[moderation/CI] Re: Cleaning up the KVM clock mess

0 views
Skip to first unread message

syzbot ci

unread,
Jul 29, 2026, 5:27:10 PM (9 days ago) Jul 29
to syzkaller-upst...@googlegroups.com, syz...@lists.linux.dev
syzbot ci has tested the following series

[v7] Cleaning up the KVM clock mess
https://lore.kernel.org/all/20260728144954...@infradead.org
* [PATCH v7 01/36] KVM: x86: Improve accuracy of KVM clock when TSC scaling is in force
* [PATCH v7 02/36] KVM: x86: Explicitly disable TSC scaling without CONSTANT_TSC
* [PATCH v7 03/36] KVM: x86: Activate master clock immediately on vCPU creation
* [PATCH v7 04/36] KVM: x86: Avoid NTP frequency skew for KVM clock on 32-bit host
* [PATCH v7 05/36] KVM: x86: Fold __get_kvmclock() into get_kvmclock()
* [PATCH v7 06/36] KVM: x86: Drop CPU pinning in get_kvmclock()
* [PATCH v7 07/36] KVM: x86: Restructure get_kvmclock()
* [PATCH v7 08/36] KVM: x86: Fix KVM clock precision in get_kvmclock() with TSC scaling
* [PATCH v7 09/36] KVM: x86: Use get_kvmclock() in kvm_get_wall_clock_epoch()
* [PATCH v7 10/36] KVM: x86: Fix compute_guest_tsc() to handle negative time deltas
* [PATCH v7 11/36] KVM: x86: Restructure kvm_guest_time_update() for TSC upscaling
* [PATCH v7 12/36] KVM: x86: Simplify and comment kvm_get_time_scale()
* [PATCH v7 13/36] KVM: x86: Remove implicit rdtsc() from kvm_compute_l1_tsc_offset()
* [PATCH v7 14/36] KVM: x86: Improve synchronization in kvm_synchronize_tsc()
* [PATCH v7 15/36] KVM: x86: Kill last_tsc_{nsec,write,offset} fields
* [PATCH v7 16/36] KVM: x86: Replace nr_vcpus_matched_tsc count with all_vcpus_matched_tsc bool
* [PATCH v7 17/36] KVM: x86: Allow KVM master clock mode when TSCs are offset from each other
* [PATCH v7 18/36] KVM: x86: Factor out kvm_use_master_clock()
* [PATCH v7 19/36] KVM: x86: Avoid gratuitous global clock updates
* [PATCH v7 20/36] KVM: x86/xen: Prevent runstate times from becoming negative
* [PATCH v7 21/36] KVM: x86: Avoid redundant masterclock updates from multiple vCPUs
* [PATCH v7 22/36] KVM: x86: Remove runtime Xen TSC frequency CPUID update
* [PATCH v7 23/36] KVM: x86: Re-synchronize TSC after KVM_SET_TSC_KHZ
* [PATCH v7 24/36] KVM: x86: Use ktime_get_snapshot_id() for master clock
* [PATCH v7 25/36] KVM: x86: Compute kvmclock base without pvclock_gtod_data
* [PATCH v7 26/36] KVM: x86: Cache host vclock_mode for masterclock eligibility checks
* [PATCH v7 27/36] KVM: x86: Remove pvclock_gtod_data and private timekeeping code
* [PATCH v7 28/36] KVM: x86: Activate master clock from kvm_arch_init_vm()
* [PATCH v7 29/36] UAPI: x86: Move pvclock-abi to UAPI for x86 platforms
* [PATCH v7 30/36] KVM: selftests: Use UAPI pvclock-abi.h in xen_shinfo_test
* [PATCH v7 31/36] KVM: x86: Add KVM_[GS]ET_CLOCK_GUEST for accurate KVM clock migration
* [PATCH v7 32/36] KVM: x86: Add KVM_VCPU_TSC_SCALE and fix the documentation on TSC migration
* [PATCH v7 33/36] KVM: selftests: Add KVM/PV clock selftest to prove timer correction
* [PATCH v7 34/36] KVM: selftests: Add master clock offset test
* [PATCH v7 35/36] KVM: selftests: Add Xen/generic CPUID timing leaf test
* [PATCH v7 36/36] KVM: selftests: Add Xen runstate migration test

and found the following issue:
kernel build error

Full report is available here:
https://ci.syzbot.org/series/d9831298-9bd0-48af-8723-35fb5dfd0d61

