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AFNElJ9mwoHuqGSCCnbOKuam0ShO3c2PzhfWAlBBY3fvUS1rRmAdTl1TegvTaIaDpkiqnfqYoHg=@vger.kernel.org X-Gm-Message-State: AOJu0Yw6kGfmk9B2tVkev4ytHXLZonlmrcUgUt98jN1HpMEdCAcHWB0e pm6fD7EumlQ8aHY7v+OBC2LL6nURgAuYHH/3EMqdTVWtpv0rZdsbpm4DML6fIuuP4JJoFL43v16 H9N9jYFO4+xD/Fg7d1wV0jGCECyA4sEaV88SZJx5H0610b/qaFA3R7BIAg80= Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a4a:e84a:0:b0:6a1:42b7:1dfe with SMTP id 006d021491bc7-6a35536a32bmr615101eaf.16.1783351276346; Mon, 06 Jul 2026 08:21:16 -0700 (PDT) Date: Mon, 06 Jul 2026 08:21:16 -0700 In-Reply-To: <20260706092021.3625908-2-twiederh@redhat.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a4bc7ec.57639fcc.86d58.0001.GAE@google.com> Subject: [syzbot ci] Re: KVM: x86: Document and enforce APIC base memory hole From: syzbot ci To: bp@alien8.de, corbet@lwn.net, dave.hansen@linux.intel.com, hpa@zytor.com, kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, pbonzini@redhat.com, seanjc@google.com, skhan@linuxfoundation.org, tglx@kernel.org, twiederh@redhat.com, x86@kernel.org Cc: syzbot@lists.linux.dev, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot ci has tested the following series [v1] KVM: x86: Document and enforce APIC base memory hole https://lore.kernel.org/all/20260706092021.3625908-2-twiederh@redhat.com * [PATCH 1/4] KVM: x86: Document that KVM_CREATE_IRQCHIP must precede vcpu creation * [PATCH 2/4] KVM: x86: Document APIC base address constraint for in-kernel irqchip * [PATCH 3/4] KVM: x86: Reject KVM_CREATE_IRQCHIP if APIC base is already mapped * [PATCH 4/4] KVM: x86: Reject user memory regions covering the APIC base and found the following issue: WARNING: suspicious RCU usage in gfn_to_memslot Full report is available here: https://ci.syzbot.org/series/b02ae7eb-bae2-492f-88f2-fa1b511c93cf *** WARNING: suspicious RCU usage in gfn_to_memslot tree: kvm-next URL: https://kernel.googlesource.com/pub/scm/virt/kvm/kvm/ base: 8cd9520d35a6c38db6567e97dd93b1f11f185dc6 arch: amd64 compiler: Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6 config: https://ci.syzbot.org/builds/2e25da54-5ae8-4f08-889d-30a90ffbe688/config syz repro: https://ci.syzbot.org/findings/707c5fee-46af-42c3-9700-7fc53ef58eb2/syz_repro ============================= WARNING: suspicious RCU usage syzkaller #0 Not tainted ----------------------------- ./include/linux/kvm_host.h:1084 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by syz.0.17/5871: #0: ffff888113334b40 (&kvm->lock){+.+.}-{4:4}, at: kvm_arch_vm_ioctl+0x8d1/0x1990 arch/x86/kvm/x86.c:7320 stack backtrace: CPU: 0 UID: 0 PID: 5871 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 lockdep_rcu_suspicious+0x13f/0x1d0 kernel/locking/lockdep.c:6876 __kvm_memslots include/linux/kvm_host.h:1082 [inline] kvm_memslots include/linux/kvm_host.h:1089 [inline] gfn_to_memslot+0x3df/0x420 virt/kvm/kvm_main.c:2630 kvm_arch_vm_ioctl+0x1590/0x1990 arch/x86/kvm/x86.c:7340 kvm_vm_ioctl+0x8f7/0xd30 virt/kvm/kvm_main.c:5381 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd744b9ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fd7459b7028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fd744e15fa0 RCX: 00007fd744b9ce59 RDX: 0000000000000000 RSI: 000000000000ae60 RDI: 0000000000000004 RBP: 00007fd744c32e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd744e16038 R14: 00007fd744e15fa0 R15: 00007ffe5f70a5a8 *** If these findings have caused you to resend the series or submit a separate fix, please add the following tag to your commit message: Tested-by: syzbot@syzkaller.appspotmail.com --- This report is generated by a bot. It may contain errors. syzbot ci engineers can be reached at syzkaller@googlegroups.com. To test a patch for this bug, please reply with `#syz test` (should be on a separate line). The patch should be attached to the email. Note: arguments like custom git repos and branches are not supported.