From: Mike Kravetz <mike.kravetz@oracle.com>
To: syzbot <syzbot+f0b97304ef90f0d0b1dc@syzkaller.appspotmail.com>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, llvm@lists.linux.dev, nathan@kernel.org,
ndesaulniers@google.com, songmuchun@bytedance.com,
syzkaller-bugs@googlegroups.com, trix@redhat.com,
David Hildenbrand <david@redhat.com>
Subject: Re: [syzbot] WARNING in hugetlb_wp
Date: Sat, 29 Oct 2022 17:35:13 -0700 [thread overview]
Message-ID: <Y13GwSF8e6vMyYyY@monkey> (raw)
In-Reply-To: <000000000000ed009f05ec257623@google.com>
On 10/28/22 22:15, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 247f34f7b803 Linux 6.1-rc2
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=14a9efd2880000
> kernel config: https://syzkaller.appspot.com/x/.config?x=a66c6c673fb555e8
> dashboard link: https://syzkaller.appspot.com/bug?extid=f0b97304ef90f0d0b1dc
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=112217b4880000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=105f4616880000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/de212436b09b/disk-247f34f7.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/63c4feda220f/vmlinux-247f34f7.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+f0b97304ef90f0d0b1dc@syzkaller.appspotmail.com
>
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 3612 at mm/hugetlb.c:5313 hugetlb_wp+0x20a/0x1af0 mm/hugetlb.c:5313
This warning was added with commit 1d8d14641fd94 ("mm/hugetlb: support write-faults
in shared mappings"). It is there 'by design' as this this specific
type of write fault is not supported.
/*
* hugetlb does not support FOLL_FORCE-style write faults that keep the
* PTE mapped R/O such as maybe_mkwrite() would do.
*/
if (WARN_ON_ONCE(!unshare && !(vma->vm_flags & VM_WRITE)))
return VM_FAULT_SIGSEGV;
If there is an actual use case for this support, we can look at adding it.
--
Mike Kravetz
next prev parent reply other threads:[~2022-10-30 0:35 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-29 5:15 [syzbot] WARNING in hugetlb_wp syzbot
2022-10-30 0:35 ` Mike Kravetz [this message]
2022-10-30 8:53 ` David Hildenbrand
2022-10-31 14:13 ` David Hildenbrand
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