Re: [i915-ci-only NO-REVIEW 24/25] PREEMPT_RT injection

From: kernel test robot

Date: Fri Feb 27 2026 - 20:58:36 EST

Hello,

since we cannot understand well the purpose of this patch set, this report is
just FYI what we observed in our tests.

by this commit, a big config diff is introduced comparing to parent [1]

then a boot test which can pass on parent now fails with a high rate.

=========================================================================================
tbox_group/testcase/rootfs/kconfig/compiler/sleep:
vm-snb/boot/quantal-x86_64-core-20190426.cgz/x86_64-rhel-9.4-rust/clang-20/1

commit:
822dafa31719f2 ("Revert "drm/i915: Depend on !PREEMPT_RT."")
7bb9eedbc87d82 ("PREEMPT_RT injection")

822dafa31719f205 7bb9eedbc87d8256eebc7edfd24
---------------- ---------------------------
fail:runs %reproduction fail:runs
| | |
:100 87% 87:100 dmesg.BUG:kernel_reboot-without-warning_in_test_stage

unfortunately, we cannot find more useful information in dmesg.

below is full report FYI.

kernel test robot noticed "BUG:kernel_reboot-without-warning_in_test_stage" on:

commit: 7bb9eedbc87d8256eebc7edfd240cb0cdf42e667 ("[i915-ci-only NO-REVIEW 24/25] PREEMPT_RT injection")
url: https://github.com/intel-lab-lkp/linux/commits/Maarten-Lankhorst/drm-vblank_work-Add-methods-to-schedule-vblank_work-in-2-stages/20260226-012447
base: https://gitlab.freedesktop.org/drm/i915/kernel.git for-linux-next
patch link: https://lore.kernel.org/all/20260225131931.60724-25-dev@xxxxxxxxxxxx/
patch subject: [i915-ci-only NO-REVIEW 24/25] PREEMPT_RT injection

in testcase: boot

config: x86_64-rhel-9.4-rust
compiler: clang-20
test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 32G

(please refer to attached dmesg/kmsg for entire log/backtrace)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-lkp/202602280933.d4221030-lkp@xxxxxxxxx

LKP: ttyS0: 101: /lkp/lkp/src/bin/run-lkp /lkp/jobs/scheduled/vm-meta-207/boot-1-quantal-x86_64-core-20190426.cgz-7bb9eedbc87d-20260227-2306906-1p6guj1-96.yaml[ 27.416092][ T127] INFO: lkp CACHE_DIR is /tmp/cache
[ 27.416099][ T127]

