On Thu, Jan 11, 2024 at 8:44 AM Suren Baghdasaryan <surenb@xxxxxxxxxx> wrote: > > On Thu, Jan 11, 2024 at 8:40 AM Suren Baghdasaryan <surenb@xxxxxxxxxx> wrote: > > > > On Thu, Jan 11, 2024 at 8:25 AM syzbot > > <syzbot+705209281e36404998f6@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > > > > > Hello, > > > > > > syzbot found the following issue on: > > > > > > HEAD commit: e2425464bc87 Add linux-next specific files for 20240105 > > > git tree: linux-next > > > console+strace: https://syzkaller.appspot.com/x/log.txt?x=14941cdee80000 > > > kernel config: https://syzkaller.appspot.com/x/.config?x=4056b9349f3da8c9 > > > dashboard link: https://syzkaller.appspot.com/bug?extid=705209281e36404998f6 > > > 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=125d0a09e80000 > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15bc7331e80000 > > > > > > Downloadable assets: > > > disk image: https://storage.googleapis.com/syzbot-assets/2f738185e2cf/disk-e2425464.raw.xz > > > vmlinux: https://storage.googleapis.com/syzbot-assets/b248fcf4ea46/vmlinux-e2425464.xz > > > kernel image: https://storage.googleapis.com/syzbot-assets/a9945c8223f4/bzImage-e2425464.xz > > > > > > The issue was bisected to: > > > > > > commit adef440691bab824e39c1b17382322d195e1fab0 > > > Author: Andrea Arcangeli <aarcange@xxxxxxxxxx> > > > Date: Wed Dec 6 10:36:56 2023 +0000 > > > > > > userfaultfd: UFFDIO_MOVE uABI > > > > > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=11cb6ea9e80000 > > > final oops: https://syzkaller.appspot.com/x/report.txt?x=13cb6ea9e80000 > > > console output: https://syzkaller.appspot.com/x/log.txt?x=15cb6ea9e80000 > > > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > > Reported-by: syzbot+705209281e36404998f6@xxxxxxxxxxxxxxxxxxxxxxxxx > > > Fixes: adef440691ba ("userfaultfd: UFFDIO_MOVE uABI") > > > > > > do_one_initcall+0x128/0x680 init/main.c:1237 > > > do_initcall_level init/main.c:1299 [inline] > > > do_initcalls init/main.c:1315 [inline] > > > do_basic_setup init/main.c:1334 [inline] > > > kernel_init_freeable+0x692/0xc30 init/main.c:1552 > > > kernel_init+0x1c/0x2a0 init/main.c:1442 > > > ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 > > > ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 > > > ------------[ cut here ]------------ > > > kernel BUG at include/linux/page-flags.h:1035! > > > invalid opcode: 0000 [#1] PREEMPT SMP KASAN > > > CPU: 0 PID: 5068 Comm: syz-executor191 Not tainted 6.7.0-rc8-next-20240105-syzkaller #0 > > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 > > > RIP: 0010:PageAnonExclusive include/linux/page-flags.h:1035 [inline] > > > > From a quick look, I think the new ioctl is being used against a > > file-backed page and that's why PageAnonExclusive() throws this error. > > I'll confirm if this is indeed the case and will add checks for that > > case. Thanks! > > Hmm. Looking at the reproducer it does not look like a file-backed > memory... Anyways, I'm on it. Looks like the test is trying to move the huge_zero_page. Wonder how we should handle this. Just fail or do something else? Adding David and Peter for feedback. > > > > > > RIP: 0010:move_pages+0x1697/0x3d40 mm/userfaultfd.c:1402 > > > Code: 00 00 48 c1 e8 0c 48 21 d0 48 c1 e0 06 48 01 c3 e9 b6 f7 ff ff e8 79 c6 9c ff 48 c7 c6 e0 7e dc 8a 48 89 df e8 0a 20 dc ff 90 <0f> 0b e8 62 c6 9c ff 48 89 da b8 ff ff 37 00 48 c1 ea 03 48 c1 e0 > > > RSP: 0018:ffffc90003aefa98 EFLAGS: 00010293 > > > RAX: 0000000000000000 RBX: ffffea0001e40000 RCX: ffffffff81687599 > > > RDX: