kvm guests crash when running "perf kvm top"

From: Seth Forshee
Date: Tue Apr 08 2025 - 12:56:12 EST

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A colleague of mine reported kvm guest hangs when running "perf kvm top"
with a 6.1 kernel. Initially it looked like the problem might be fixed
in newer kernels, but it turned out to be perf changes which must avoid
triggering the issue. I was able to reproduce the guest crashes with
6.15-rc1 in both the host and the guest when using an older version of
perf. A bisect of perf landed on 7b100989b4f6 "perf evlist: Remove
__evlist__add_default", but this doesn't look to be fixing any kind of
issue like this.

This box has an Ice Lake CPU, and we can reproduce on other Ice Lakes
but could not reproduce on another box with Broadwell. On Broadwell
guests would crash with older kernels in the host, but this was fixed by
971079464001 "KVM: x86/pmu: fix masking logic for
MSR_CORE_PERF_GLOBAL_CTRL". That does not fix the issues we see on Ice
Lake.

When the guests crash we aren't getting any output on the serial
console, but I got this from a memory dump:

BUG: unable to handle page fault for address: fffffe76ffbaf00000
BUG: unable to handle page fault for address: fffffe76ffbaf00000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
BUG: unable to handle page fault for address: fffffe76ffbaf00000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 2e044067 P4D 3ec42067 PUD 3ec41067 PMD 3ec40067 PTE ffffffffff120
Oops: Oops: 0002 [#1] SMP NOPTI
BUG: unable to handle page fault for address: fffffe76ffbaf00000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 2e044067 P4D 3ec42067 PUD 3ec41067 PMD 3ec40067 PTE ffffffffff120
Oops: Oops: 0002 [#2] SMP NOPTI
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.15.0-rc1 #3 VOLUNTARY
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009)/Incus, BIOS unknown 02/02/2022
BUG: unable to handle page fault for address: fffffe76ffbaf00000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 2e044067 P4D 3ec42067 PUD 3ec41067 PMD 3ec40067 PTE ffffffffff120
Oops: Oops: 0002 [#3] SMP NOPTI
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.15.0-rc1 #3 VOLUNTARY
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009)/Incus, BIOS unknown 02/02/2022

We got something different though from an ubuntu VM running their 6.8
kernel:

BUG: kernel NULL pointer dereference, address: 000000000000002828
BUG: kernel NULL pointer dereference, address: 000000000000002828
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 10336a067 P4D 0
Oops: 0000 [#1] PREEMPT SMP NOPTI
BUG: kernel NULL pointer dereference, address: 000000000000002828
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 10336a067 P4D 0
Oops: 0000 [#2] PREEMPT SMP NOPTI
BUG: kernel NULL pointer dereference, address: 000000000000002828
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 10336a067 P4D 0
Oops: 0000 [#3] PREEMPT SMP NOPTI
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.8.0-56-generic #58-Ubuntu
BUG: kernel NULL pointer dereference, address: 000000000000002828
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 10336a067 P4D 0
Oops: 0000 [#4] PREEMPT SMP NOPTI
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.8.0-56-generic #58-Ubuntu
BUG: kernel NULL pointer dereference, address: 000000000000002828
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 10336a067 P4D 0
Oops: 0000 [#5] PREEMPT SMP NOPTI
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.8.0-56-generic #58-Ubuntu
RIP: 0010:__sprint_symbol.isra.0+0x6/0x120
Code: ff e8 0e 9d 00 01 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 55 <48> 89 e5 41 57 49 89 f7 41 56 4c 63 f2 4c 8d 45 b8 48 8d 55 c0 41
RSP: 0018:ff25e52d000e6ff8 EFLAGS: 00000046
BUG: #DF stack guard page was hit at 0000000040b441e1 (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)
BUG: #DF stack guard page was hit at 000000002fed44fb (stack is 00000000a1788787..000000008e7f4216)

CPU information from one of the boxes where we see this:

processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 106
model name : Intel(R) Xeon(R) Gold 5318Y CPU @ 2.10GHz
stepping : 6
microcode : 0xd0003f5
cpu MHz : 800.000
cache size : 36864 KB
physical id : 0
siblings : 44
core id : 0
cpu cores : 22
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 27
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb cat_l3 intel_ppin ssbd mba ibrs ibpb stibp ibrs_enhanced tpr_shadow flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid cqm rdt_a avx512f avx512dq rdseed adx smap avx512ifma clflushopt clwb intel_pt avx512cd sha_ni avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local split_lock_detect wbnoinvd dtherm ida arat pln pts hwp hwp_act_window hwp_epp hwp_pkg_req vnmi avx512vbmi umip pku ospke avx512_vbmi2 gfni vaes vpclmulqdq avx512_vnni avx512_bitalg avx512_vpopcntdq la57 rdpid fsrm md_clear pconfig flush_l1d arch_capabilities
vmx flags : vnmi preemption_timer posted_intr invvpid ept_x_only ept_ad ept_1gb ept_5level flexpriority apicv tsc_offset vtpr mtf vapic ept vpid unrestricted_guest vapic_reg vid ple shadow_vmcs pml ept_violation_ve ept_mode_based_exec tsc_scaling
bugs : spectre_v1 spectre_v2 spec_store_bypass swapgs mmio_stale_data eibrs_pbrsb gds bhi spectre_v2_user
bogomips : 4000.00
clflush size : 64
cache_alignment : 64
address sizes : 46 bits physical, 57 bits virtual
power management:

Let me know if I can provide any additional information or testing.

Thanks,
Seth

Next message: Paolo Bonzini: "Re: [PATCH 29/67] KVM: SVM: Stop walking list of routing table entries when updating IRTE"
Previous message: Alex Hung: "Re: [PATCH] drm/amd/display: do not copy invalid CRTC timing info"
Next in thread: Sean Christopherson: "Re: kvm guests crash when running "perf kvm top""
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