afd1a46816682f4cc3dbabeeb23' > # test job: [ef4f2357df6e9dd6213ce00d01253f3c458d5df0] > https://lava.sirena.org.uk/scheduler/job/3020719 > # test job: [86e9ba573c353afd1a46816682f4cc3dbabeeb23] > https://lava.sirena.org.uk/scheduler/job/2955047 > # test job: [c5e32e86ca02b003f86e095d379b38148999293d] > https://lava.sirena.org.uk/scheduler/job/3030495 > # bad: [c5e32e86ca02b003f86e095d379b38148999293d] Add linux-next specific > files for 20260726 > git bisect bad c5e32e86ca02b003f86e095d379b38148999293d > # test job: [673a43d4e283e8fc3bee7a874766278427263bc1] > https://lava.sirena.org.uk/scheduler/job/3030777 > # bad: [673a43d4e283e8fc3bee7a874766278427263bc1] Merge branch > 'libcrypto-next' of > https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git > git bisect bad 673a43d4e283e8fc3bee7a874766278427263bc1 > # test job: [5dd91aac4216c19e9eeea6e0c1a04bcb3e43a876] > https://lava.sirena.org.uk/scheduler/job/3031099 > # bad: [5dd91aac4216c19e9eeea6e0c1a04bcb3e43a876] Merge branch > 'xtensa-for-next' of https://github.com/jcmvbkbc/linux-xtensa.git > git bisect bad 5dd91aac4216c19e9eeea6e0c1a04bcb3e43a876 > # test job: [457b365bc545636d75f65067d18afa86f6ced162] > https://lava.sirena.org.uk/scheduler/job/3031248 > # bad: [457b365bc545636d75f65067d18afa86f6ced162] Merge branch 'for-next' of > https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git > git bisect bad 457b365bc545636d75f65067d18afa86f6ced162 > # test job: [a8fa5c7be42a37866fcc315470df3307f0583c47] > https://lava.sirena.org.uk/scheduler/job/3031351 > # good: [a8fa5c7be42a37866fcc315470df3307f0583c47] mm/vma: update > create_init_stack_vma() to use vma_flags_t > git bisect good a8fa5c7be42a37866fcc315470df3307f0583c47 > # test job: [5c9f41c7115f0e16b7e133abca791a4860bee0b6] > https://lava.sirena.org.uk/scheduler/job/3031429 > # bad: [5c9f41c7115f0e16b7e133abca791a4860bee0b6] Merge branch > 'kbuild-for-next' of > https://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux.git > git bisect bad 5c9f41c7115f0e16b7e133abca791a4860bee0b6 > # test job: [c68210527d235e59afa54bc6aba6ecc532488a82] > https://lava.sirena.org.uk/scheduler/job/3031482 > # bad: [c68210527d235e59afa54bc6aba6ecc532488a82] mm: page_alloc: fix > non-movable reclaim storm in defrag_mode > git bisect bad c68210527d235e59afa54bc6aba6ecc532488a82 > # test job: [497078da29fbfe6ae057c020f1e5717ded142471] > https://lava.sirena.org.uk/scheduler/job/3031540 > # good: [497078da29fbfe6ae057c020f1e5717ded142471] mm/huge_memory: fold > split_folio_to_list_to_order() into split_folio_to_order() > git bisect good 497078da29fbfe6ae057c020f1e5717ded142471 > # test job: [2afd297a9a621ad41892bc0a05481110f46ebfc2] > https://lava.sirena.org.uk/scheduler/job/3031619 > # bad: [2afd297a9a621ad41892bc0a05481110f46ebfc2] tools/testing/vma: add test > to assert MAP_PRIVATE-/dev/zero is anon > git bisect bad 2afd297a9a621ad41892bc0a05481110f46ebfc2 > # test job: [a4beb459e21af80c1d8c37b079686753c21932ca] > https://lava.sirena.org.uk/scheduler/job/3031661 > # good: [a4beb459e21af80c1d8c37b079686753c21932ca] mm/vma: introduce VMA > virtual page offset field and add helpers > git bisect good a4beb459e21af80c1d8c37b079686753c21932ca > # test job: [84bd1aceb0233c3de9064028d31a16ecf50070d9] > https://lava.sirena.org.uk/scheduler/job/3031711 > # good: [84bd1aceb0233c3de9064028d31a16ecf50070d9] mm/rmap: track whether the > page VMA mapped walk is anonymous > git bisect good 84bd1aceb0233c3de9064028d31a16ecf50070d9 > # test job: [880b6fe7442df760fe0a726b5f5e568bc6b450b6] > https://lava.sirena.org.uk/scheduler/job/3031752 > # good: [880b6fe7442df760fe0a726b5f5e568bc6b450b6] tools/testing/vma: expand > VMA merge tests to assert virt pgoff > git bisect good 880b6fe7442df760fe0a726b5f5e568bc6b450b6 > # test job: [e2ad1c5a1f0a96a4a0435213b0a5cb963dc501c5] > https://lava.sirena.org.uk/scheduler/job/3031804 > # good: [e2ad1c5a1f0a96a4a0435213b0a5cb963dc501c5] mm/vma: only permit > MAP_PRIVATE /dev/zero to be mapped anonymous > git bisect good e2ad1c5a1f0a96a4a0435213b0a5cb963dc501c5 > # test job: [9f2782812095787d87ee6b742899ae37966ef0f5] > https://lava.sirena.org.uk/scheduler/job/3031854 > # bad: [9f2782812095787d87ee6b742899ae37966ef0f5] mm/vma: make > MAP_PRIVATE-mapped /dev/zero mappings truly anonymous > git bisect bad 9f2782812095787d87ee6b742899ae37966ef0f5 > # first bad commit: [9f2782812095787d87ee6b742899ae37966ef0f5] mm/vma: make > MAP_PRIVATE-mapped /dev/zero mappings truly anonymous Cheers, Lorenzo
