WARNING in switch_fpu_return

Status: fixed on 2020/03/25 19:36
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+f2ca20d4aa1408b0385a@syzkaller.appspotmail.com
Fix commit: 2620fe268e80 KVM: x86: Revert "KVM: X86: Fix fpu state crash in kvm guest"
First crash: 2398d, last: 2361d
Cause bisection: introduced by (bisect log) :
commit 92e6475ae0a0383b012eb21c1aaf0e5456b1a3d9
Author: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Date: Wed Jul 3 14:02:39 2019 +0000

  drm/amd/display: Set enabled to false at start of audio disable

Crash: no output from test machine (log)
Repro: syz .config
  
Fix bisection: fixed by (bisect log) :
commit 3009afc6e39e78708d8fb444ae50544b3bcd3a3f
Author: Sean Christopherson <sean.j.christopherson@intel.com>
Date: Wed Jan 22 04:43:39 2020 +0000

  KVM: x86: Use a typedef for fastop functions

  
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
WARNING in switch_fpu_return 5 (7) 2020/03/23 15:01
▶ ▼ Fix bisection attempts (2)
Created Duration User Patch Repo Result
2020/03/22 18:15 4h25m bisect fix upstream OK (1) job log
2020/02/04 06:52 28m bisect fix upstream OK (0) job log log

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 10009 at arch/x86/include/asm/fpu/internal.h:539 __fpregs_load_activate arch/x86/include/asm/fpu/internal.h:539 [inline]
WARNING: CPU: 0 PID: 10009 at arch/x86/include/asm/fpu/internal.h:539 switch_fpu_return+0x437/0x4f0 arch/x86/kernel/fpu/core.c:343
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 10009 Comm: kworker/0:4 Not tainted 5.5.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events async_pf_execute
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 panic+0x2e3/0x75c kernel/panic.c:221
 __warn.cold+0x2f/0x3e kernel/panic.c:582
 report_bug+0x289/0x300 lib/bug.c:195
 fixup_bug arch/x86/kernel/traps.c:174 [inline]
 fixup_bug arch/x86/kernel/traps.c:169 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267
 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286
 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027
RIP: 0010:__fpregs_load_activate arch/x86/include/asm/fpu/internal.h:539 [inline]
RIP: 0010:switch_fpu_return+0x437/0x4f0 arch/x86/kernel/fpu/core.c:343
Code: 0f 94 c6 31 ff 44 89 f6 e8 06 8f 4a 00 45 84 f6 0f 84 7f fd ff ff e8 b8 8d 4a 00 e8 a4 c9 d5 ff e9 70 fd ff ff e8 a9 8d 4a 00 <0f> 0b e9 b6 fd ff ff e8 9d 8d 4a 00 0f 0b e9 18 fd ff ff e8 91 8d
RSP: 0018:ffffc900020afa80 EFLAGS: 00010293
RAX: ffff888092434500 RBX: ffff888092434500 RCX: ffffffff812a9ccf
RDX: 0000000000000000 RSI: ffffffff812aa047 RDI: 0000000000000005
RBP: ffffc900020afb10 R08: ffff888092434500 R09: ffffed10124868a1
R10: ffffed10124868a0 R11: ffff888092434507 R12: 1ffff92000415f51
R13: ffff888092435a00 R14: 0000000000200000 R15: ffffc900020afae8
 kvm_arch_vcpu_load+0x66e/0x950 arch/x86/kvm/x86.c:3463
 vcpu_load+0x43/0x90 arch/x86/kvm/../../../virt/kvm/kvm_main.c:201
 kvm_unload_vcpu_mmu arch/x86/kvm/x86.c:9543 [inline]
 kvm_free_vcpus arch/x86/kvm/x86.c:9558 [inline]
 kvm_arch_destroy_vm+0x184/0x5f0 arch/x86/kvm/x86.c:9663
 kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:816 [inline]
 kvm_put_kvm+0x5a5/0xcc0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:837
 async_pf_execute+0x3bf/0x800 arch/x86/kvm/../../../virt/kvm/async_pf.c:101
 process_one_work+0x9af/0x1740 kernel/workqueue.c:2264
 worker_thread+0x98/0xe40 kernel/workqueue.c:2410
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (11):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/12/29 14:53 upstream bf8d1cd43865 af6b8ef8 .config console log report syz ci-upstream-kasan-gce-selinux-root
2019/12/29 13:18 upstream bf8d1cd43865 af6b8ef8 .config console log report syz ci-upstream-kasan-gce-selinux-root
2019/12/29 07:05 upstream bf8d1cd43865 af6b8ef8 .config console log report syz ci-upstream-kasan-gce-root
2019/12/29 04:03 upstream bf8d1cd43865 af6b8ef8 .config console log report syz ci-upstream-kasan-gce-root
2019/12/29 07:08 upstream bf8d1cd43865 af6b8ef8 .config console log report syz ci-upstream-kasan-gce-386
2019/12/29 03:37 upstream bf8d1cd43865 af6b8ef8 .config console log report syz ci-upstream-kasan-gce-386
2020/01/05 04:05 linux-next 7ddd09fc4b74 68256974 .config console log report syz ci-upstream-linux-next-kasan-gce-root
2020/01/05 01:41 linux-next 7ddd09fc4b74 68256974 .config console log report syz ci-upstream-linux-next-kasan-gce-root
2019/12/30 22:22 upstream fd6988496e79 af6b8ef8 .config console log report ci-upstream-kasan-gce
2019/12/29 02:17 upstream bf8d1cd43865 af6b8ef8 .config console log report ci-upstream-kasan-gce
2019/12/29 02:14 upstream bf8d1cd43865 af6b8ef8 .config console log report ci-upstream-kasan-gce-386
* Struck through repros no longer work on HEAD.