[ 27.490291][ T255] ata2: found unknown device (class 0)
[ 27.493888][ T255] ata2.00: ATAPI: QEMU DVD-ROM, 2.5+, max UDMA/100
[ 27.495381][ T127] LKP: stdout: 101: /lkp/lkp/src/bin/run-lkp /lkp/jobs/scheduled/vm-meta-207/boot-1-quantal-x86_64-core-20190426.cgz-7bb9eedbc87d-20260227-2306906-1p6guj1-96.yaml
[ 27.495388][ T127]
[ 27.510194][ T37] scsi 1:0:0:0: CD-ROM QEMU QEMU DVD-ROM 2.5+ PQ: 0 ANSI: 5
[ 27.591664][ T127] RESULT_ROOT=/result/boot/1/vm-snb/quantal-x86_64-core-20190426.cgz/x86_64-rhel-9.4-rust/clang-20/7bb9eedbc87d8256eebc7edfd240cb0cdf42e667/0
[ 27.591672][ T127]
[ 27.613781][ T127] job=/lkp/jobs/scheduled/vm-meta-207/boot-1-quantal-x86_64-core-20190426.cgz-7bb9eedbc87d-20260227-2306906-1p6guj1-96.yaml
[ 27.613791][ T127]
[ 27.660154][ T219] bochs-drm 0000:00:02.0: vgaarb: deactivate vga console
[ 27.667222][ T219] Console: switching to colour dummy device 80x25
[ 27.669389][ T219] [drm] Found bochs VGA, ID 0xb0c5.
[ 27.669392][ T219] [drm] Framebuffer size 16384 kB @ 0xfd000000, mmio @ 0xfebf0000.
[ 27.682301][ T127] result_service: raw_upload, RESULT_MNT: /internal-lkp-server/result, RESULT_ROOT: /internal-lkp-server/result/boot/1/vm-snb/quantal-x86_64-core-20190426.cgz/x86_64-rhel-9.4-rust/clang-20/7bb9eedbc87d8256eebc7edfd240cb0cdf42e667/0, TMP_RESULT_ROOT: /tmp/lkp/result
[ 27.682309][ T127]
[ 27.685840][ T219] [drm] Initialized bochs-drm 1.0.0 for 0000:00:02.0 on minor 0
[ 27.747112][ T301] parport_pc 00:03: reported by Plug and Play ACPI
[ 27.747359][ T301] parport0: PC-style at 0x378, irq 7 [PCSPP,TRISTATE]
[ 27.749822][ T219] fbcon: bochs-drmdrmfb (fb0) is primary device
[ 27.766802][ T127] run-job /lkp/jobs/scheduled/vm-meta-207/boot-1-quantal-x86_64-core-20190426.cgz-7bb9eedbc87d-20260227-2306906-1p6guj1-96.yaml
[ 27.766807][ T127]
[ 27.853871][ T219] Console: switching to colour frame buffer device 160x50
[ 27.867424][ T127] /usr/bin/wget -q --timeout=3600 --tries=1 --local-encoding=UTF-8 http://internal-lkp-server:80/~lkp/cgi-bin/lkp-jobfile-append-var?job_file=/lkp/jobs/scheduled/vm-meta-207/boot-1-quantal-x86_64-core-20190426.cgz-7bb9eedbc87d-20260227-2306906-1p6guj1-96.yaml&job_state=running -O /dev/null
[ 27.867435][ T127]
[ 27.897905][ T219] bochs-drm 0000:00:02.0: [drm] fb0: bochs-drmdrmfb frame buffer device
[ 27.989445][ T1] init: failsafe main process (349) killed by TERM signal
[ 28.051819][ T380] ppdev: user-space parallel port driver
[ 28.093899][ T376] sr 1:0:0:0: [sr0] scsi3-mmc drive: 4x/4x cd/rw xa/form2 tray
[ 28.093909][ T376] cdrom: Uniform CD-ROM driver Revision: 3.20
[ 28.107727][ T376] sr 1:0:0:0: Attached scsi CD-ROM sr0
[ 28.357355][ T1] init: networking main process (446) terminated with status 1
[ 28.769126][ T127] target ucode:
[ 28.769138][ T127]
[ 28.804304][ T127] check_nr_cpu
[ 28.804312][ T127]
[ 28.812567][ T127] CPU(s): 2
[ 28.812573][ T127]
[ 28.814711][ T127] On-line CPU(s) list: 0,1
[ 28.814715][ T127]
[ 28.816753][ T127] Thread(s) per core: 1
[ 28.816758][ T127]
[ 28.818021][ T127] Core(s) per socket: 2
[ 28.818026][ T127]
[ 28.819871][ T127] Socket(s): 1
[ 28.819876][ T127]
[ 28.820808][ T127] NUMA node(s): 1
[ 28.820812][ T127]
[ 28.821855][ T127] NUMA node0 CPU(s): 0,1
[ 28.821859][ T127]
[ 29.964375][ T127] sleep started
[ 29.964382][ T127]
[ 31.014164][ T127] /usr/bin/wget -q --timeout=3600 --tries=1 --local-encoding=UTF-8 http://internal-lkp-server:80/~lkp/cgi-bin/lkp-jobfile-append-var?job_file=/lkp/jobs/scheduled/vm-meta-207/boot-1-quantal-x86_64-core-20190426.cgz-7bb9eedbc87d-20260227-2306906-1p6guj1-96.yaml&job_state=post_run -O /dev/null
[ 31.014174][ T127]
[ 32.999598][ T127] kill 490 vmstat -n 1
[ 32.999606][ T127]
[ 33.010867][ T127] kill 487 cat /proc/kmsg
[ 33.010876][ T127]
[ 33.029622][ T127] kill 510 /bin/sh /lkp/lkp/src/programs/watchdog/monitor
[ 33.029629][ T127]
[ 33.034143][ T127] wait for background processes: 504
[ 33.034150][ T127]
[ 33.034420][ T127] monitor
[ 33.034422][ T127]
[ 37.395968][ T127] /usr/bin/wget -q --timeout=3600 --tries=1 --local-encoding=UTF-8 http://internal-lkp-server:80/~lkp/cgi-bin/lkp-jobfile-append-var?job_file=/lkp/jobs/scheduled/vm-meta-207/boot-1-quantal-x86_64-core-20190426.cgz-7bb9eedbc87d-20260227-2306906-1p6guj1-96.yaml&loadavg=0.89%200.25%200.08%202/122%20635&start_time=1772215785&end_time=1772215786&version=/lkp/lkp/.src-20260227-121815:db3bc08cea0e:bc832e21160e-dirty&; -O /dev/null
[ 37.395986][ T127]
[ 38.230850][ T127] /usr/bin/wget -q --timeout=3600 --tries=1 --local-encoding=UTF-8 http://internal-lkp-server:80/~lkp/cgi-bin/lkp-jobfile-append-var?job_file=/lkp/jobs/scheduled/vm-meta-207/boot-1-quantal-x86_64-core-20190426.cgz-7bb9eedbc87d-20260227-2306906-1p6guj1-96.yaml&job_state=finished -O /dev/null
[ 38.230880][ T127]
LKP: ttyS0: 101: LKP: tbox cant kexec and rebooting forcely
[ 39.153116][ T127] LKP: stdout: 101: LKP: tbox cant kexec and rebooting forcely
[ 39.153123][ T127]
[ 39.231552][ T127] /usr/bin/wget -q --timeout=3600 --tries=1 --local-encoding=UTF-8 http://internal-lkp-server:80/~lkp/cgi-bin/lkp-wtmp?tbox_name=vm-snb&tbox_state=rebooting_cant_kexec&job_file=/lkp/jobs/scheduled/vm-meta-207/boot-1-quantal-x86_64-core-20190426.cgz-7bb9eedbc87d-20260227-2306906-1p6guj1-96.yaml -O /dev/null
[ 39.231562][ T127]
BUG: kernel reboot-without-warning in test stage