ffff88802a155940 RSI: ffffffff81eb5d46 RDI: 0000000000000000 > > > RBP: ffff88802abab810 R08: 0000000000000000 R09: fffffbfff1e75fda > > > R10: ffffffff8f3afed7 R11: 0000000000000001 R12: 0000000000000000 > > > R13: 0000000000000000 R14: 0000000020518000 R15: 0000000000000000 > > > FS: 00005555562cf380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > > CR2: 00000000204f8000 CR3: 000000006a725000 CR4: 00000000003506f0 > > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > Call Trace: > > > <TASK> > > > userfaultfd_move fs/userfaultfd.c:2047 [inline] > > > userfaultfd_ioctl+0x683/0x6420 fs/userfaultfd.c:2169 > > > vfs_ioctl fs/ioctl.c:51 [inline] > > > __do_sys_ioctl fs/ioctl.c:871 [inline] > > > __se_sys_ioctl fs/ioctl.c:857 [inline] > > > __x64_sys_ioctl+0x18f/0x210 fs/ioctl.c:857 > > > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > > > do_syscall_64+0xd0/0x250 arch/x86/entry/common.c:83 > > > entry_SYSCALL_64_after_hwframe+0x62/0x6a > > > RIP: 0033:0x7f4bada9b3e9 > > > Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 > > > RSP: 002b:00007fff2c1d6998 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > > > RAX: ffffffffffffffda RBX: 00007fff2c1d6b68 RCX: 00007f4bada9b3e9 > > > RDX: 00000000200000c0 RSI: 00000000c028aa05 RDI: 0000000000000003 > > > RBP: 00007f4badb0e610 R08: 00007fff2c1d6b68 R09: 00007fff2c1d6b68 > > > R10: 00007fff2c1d6b68 R11: 0000000000000246 R12: 0000000000000001 > > > R13: 00007fff2c1d6b58 R14: 0000000000000001 R15: 0000000000000001 > > > </TASK> > > > Modules linked in: > > > ---[ end trace 0000000000000000 ]--- > > > RIP: 0010:PageAnonExclusive include/linux/page-flags.h:1035 [inline] > > > RIP: 0010:move_pages+0x1697/0x3d40 mm/userfaultfd.c:1402 > > > Code: 00 00 48 c1 e8 0c 48 21 d0 48 c1 e0 06 48 01 c3 e9 b6 f7 ff ff e8 79 c6 9c ff 48 c7 c6 e0 7e dc 8a 48 89 df e8 0a 20 dc ff 90 <0f> 0b e8 62 c6 9c ff 48 89 da b8 ff ff 37 00 48 c1 ea 03 48 c1 e0 > > > RSP: 0018:ffffc90003aefa98 EFLAGS: 00010293 > > > RAX: 0000000000000000 RBX: ffffea0001e40000 RCX: ffffffff81687599 > > > RDX: ffff88802a155940 RSI: ffffffff81eb5d46 RDI: 0000000000000000 > > > RBP: ffff88802abab810 R08: 0000000000000000 R09: fffffbfff1e75fda > > > R10: ffffffff8f3afed7 R11: 0000000000000001 R12: 0000000000000000 > > > R13: 0000000000000000 R14: 0000000020518000 R15: 0000000000000000 > > > FS: 00005555562cf380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > > CR2: 00000000204f8000 CR3: 000000006a725000 CR4: 00000000003506f0 > > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > > > > > > > --- > > > This report is generated by a bot. It may contain errors. > > > See https://goo.gl/tpsmEJ for more information about syzbot. > > > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > > > > > syzbot will keep track of this issue. See: > > > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > > > > > > If the report is already addressed, let syzbot know by replying with: > > > #syz fix: exact-commit-title > > > > > > If you want syzbot to run the reproducer, reply with: > > > #syz test: git://repo/address.git branch-or-commit-hash > > > If you attach or paste a git patch, syzbot will apply it before testing. > > > > > > If you want to overwrite report's subsystems, reply with: > > > #syz set subsystems: new-subsystem > > > (See the list of subsystem names on the web dashboard) > > > > > > If the report is a duplicate of another one, reply with: > > > #syz dup: exact-subject-of-another-report > > > > > > If you want to undo deduplication, reply with: > > > #syz undup
