* [davidhildenbrand:b4/uffd_marker_loss 3/4] mm/userfaultfd.c:236 mfill_get_vma() warn: bitwise AND condition is false here
@ 2026-11-06 21:06 kernel test robot
0 siblings, 0 replies; only message in thread
From: kernel test robot @ 2026-11-06 21:06 UTC (permalink / raw)
To: oe-kbuild; +Cc: lkp, Dan Carpenter
Unfiltered warning: this smatch report is sent as-is and has not been
reviewed for false positives, so please treat it with due skepticism.
BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
TO: "David Hildenbrand (Arm)" <david@kernel.org>
tree: https://github.com/davidhildenbrand/linux b4/uffd_marker_loss
head: f873c4d8fea81d69055efcca51bad3c0dd0a4b04
commit: 4fbc77f3f8866a6ce733498aadfb4504febd08e6 [3/4] mm/userfaultfd: preserve poison markers after unregistering
:::::: branch date: 6 hours ago
:::::: commit date: 9 hours ago
config: microblaze-randconfig-2200-20261106 (https://download.01.org/0day-ci/archive/20261106/202611062242.DHsJsdWZ-lkp@intel.com/config)
compiler: microblaze-linux-gcc (GCC) 14.4.0
smatch: v0.5.0-9187-g5189e3fb
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@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202611062242.DHsJsdWZ-lkp@intel.com/
smatch warnings:
mm/userfaultfd.c:236 mfill_get_vma() warn: bitwise AND condition is false here
vim +236 mm/userfaultfd.c
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 194)
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 195) static int mfill_get_vma(struct mfill_state *state)
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 196) {
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 197) struct userfaultfd_ctx *ctx = state->ctx;
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 198) uffd_flags_t flags = state->flags;
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 199) struct vm_area_struct *dst_vma;
dfc4d771820a17 Mike Rapoport (Microsoft 2026-04-02 200) const struct vm_uffd_ops *ops;
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 201) int err;
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 202)
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 203) /*
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 204) * Make sure the vma is not shared, that the dst range is
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 205) * both valid and fully within a single existing vma.
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 206) */
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 207) dst_vma = uffd_mfill_lock(ctx->mm, state->dst_start, state->len);
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 208) if (IS_ERR(dst_vma))
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 209) return PTR_ERR(dst_vma);
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 210)
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 211) /*
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 212) * If memory mappings are changing because of non-cooperative
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 213) * operation (e.g. mremap) running in parallel, bail out and
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 214) * request the user to retry later
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 215) */
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 216) down_read(&ctx->map_changing_lock);
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 217) state->vma = dst_vma;
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 218) err = -EAGAIN;
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 219) if (atomic_read(&ctx->mmap_changing))
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 220) goto out_unlock;
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 221)
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 222) err = -EINVAL;
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 223)
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 224) /*
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 225) * shmem_zero_setup is invoked in mmap for MAP_ANONYMOUS|MAP_SHARED but
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 226) * it will overwrite vm_ops, so vma_is_anonymous must return false.
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 227) */
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 228) if (WARN_ON_ONCE(vma_is_anonymous(dst_vma) &&
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 229) dst_vma->vm_flags & VM_SHARED))
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 230) goto out_unlock;
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 231)
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 232) /*
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 233) * validate 'mode' now that we know the dst_vma: don't allow
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 234) * a wrprotect copy if the userfaultfd didn't register as WP.
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 235) */
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 @236) if ((flags & MFILL_ATOMIC_WP) && !(dst_vma->vm_flags & VM_UFFD_WP))
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 237) goto out_unlock;
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 238)
c911e7ebebf58c Lorenzo Stoakes (ARM 2026-10-13 239) if (vma_is_hugetlb(dst_vma))
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 240) return 0;
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 241)
dfc4d771820a17 Mike Rapoport (Microsoft 2026-04-02 242) ops = vma_uffd_ops(dst_vma);
dfc4d771820a17 Mike Rapoport (Microsoft 2026-04-02 243) if (!ops)
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 244) goto out_unlock;
dfc4d771820a17 Mike Rapoport (Microsoft 2026-04-02 245)
dfc4d771820a17 Mike Rapoport (Microsoft 2026-04-02 246) if (uffd_flags_mode_is(flags, MFILL_ATOMIC_CONTINUE) &&
dfc4d771820a17 Mike Rapoport (Microsoft 2026-04-02 247) !ops->get_folio_noalloc)
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 248) goto out_unlock;
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 249)
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 250) return 0;
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 251)
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 252) out_unlock:
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 253) mfill_put_vma(state);
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 254) return err;
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 255) }
b8c03b7f455821 Mike Rapoport (Microsoft 2026-04-02 256)
:::::: The code at line 236 was first introduced by commit
:::::: b8c03b7f4558219ca09693b5fa4f5e068041d2c2 userfaultfd: introduce mfill_get_vma() and mfill_put_vma()
:::::: TO: Mike Rapoport (Microsoft) <rppt@kernel.org>
:::::: CC: Andrew Morton <akpm@linux-foundation.org>
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
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2026-11-06 21:06 [davidhildenbrand:b4/uffd_marker_loss 3/4] mm/userfaultfd.c:236 mfill_get_vma() warn: bitwise AND condition is false here kernel test robot
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