On Mon, 2024-03-18 at 09:25 -0700, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 277100b3d5fe Merge tag 'block-6.9-20240315' of git://git.k.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=17c96aa5180000 > kernel config: https://syzkaller.appspot.com/x/.config?x=1c6662240382da2 > dashboard link: https://syzkaller.appspot.com/bug?extid=106a4f72b0474e1d1b33 > 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=14358231180000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=110ed231180000 > > Downloadable assets: > disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-277100b3.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/6872e049b27c/vmlinux-277100b3.xz > kernel image: https://storage.googleapis.com/syzbot-assets/68ec7230df0f/bzImage-277100b3.xz static int __kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsigned long uhva, unsigned long len) { unsigned long page_offset; bool unmap_old = false; unsigned long old_uhva; kvm_pfn_t old_pfn; bool hva_change = false; void *old_khva; int ret; /* Either gpa or uhva must be valid, but not both */ if (WARN_ON_ONCE(kvm_is_error_gpa(gpa) == kvm_is_error_hva(uhva))) return -EINVAL; Hm, that comment doesn't match the code. It says "not both", but the code also catches the "neither" case. I think the gpa is in %rbx and uhva is in %r12, so this is indeed the 'neither' case. Is it expected that we can end up with a cache marked active, but with the address not valid? Maybe through a race condition with deactive? or more likely than that? Paul, we should probably add ourselves to MAINTAINERS for pfncache.c ffffffff810c8650 <__kvm_gpc_refresh>: ffffffff810c8650: 41 57 push %r15 ffffffff810c8652: 41 56 push %r14 ffffffff810c8654: 49 89 ce mov %rcx,%r14 ffffffff810c8657: 41 55 push %r13 ffffffff810c8659: 49 bd ff ff ff ff 7f movabs $0xffff887fffffffff,%r13 ffffffff810c8660: 88 ff ff ffffffff810c8663: 41 54 push %r12 ffffffff810c8665: 49 89 d4 mov %rdx,%r12 ffffffff810c8668: 55 push %rbp ffffffff810c8669: 48 89 fd mov %rdi,%rbp ffffffff810c866c: 53 push %rbx ffffffff810c866d: 48 89 f3 mov %rsi,%rbx ffffffff810c8670: 48 83 ec 68 sub $0x68,%rsp ffffffff810c8674: e8 17 9b 80 00 call ffffffff818d2190 <__sanitizer_cov_trace_pc> ffffffff810c8679: 48 89 de mov %rbx,%rsi ffffffff810c867c: 48 c7 c7 ff ff ff ff mov $0xffffffffffffffff,%rdi ffffffff810c8683: e8 18 96 80 00 call ffffffff818d1ca0 <__sanitizer_cov_trace_const_cmp8> ffffffff810c8688: 48 83 fb ff cmp $0xffffffffffffffff,%rbx ffffffff810c868c: 4c 89 ef mov %r13,%rdi ffffffff810c868f: 4c 89 e6 mov %r12,%rsi ffffffff810c8692: 41 0f 94 c7 sete %r15b ffffffff810c8696: e8 05 96 80 00 call ffffffff818d1ca0 <__sanitizer_cov_trace_const_cmp8> ffffffff810c869b: 4d 39 e5 cmp %r12,%r13 ffffffff810c869e: 44 89 ff mov %r15d,%edi ffffffff810c86a1: 41 0f 92 c5 setb %r13b ffffffff810c86a5: 44 89 ee mov %r13d,%esi ffffffff810c86a8: e8 a3 94 80 00 call ffffffff818d1b50 <__sanitizer_cov_trace_cmp1> ffffffff810c86ad: 45 38 ef cmp %r13b,%r15b ffffffff810c86b0: 0f 84 76 15 00 00 je ffffffff810c9c2c <__kvm_gpc_refresh+0x15dc> > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+106a4f72b0474e1d1b33@xxxxxxxxxxxxxxxxxxxxxxxxx > > ------------[ cut here ]------------ > WARNING: CPU: 1 PID: 5192 at arch/x86/kvm/../../../virt/kvm/pfncache.c:247 __kvm_gpc_refresh+0x15e2/0x2200 arch/x86/kvm/../../../virt/kvm/pfncache.c:247 > Modules linked in: > CPU: 1 PID: 5192 Comm: syz-executor422 Not tainted 6.8.0-syzkaller-11063-g277100b3d5fe #0 > Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 > RIP: 0010:__kvm_gpc_refresh+0x15e2/0x2200 arch/x86/kvm/../../../virt/kvm/pfncache.c:247 > Code: 48 c7 c2 a0 5e 02 8b be 5d 03 00 00 48 c7 c7 60 5e 02 8b c6 05 bd 89 7c 0e 01 e8 a9 23 5e 00 e9 31 fb ff ff e8 5f 85 80 00 90 <0f> 0b 90 e9 69 f7 ff ff e8 51 85 80 00 48 8b 54 24 40 48 b8 00 00 > RSP: 0018:ffffc9000317f940 EFLAGS: 00010293 > RAX: 0000000000000000 RBX: ffffffffffffffff RCX: ffffffff810c86ad > RDX: ffff888022360000 RSI: ffffffff810c9c31 RDI: 0000000000000000 > RBP: ffff88802f2c0948 R08: 0000000000000000 R09: 0000000000000001 > R10: 0000000000000001 R11: 0000000000000002 R12: ffff888000000000 > R13: ffff887fffffff01 R14: 0000000000000020 R15: 0000000000000001 > FS: 000055555b2d9380(0000) GS:ffff88806b300000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000000000 CR3: 000000002fa8a000 CR4: 0000000000352ef0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > <TASK> > kvm_gpc_refresh+0x7d/0xe0 arch/x86/kvm/../../../virt/kvm/pfncache.c:364 > kvm_setup_guest_pvclock+0x5b/0x6f0 arch/x86/kvm/x86.c:3174 > kvm_guest_time_update+0x935/0xeb0 arch/x86/kvm/x86.c:3313 > vcpu_enter_guest arch/x86/kvm/x86.c:10769 [inline] > vcpu_run+0x1993/0x4e60 arch/x86/kvm/x86.c:11211 > kvm_arch_vcpu_ioctl_run+0x42e/0x1680 arch/x86/kvm/x86.c:11437 > kvm_vcpu_ioctl+0x5a1/0x1060 arch/x86/kvm/../../../virt/kvm/kvm_main.c:4464 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:904 [inline] > __se_sys_ioctl fs/ioctl.c:890 [inline] > __x64_sys_ioctl+0x193/0x220 fs/ioctl.c:890 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x6d/0x75 > RIP: 0033:0x7fb4618fd069 > Code: 48 83 c4 28 c3 e8 d7 19 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:00007ffd71e140e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 00007fb4618fd069 RCX: 00007fb4618fd069 > RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000006 > RBP: 00007fb46194a07e R08: 00007ffd71e14218 R09: 00007ffd71e14218 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd71e14150 > R13: 00007ffd71e14130 R14: 00007ffd71e14120 R15: 00007fb46194a012 > </TASK> > > > --- > 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. > > 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 >
Attachment:
smime.p7s
Description: S/MIME cryptographic signature
