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 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
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