Messages in this thread | | | From | Thomas Gleixner <> | Subject | Re: [syzbot] [mm?] BUG: unable to handle kernel paging request in copy_from_kernel_nofault | Date | Tue, 21 Nov 2023 18:13:36 +0100 |
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On Sun, Nov 19 2023 at 09:53, syzbot wrote: > HEAD commit: 1fda5bb66ad8 bpf: Do not allocate percpu memory at init st.. > git tree: bpf > console+strace: https://syzkaller.appspot.com/x/log.txt?x=12d99420e80000 > kernel config: https://syzkaller.appspot.com/x/.config?x=2ae0ccd6bfde5eb0 > dashboard link: https://syzkaller.appspot.com/bug?extid=72aa0161922eba61b50e > 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=16dff22f680000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1027dc70e80000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/3e24d257ce8d/disk-1fda5bb6.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/eaa9caffb0e4/vmlinux-1fda5bb6.xz > kernel image: https://storage.googleapis.com/syzbot-assets/16182bbed726/bzImage-1fda5bb6.xz > > The issue was bisected to: > > commit ca247283781d754216395a41c5e8be8ec79a5f1c > Author: Andy Lutomirski <luto@kernel.org> > Date: Wed Feb 10 02:33:45 2021 +0000 > > x86/fault: Don't run fixups for SMAP violations
Reverting that makes the Ooops go away, but wrongly so.
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=103d92db680000 > final oops: https://syzkaller.appspot.com/x/report.txt?x=123d92db680000 > console output: https://syzkaller.appspot.com/x/log.txt?x=143d92db680000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+72aa0161922eba61b50e@syzkaller.appspotmail.com > Fixes: ca247283781d ("x86/fault: Don't run fixups for SMAP violations") > > BUG: unable to handle page fault for address: ffffffffff600000
This is VSYSCALL_ADDR.
So the real question is why the BPF program tries to copy from the VSYSCALL page, which is not mapped.
Thanks,
tglx
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