The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20260228/202602280933.d4221030-lkp@xxxxxxxxx

[1]
--- /pkg/linux/x86_64-rhel-9.4-rust/clang-20/822dafa31719f20589ae143ae18bfaa881f7785d/.config 2026-02-27 17:10:20.025441468 +0800
+++ /pkg/linux/x86_64-rhel-9.4-rust/clang-20/7bb9eedbc87d8256eebc7edfd240cb0cdf42e667/.config 2026-02-27 16:36:20.788050773 +0800
@@ -139,6 +139,8 @@ CONFIG_PREEMPT_BUILD=y
CONFIG_ARCH_HAS_PREEMPT_LAZY=y
# CONFIG_PREEMPT is not set
CONFIG_PREEMPT_LAZY=y
+CONFIG_PREEMPT_RT=y
+# CONFIG_PREEMPT_RT_NEEDS_BH_LOCK is not set
CONFIG_PREEMPT_COUNT=y
CONFIG_PREEMPTION=y
CONFIG_PREEMPT_DYNAMIC=y
@@ -177,8 +179,11 @@ CONFIG_TASKS_RUDE_RCU=y
CONFIG_TASKS_TRACE_RCU=y
CONFIG_RCU_STALL_COMMON=y
CONFIG_RCU_NEED_SEGCBLIST=y
+CONFIG_RCU_BOOST=y
+CONFIG_RCU_BOOST_DELAY=500
CONFIG_RCU_NOCB_CPU=y
# CONFIG_RCU_NOCB_CPU_DEFAULT_ALL is not set
+CONFIG_RCU_NOCB_CPU_CB_BOOST=y
# CONFIG_RCU_LAZY is not set
# end of RCU Subsystem

