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AKwUvBySwd4y3yqI76OJ/0+Xm+3zcVdjkPeKm4Fk3BemFW/1h4j1Lqgo/xWs8YbfergyCC/EzAvXMYQZ7cZY6CY=@vger.kernel.org X-Gm-Message-State: AFuF++l/vav+gTKXrHg/F+aPM96iybF9WFKcC27JaurCmtFPJMwmhb84 SJ4AaZLK1ALafqJe7OF17mZThnDcV9Hkjm8tq9s1QjvA5xXRj8C13Pk/BhpJFr0dToR4TFD31oz VjGGvtw== X-Received: from pjc7.prod.google.com ([2002:a17:90b:2f47:b0:38f:dec2:2549]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:1f91:b0:398:9bd5:4910 with SMTP id 98e67ed59e1d1-39dbc7205aemr573686a91.23.1789167761268; Fri, 11 Sep 2026 16:02:41 -0700 (PDT) Date: Fri, 11 Sep 2026 16:02:40 -0700 In-Reply-To: <6aa42297.f2639fcc.29487d.002f.GAE@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <6aa42297.f2639fcc.29487d.002f.GAE@google.com> Message-ID: Subject: Re: [syzbot] [kvm?] INFO: task hung in kvm_gmem_release (2) From: Sean Christopherson To: syzbot Cc: david@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, pbonzini@redhat.com, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="us-ascii" On Fri, Sep 11, 2026, syzbot wrote: > syzbot found the following issue on: > > HEAD commit: 50d05c7c76c9 Merge tag 'landlock-7.3-rc3' of git://git.ker.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=13db5ef9580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=5e4e3a0e188a497e > dashboard link: https://syzkaller.appspot.com/bug?extid=ab6273c58262b9de56d9 > compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 > userspace arch: i386 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=143121f9580000 The reproducer is "only" setting memory attributes on a 16MiB range. I was expecting a much, much larger range. I suspect this one may be due to a problem with the underlying GCE host? Though it did spit out a reproducer... > CPU: 1 UID: 0 PID: 6083 Comm: syz.4.24 Not tainted syzkaller #0 PREEMPT(full) > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 > RIP: 0010:__this_cpu_preempt_check+0x0/0x20 lib/smp_processor_id.c:63 > Code: f5 48 8b 74 24 20 48 c7 c7 00 9b 6d 8c e8 88 ac 42 f5 e8 23 ab 4d f5 eb ae 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 89 fe 48 c7 c7 80 9a 6d 8c e9 0d ff ff ff cc cc cc > RSP: 0018:ffffc90003d27460 EFLAGS: 00000046 > RAX: 0000000000000001 RBX: 0000000000000001 RCX: 8000000000000001 > RDX: 0000000000000000 RSI: ffff88807ea4a3d0 RDI: ffffffff8e6fe7fc > RBP: 00000000ffffffff R08: ffffc90003d2755f R09: 0000000000000000 > R10: ffffc90003d27548 R11: fffff520007a4eac R12: 0000000000000246 > R13: ffff8880314c5dc0 R14: ffff88807ea4a3d0 R15: 0000000000000001 > FS: 0000000000000000(0000) GS:ffff888124dd2000(0063) knlGS:00000000f6834b40 > CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 > CR2: 00000000f71e8c10 CR3: 0000000073d5a000 CR4: 00000000003526f0 > Call Trace: > > lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline] > lock_is_held_type+0xdf/0x150 kernel/locking/lockdep.c:6017 > lock_is_held include/linux/lockdep.h:249 [inline] > xa_entry include/linux/xarray.h:1227 [inline] > xas_descend lib/xarray.c:208 [inline] > xas_load+0x198/0x5a0 lib/xarray.c:246 > __xa_cmpxchg_raw lib/xarray.c:1783 [inline] > __xa_cmpxchg+0xc3/0x1f0 lib/xarray.c:1769 > xa_cmpxchg include/linux/xarray.h:699 [inline] > xa_reserve include/linux/xarray.h:1088 [inline] > kvm_vm_set_mem_attributes virt/kvm/kvm_main.c:2577 [inline] > kvm_vm_ioctl_set_mem_attributes+0x429/0x1600 virt/kvm/kvm_main.c:2625 > kvm_vm_ioctl+0xb33/0xd30 virt/kvm/kvm_main.c:5356 > kvm_vm_compat_ioctl+0x2b1/0x3a0 virt/kvm/kvm_main.c:5480 > __do_compat_sys_ioctl fs/ioctl.c:695 [inline] > __se_compat_sys_ioctl fs/ioctl.c:638 [inline] > __ia32_compat_sys_ioctl+0x5ea/0x950 fs/ioctl.c:638 > do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline] > __do_fast_syscall_32+0x27a/0x6a0 arch/x86/entry/syscall_32.c:291 > do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:316 > entry_SYSENTER_compat_after_hwframe+0x84/0x8e > RIP: 0023:0xf705f0ec > Code: 90 85 d2 74 0a 89 ce 81 e6 ff 0f 00 00 89 32 85 c0 74 05 c1 e9 0c 89 08 31 c0 5e 5d c3 90 0f 1f 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 58 b8 > RSP: 002b:00000000f683450c EFLAGS: 00000206 ORIG_RAX: 0000000000000036 > RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 000000004020aed2 > RDX: 0000000080000200 RSI: 0000000000000000 RDI: 0000000000000000 > RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 >