***

kernel build error

tree: kvm-next
URL: https://kernel.googlesource.com/pub/scm/virt/kvm/kvm/
base: a204badd8432f93b7e862e7dac6db0fe3d65f370
arch: amd64
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
config: https://ci.syzbot.org/builds/f94277a2-d36b-4aee-8a28-5c6042355c18/config

arch/x86/kvm/x86.c:1418:13: error: no member named 'valid' in 'struct system_time_snapshot'
arch/x86/kvm/x86.c:1426:12: error: no member named 'hw_csid' in 'struct system_time_snapshot'
arch/x86/kvm/x86.c:1426:45: error: no member named 'hw_cycles' in 'struct system_time_snapshot'
arch/x86/kvm/x86.c:1427:26: error: no member named 'hw_cycles' in 'struct system_time_snapshot'
arch/x86/kvm/x86.c:1438:2: error: call to undeclared function 'ktime_get_snapshot_id'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
arch/x86/kvm/x86.c:1442:50: error: no member named 'systime' in 'struct system_time_snapshot'
arch/x86/kvm/x86.c:1454:2: error: call to undeclared function 'ktime_get_snapshot_id'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
arch/x86/kvm/x86.c:1458:32: error: no member named 'systime' in 'struct system_time_snapshot'
arch/x86/kvm/x86.c:1474:2: error: call to undeclared function 'ktime_get_snapshot_id'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
arch/x86/kvm/x86.c:1478:33: error: no member named 'systime' in 'struct system_time_snapshot'

***

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: syz...@syzkaller.appspotmail.com

---
This report is generated by a bot. It may contain errors.
syzbot ci engineers can be reached at syzk...@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.

The email will later be sent to:
[boris.o...@oracle.com b...@alien8.de cor...@lwn.net dave....@linux.intel.com dongli...@oracle.com dw...@infradead.org h...@zytor.com jall...@amazon.com jgr...@suse.com ji...@kernel.org joe...@oracle.com joey....@arm.com k...@vger.kernel.org linu...@vger.kernel.org linux-...@vger.kernel.org linux-k...@vger.kernel.org m...@kernel.org mi...@redhat.com pa...@xen.org pbon...@redhat.com sascha....@arm.com sea...@google.com sk...@linuxfoundation.org tg...@kernel.org vkuz...@redhat.com x...@kernel.org xen-...@lists.xenproject.org]

If the report looks fine to you, reply with:
#syz upstream

If the report is a false positive, reply with
#syz invalid

David Woodhouse

unread,
Jul 30, 2026, 4:36:52 AM (8 days ago) Jul 30
to syzbot ci, syzkaller-upst...@googlegroups.com, syz...@lists.linux.dev
#syz invalid

The series (or at least patch 01/36) was posted with

base-commit: 271255273d5ff348fe29d89fe4712b2f7f7907c3

which is the tip of kvm-x86/next and contains the timekeeping
prerequisites (ktime_get_snapshot_id() et al). The CI applied it to a
kvm-next tree at a204badd8432 which predates them, hence the build
failure. Wrong base tree, not a bug in the series.

Aleksandr Nogikh

unread,
Jul 30, 2026, 9:40:18 AM (8 days ago) Jul 30
to David Woodhouse, syzbot ci, syzkaller-upst...@googlegroups.com, syz...@lists.linux.dev
Thanks for triaging this report!

The CI did recognize the base commit, but it didn't know about the
kvm-x86 tree, so couldn't fetch it.
I've added it in
https://github.com/google/syzkaller/commit/285e8c809b7ce04c728f02b57698320bcc0efa48

--
Aleksandr
> --
> You received this message because you are subscribed to the Google Groups "syzkaller-upstream-moderation" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-upstream-m...@googlegroups.com.
> To view this discussion visit https://groups.google.com/d/msgid/syzkaller-upstream-moderation/b5e3e5c81ebcbf4f6a793b89463e4979fc7cba4d.camel%40infradead.org.
Reply all
Reply to author
Forward
0 new messages