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Sun, 16 Nov 2025 08:46:51 +0000 Date: Sun, 16 Nov 2025 08:46:51 +0000 Message-ID: <868qg6tldw.wl-maz@kernel.org> From: Marc Zyngier To: syzbot Cc: catalin.marinas@arm.com, joey.gouly@arm.com, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, oliver.upton@linux.dev, oupton@kernel.org, suzuki.poulose@arm.com, syzkaller-bugs@googlegroups.com, will@kernel.org, yuzenghui@huawei.com Subject: Re: [syzbot] [kvmarm?] WARNING in kvm_set_vm_id_reg In-Reply-To: <6918cd88.050a0220.1c914e.0044.GAE@google.com> References: <6918cd88.050a0220.1c914e.0044.GAE@google.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: syzbot+c4aef6558d0cd90fe378@syzkaller.appspotmail.com, catalin.marinas@arm.com, joey.gouly@arm.com, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, oliver.upton@linux.dev, oupton@kernel.org, suzuki.poulose@arm.com, syzkaller-bugs@googlegroups.com, will@kernel.org, yuzenghui@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251116_004655_842935_3DDCC2A1 X-CRM114-Status: GOOD ( 12.78 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sat, 15 Nov 2025 18:59:20 +0000, syzbot wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: 7a0892d2836e Merge tag 'pci-v6.18-fixes-5' of git://git.ke.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=12c56884580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=bbf220ce32df0361 > dashboard link: https://syzkaller.appspot.com/bug?extid=c4aef6558d0cd90fe378 > compiler: aarch64-linux-gnu-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 > userspace arch: arm64 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=139c77cd980000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11d6a914580000 > > Downloadable assets: > disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/fa3fbcfdac58/non_bootable_disk-7a0892d2.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/e83411b74df6/vmlinux-7a0892d2.xz > kernel image: https://storage.googleapis.com/syzbot-assets/135caed64c95/Image-7a0892d2.gz.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+c4aef6558d0cd90fe378@syzkaller.appspotmail.com > > ------------[ cut here ]------------ > WARNING: CPU: 1 PID: 3583 at arch/arm64/kvm/sys_regs.c:2353 kvm_set_vm_id_reg+0x60/0xf4 arch/arm64/kvm/sys_regs.c:2348 > Modules linked in: > CPU: 1 UID: 0 PID: 3583 Comm: syz.2.17 Not tainted syzkaller #0 PREEMPT > Hardware name: linux,dummy-virt (DT) > pstate: a1402009 (NzCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) > pc : kvm_set_vm_id_reg+0x60/0xf4 arch/arm64/kvm/sys_regs.c:2353 > lr : kvm_finalize_sys_regs+0x88/0x244 arch/arm64/kvm/sys_regs.c:5616 > sp : ffff800089543ab0 > x29: ffff800089543ab0 x28: f6f00000121c12c0 x27: 0000000000000000 > x26: 0000000000000000 x25: f1f00000085d8000 x24: 0000000000000000 > x23: f1f00000085d8048 x22: 0000000000000000 x21: f9ff800083e0dbd0 > x20: f9ff800083e0d000 x19: f1f00000085d8000 x18: 00000000ffffffff > x17: 0000000000000000 x16: 0000000000000000 x15: ffff800089543a90 > x14: ffff800089543d98 x13: ffff800089543d5a x12: 0000000000000000 > x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000078 > x8 : ffff800089543da8 x7 : f0f0000004469ffc x6 : 0000000000000077 > x5 : f6f00000121c12c0 x4 : 0000000000000001 x3 : f9ff800083e0dd18 > x2 : 1101001020110222 x1 : 0000000000000000 x0 : f9ff800083e0d000 > Call trace: > kvm_set_vm_id_reg+0x60/0xf4 arch/arm64/kvm/sys_regs.c:2348 (P) > kvm_finalize_sys_regs+0x88/0x244 arch/arm64/kvm/sys_regs.c:5616 > kvm_arch_vcpu_run_pid_change+0x8c/0x36c arch/arm64/kvm/arm.c:857 > kvm_vcpu_ioctl+0x7f8/0x878 virt/kvm/kvm_main.c:4464 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:597 [inline] > __se_sys_ioctl fs/ioctl.c:583 [inline] > __arm64_sys_ioctl+0xac/0x104 fs/ioctl.c:583 > __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] > invoke_syscall+0x48/0x110 arch/arm64/kernel/syscall.c:49 > el0_svc_common.constprop.0+0x40/0xe0 arch/arm64/kernel/syscall.c:132 > do_el0_svc+0x1c/0x28 arch/arm64/kernel/syscall.c:151 > el0_svc+0x34/0x10c arch/arm64/kernel/entry-common.c:746 > el0t_64_sync_handler+0xa0/0xe4 arch/arm64/kernel/entry-common.c:765 > el0t_64_sync+0x1a4/0x1a8 arch/arm64/kernel/entry.S:596 > ---[ end trace 0000000000000000 ]--- #syz fix KVM: arm64: Finalize ID registers only once per VM M. -- Without deviation from the norm, progress is not possible.