Messages in this thread | | | Date | Mon, 18 Sep 2023 09:41:07 +0200 | Subject | Re: [syzbot] [mm?] WARNING in page_add_anon_rmap | From | David Hildenbrand <> |
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On 18.09.23 05:57, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 98897dc735cf Add linux-next specific files for 20230914 > git tree: linux-next > console+strace: https://syzkaller.appspot.com/x/log.txt?x=1214a152680000 > kernel config: https://syzkaller.appspot.com/x/.config?x=1502c503717ada5c > dashboard link: https://syzkaller.appspot.com/bug?extid=6e4f59235036c3c2e296 > compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15869ea0680000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15f1b952680000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/00e4c0af5a8a/disk-98897dc7.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/7b54a00eee56/vmlinux-98897dc7.xz > kernel image: https://storage.googleapis.com/syzbot-assets/100094353b8e/bzImage-98897dc7.xz > > The issue was bisected to: > > commit b8575fa4abaa1dee1a61f1f27a86a02757310a7e > Author: David Hildenbrand <david@redhat.com> > Date: Wed Sep 13 12:51:12 2023 +0000 > > mm/rmap: simplify PageAnonExclusive sanity checks when adding anon rmap >
Right, when PTE-mapping a THP we temporarily have an entire mapping and a sub-page mapping. It would even be clearer when passing RMAP_EXCLUSIVE from __split_huge_pmd_locked(), then setting it manually. But that's a different story; lets' fixup that sanity check first.
-- Cheers,
David / dhildenb
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