* Re: [syzbot] [kvm?] WARNING in kvm_put_kvm (3) [not found] <6a78d191.b50370da.49fe0.0042.GAE@google.com> @ 2026-09-14 7:03 ` syzbot 2026-09-14 11:55 ` Zqiang 0 siblings, 1 reply; 2+ messages in thread From: syzbot @ 2026-09-14 7:03 UTC (permalink / raw) To: frederic, jiangshanlai, josh, kvm, linux-kernel, mathieu.desnoyers, paulmck, pbonzini, qiang.zhang, rcu, rostedt, seanjc, shpark061104, syzkaller-bugs, work syzbot has found a reproducer for 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=1779e925580000 kernel config: https://syzkaller.appspot.com/x/.config?x=5e4e3a0e188a497e dashboard link: https://syzkaller.appspot.com/bug?extid=d4faf7db59e11f6fd1ab 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=14ef08c9580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10f9e925580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/daf497619736/disk-50d05c7c.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/748fbd82f647/vmlinux-50d05c7c.xz kernel image: https://storage.googleapis.com/syzbot-assets/e61c59099d07/bzImage-50d05c7c.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+d4faf7db59e11f6fd1ab@syzkaller.appspotmail.com ------------[ cut here ]------------ timer_delete_sync(&sdp->delay_work) && rcu_segcblist_n_cbs(&sdp->srcu_cblist) WARNING: kernel/rcu/srcutree.c:707 at cleanup_srcu_struct+0x3d6/0x8b0 kernel/rcu/srcutree.c:706, CPU#0: syz.0.4746/16077 Modules linked in: CPU: 0 UID: 0 PID: 16077 Comm: syz.0.4746 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:cleanup_srcu_struct+0x3d6/0x8b0 kernel/rcu/srcutree.c:706 Code: fd 8b 00 48 83 7d 00 00 4c 8b 74 24 10 0f 85 dd 03 00 00 41 ff c5 41 83 e5 0f 41 83 fd 07 0f 86 e2 fe ff ff e9 ab 00 00 00 90 <0f> 0b 90 4c 8d b5 00 02 00 00 4c 89 f3 48 c1 eb 03 48 b8 00 00 00 RSP: 0018:ffffc90002e2fc10 EFLAGS: 00010206 RAX: 1ffffd1ffff8ff4d RBX: 0000607edafad980 RCX: dffffc0000000000 RDX: 0000000000000001 RSI: ffffffff8e475f59 RDI: 00000000ffffffff RBP: ffffe8ffffc7f980 R08: ffffffff907a2b7f R09: 1ffffffff20f456f R10: dffffc0000000000 R11: fffffbfff20f4570 R12: ffff88802b081000 R13: 0000000000000000 R14: ffffe8ffffc7fa68 R15: 1ffffffff1ce91de FS: 0000000000000000(0000) GS:ffff888124cd2000(0063) knlGS:0000000057310480 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000073e86000 CR4: 00000000003526f0 Call Trace: <TASK> kvm_destroy_vm virt/kvm/kvm_main.c:1303 [inline] kvm_put_kvm+0x9cb/0xb50 virt/kvm/kvm_main.c:1332 kvm_vm_release+0x43/0x50 virt/kvm/kvm_main.c:1355 __fput+0x418/0xa50 fs/file_table.c:512 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:70 [inline] exit_to_user_mode_loop+0x204/0x770 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:336 [inline] __do_fast_syscall_32+0x437/0x6a0 arch/x86/entry/syscall_32.c:294 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:316 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7f470ec 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:00000000ffa0002c EFLAGS: 00000206 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 000000000000001e RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 </TASK> ---------------- Code disassembly (best guess): 0: 90 nop 1: 85 d2 test %edx,%edx 3: 74 0a je 0xf 5: 89 ce mov %ecx,%esi 7: 81 e6 ff 0f 00 00 and $0xfff,%esi d: 89 32 mov %esi,(%rdx) f: 85 c0 test %eax,%eax 11: 74 05 je 0x18 13: c1 e9 0c shr $0xc,%ecx 16: 89 08 mov %ecx,(%rax) 18: 31 c0 xor %eax,%eax 1a: 5e pop %rsi 1b: 5d pop %rbp 1c: c3 ret 1d: 90 nop 1e: 0f 1f 00 nopl (%rax) 21: 51 push %rcx 22: 52 push %rdx 23: 55 push %rbp 24: 89 e5 mov %esp,%ebp 26: 0f 34 sysenter 28: cd 80 int $0x80 * 2a: 5d pop %rbp <-- trapping instruction 2b: 5a pop %rdx 2c: 59 pop %rcx 2d: c3 ret 2e: 90 nop 2f: 90 nop 30: 90 nop 31: 90 nop 32: 90 nop 33: 90 nop 34: 90 nop 35: 90 nop 36: 90 nop 37: 90 nop 38: 90 nop 39: 90 nop 3a: 90 nop 3b: 90 nop 3c: 90 nop 3d: 90 nop 3e: 58 pop %rax 3f: b8 .byte 0xb8 --- 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. ^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [syzbot] [kvm?] WARNING in kvm_put_kvm (3) 2026-09-14 7:03 ` [syzbot] [kvm?] WARNING in kvm_put_kvm (3) syzbot @ 2026-09-14 11:55 ` Zqiang 0 siblings, 0 replies; 2+ messages in thread From: Zqiang @ 2026-09-14 11:55 UTC (permalink / raw) To: syzbot, frederic, jiangshanlai, josh, kvm, linux-kernel, mathieu.desnoyers, paulmck, pbonzini, rcu, rostedt, seanjc, shpark061104, syzkaller-bugs, work > > syzbot has found a reproducer for 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=1779e925580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=5e4e3a0e188a497e > dashboard link: https://syzkaller.appspot.com/bug?extid=d4faf7db59e11f6fd1ab > 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=14ef08c9580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10f9e925580000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/daf497619736/disk-50d05c7c.