From: Suren Baghdasaryan <surenb@google.com>
To: Dan Carpenter <dan.carpenter@linaro.org>
Cc: oe-kbuild@lists.linux.dev, lkp@intel.com,
oe-kbuild-all@lists.linux.dev,
Linux Memory Management List <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [linux-next:master 2565/2825] mm/userfaultfd.c:983 move_zeropage_pte() warn: inconsistent returns 'dst_ptl'.
Date: Tue, 30 Jan 2024 18:37:14 -0800 [thread overview]
Message-ID: <CAJuCfpHyTjB+HKEZn+ddkQOCdHZJMgG4bYOfJM=NOBcGBkYeew@mail.gmail.com> (raw)
In-Reply-To: <1a42e4fc-54a0-49f1-94ba-f075e0ef29a8@moroto.mountain>
On Mon, Jan 29, 2024 at 9:13 PM Dan Carpenter <dan.carpenter@linaro.org> wrote:
>
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head: 596764183be8ebb13352b281a442a1f1151c9b06
> commit: ea4df6a5ea81105879ca5549555e231c4596fbc4 [2565/2825] userfaultfd: handle zeropage moves by UFFDIO_MOVE
> config: x86_64-randconfig-161-20240129 (https://download.01.org/0day-ci/archive/20240130/202401300107.U8iMAkTl-lkp@intel.com/config)
> compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0
>
> 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 <dan.carpenter@linaro.org>
> | Closes: https://lore.kernel.org/r/202401300107.U8iMAkTl-lkp@intel.com/
>
> smatch warnings:
> mm/userfaultfd.c:983 move_zeropage_pte() warn: inconsistent returns 'dst_ptl'.
>
> vim +/dst_ptl +983 mm/userfaultfd.c
>
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 962 static int move_zeropage_pte(struct mm_struct *mm,
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 963 struct vm_area_struct *dst_vma,
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 964 struct vm_area_struct *src_vma,
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 965 unsigned long dst_addr, unsigned long src_addr,
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 966 pte_t *dst_pte, pte_t *src_pte,
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 967 pte_t orig_dst_pte, pte_t orig_src_pte,
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 968 spinlock_t *dst_ptl, spinlock_t *src_ptl)
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 969 {
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 970 pte_t zero_pte;
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 971
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 972 double_pt_lock(dst_ptl, src_ptl);
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 973 if (!pte_same(ptep_get(src_pte), orig_src_pte) ||
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 974 !pte_same(ptep_get(dst_pte), orig_dst_pte))
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 975 return -EAGAIN;
>
> double_pt_unlock(dst_ptl, src_ptl) before returning?
Thanks for reporting and sorry for the delay!
Yes, this is definitely a bug. I'll post a fix tomorrow morning.
Thanks,
Suren.
>
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 976
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 977 zero_pte = pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr),
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 978 dst_vma->vm_page_prot));
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 979 ptep_clear_flush(src_vma, src_addr, src_pte);
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 980 set_pte_at(mm, dst_addr, dst_pte, zero_pte);
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 981 double_pt_unlock(dst_ptl, src_ptl);
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 982
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 @983 return 0;
> ea4df6a5ea8110 Suren Baghdasaryan 2024-01-24 984 }
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki
>
next prev parent reply other threads:[~2024-01-31 2:37 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-30 5:13 Dan Carpenter
2024-01-31 2:37 ` Suren Baghdasaryan [this message]
2024-01-31 18:03 ` Suren Baghdasaryan
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