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/748fbd82f647/vmlinux-50d05c7c.xz > kernel image: https://storage.googleapis.com/syzbot-assets/e61c59099d07/bzImage-50d05c7c.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+d4faf7db59e11f6fd1ab@syzkaller.appspotmail.com > > ------------[ cut here ]------------ > timer_delete_sync(&sdp->delay_work) && rcu_segcblist_n_cbs(&sdp->srcu_cblist) > WARNING: kernel/rcu/srcutree.c:707 at cleanup_srcu_struct+0x3d6/0x8b0 kernel/rcu/srcutree.c:706, CPU#0: syz.0.4746/16077 This should be fixed: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git 91153bd0ee7f ("srcu: Fix WARN_ON() for rcu_segcblist_n_cbs() in cleanup_srcu_struct()") Thanks Zqiang > Modules linked in: > CPU: 0 UID: 0 PID: 16077 Comm: syz.0.4746 Not tainted syzkaller #0 PREEMPT(full) > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 > RIP: 0010:cleanup_srcu_struct+0x3d6/0x8b0 kernel/rcu/srcutree.c:706 > Code: fd 8b 00 48 83 7d 00 00 4c 8b 74 24 10 0f 85 dd 03 00 00 41 ff c5 41 83 e5 0f 41 83 fd 07 0f 86 e2 fe ff ff e9 ab 00 00 00 90 <0f> 0b 90 4c 8d b5 00 02 00 00 4c 89 f3 48 c1 eb 03 48 b8 00 00 00 > RSP: 0018:ffffc90002e2fc10 EFLAGS: 00010206 > RAX: 1ffffd1ffff8ff4d RBX: 0000607edafad980 RCX: dffffc0000000000 > RDX: 0000000000000001 RSI: ffffffff8e475f59 RDI: 00000000ffffffff > RBP: ffffe8ffffc7f980 R08: ffffffff907a2b7f R09: 1ffffffff20f456f > R10: dffffc0000000000 R11: fffffbfff20f4570 R12: ffff88802b081000 > R13: 0000000000000000 R14: ffffe8ffffc7fa68 R15: 1ffffffff1ce91de > FS: 0000000000000000(0000) GS:ffff888124cd2000(0063) knlGS:0000000057310480 > CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 > CR2: 0000000000000000 CR3: 0000000073e86000 CR4: 00000000003526f0 > Call Trace: > <TASK> > kvm_destroy_vm virt/kvm/kvm_main.c:1303 [inline] > kvm_put_kvm+0x9cb/0xb50 virt/kvm/kvm_main.c:1332 > kvm_vm_release+0x43/0x50 virt/kvm/kvm_main.c:1355 > __fput+0x418/0xa50 fs/file_table.c:512 > task_work_run+0x1d9/0x270 kernel/task_work.c:233 > resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] > __exit_to_user_mode_loop kernel/entry/common.c:70 [inline] > exit_to_user_mode_loop+0x204/0x770 kernel/entry/common.c:101 > __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] > syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] > syscall_exit_to_user_mode include/linux/entry-common.h:336 [inline] > __do_fast_syscall_32+0x437/0x6a0 arch/x86/entry/syscall_32.c:294 > do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:316 > entry_SYSENTER_compat_after_hwframe+0x84/0x8e > RIP: 0023:0xf7f470ec > 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:00000000ffa0002c EFLAGS: 00000206 ORIG_RAX: 00000000000001b4 > RAX: 0000000000000000 RBX: 0000000000000003 RCX: 000000000000001e > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 > RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 > </TASK> > ---------------- > Code disassembly (best guess): > 0: 90 nop > 1: 85 d2 test %edx,%edx > 3: 74 0a je 0xf > 5: 89 ce mov %ecx,%esi > 7: 81 e6 ff 0f 00 00 and $0xfff,%esi > d: 89 32 mov %esi,(%rdx) > f: 85 c0 test %eax,%eax > 11: 74 05 je 0x18 > 13: c1 e9 0c shr $0xc,%ecx > 16: 89 08 mov %ecx,(%rax) > 18: 31 c0 xor %eax,%eax > 1a: 5e pop %rsi > 1b: 5d pop %rbp > 1c: c3 ret > 1d: 90 nop > 1e: 0f 1f 00 nopl (%rax) > 21: 51 push %rcx > 22: 52 push %rdx > 23: 55 push %rbp > 24: 89 e5 mov %esp,%ebp > 26: 0f 34 sysenter > 28: cd 80 int $0x80 > * 2a: 5d pop %rbp <-- trapping instruction > 2b: 5a pop %rdx > 2c: 59 pop %rcx > 2d: c3 ret > 2e: 90 nop > 2f: 90 nop > 30: 90 nop > 31: 90 nop > 32: 90 nop > 33: 90 nop > 34: 90 nop > 35: 90 nop > 36: 90 nop > 37: 90 nop > 38: 90 nop > 39: 90 nop > 3a: 90 nop > 3b: 90 nop > 3c: 90 nop > 3d: 90 nop > 3e: 58 pop %rax > 3f: b8 .byte 0xb8 > > --- > 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. > ^ permalink raw reply [flat|nested] 2+ messages in thread
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[not found] <6a78d191.b50370da.49fe0.0042.GAE@google.com>
2026-09-14 7:03 ` [syzbot] [kvm?] WARNING in kvm_put_kvm (3) syzbot
2026-09-14 11:55 ` Zqiang
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