@@ -203,8 +208,6 @@ CONFIG_CC_IMPLICIT_FALLTHROUGH="-Wimplic
CONFIG_GCC10_NO_ARRAY_BOUNDS=y
CONFIG_GCC_NO_STRINGOP_OVERFLOW=y
CONFIG_ARCH_SUPPORTS_INT128=y
-CONFIG_NUMA_BALANCING=y
-CONFIG_NUMA_BALANCING_DEFAULT_ENABLED=y
CONFIG_SLAB_OBJ_EXT=y
CONFIG_CGROUPS=y
CONFIG_PAGE_COUNTER=y
@@ -933,14 +936,12 @@ CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PU
CONFIG_HAVE_ARCH_HUGE_VMAP=y
CONFIG_HAVE_ARCH_HUGE_VMALLOC=y
CONFIG_ARCH_WANT_HUGE_PMD_SHARE=y
-CONFIG_ARCH_WANT_PMD_MKWRITE=y
CONFIG_HAVE_ARCH_SOFT_DIRTY=y
CONFIG_HAVE_MOD_ARCH_SPECIFIC=y
CONFIG_MODULES_USE_ELF_RELA=y
CONFIG_ARCH_HAS_EXECMEM_ROX=y
CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK=y
CONFIG_HAVE_SOFTIRQ_ON_OWN_STACK=y
-CONFIG_SOFTIRQ_ON_OWN_STACK=y
CONFIG_ARCH_HAS_ELF_RANDOMIZE=y
CONFIG_HAVE_ARCH_MMAP_RND_BITS=y
CONFIG_HAVE_EXIT_THREAD=y
@@ -1101,7 +1102,6 @@ CONFIG_LOCK_SPIN_ON_OWNER=y
CONFIG_ARCH_USE_QUEUED_SPINLOCKS=y
CONFIG_QUEUED_SPINLOCKS=y
CONFIG_ARCH_USE_QUEUED_RWLOCKS=y
-CONFIG_QUEUED_RWLOCKS=y
CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE=y
CONFIG_ARCH_HAS_SYNC_CORE_BEFORE_USERMODE=y
CONFIG_ARCH_HAS_SYSCALL_WRAPPER=y
@@ -1191,12 +1191,11 @@ CONFIG_SPLIT_PMD_PTLOCKS=y
CONFIG_BALLOON=y
CONFIG_BALLOON_MIGRATION=y
CONFIG_COMPACTION=y
-CONFIG_COMPACT_UNEVICTABLE_DEFAULT=1
+CONFIG_COMPACT_UNEVICTABLE_DEFAULT=0
CONFIG_PAGE_REPORTING=y
CONFIG_MIGRATION=y
CONFIG_DEVICE_MIGRATION=y
CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION=y
-CONFIG_ARCH_ENABLE_THP_MIGRATION=y
CONFIG_CONTIG_ALLOC=y
CONFIG_PCP_BATCH_SCALE_MAX=5
CONFIG_PHYS_ADDR_T_64BIT=y
@@ -1208,30 +1207,10 @@ CONFIG_MEMORY_FAILURE=y
CONFIG_HWPOISON_INJECT=m
CONFIG_ARCH_WANT_GENERAL_HUGETLB=y
CONFIG_ARCH_WANTS_THP_SWAP=y
-# CONFIG_PERSISTENT_HUGE_ZERO_FOLIO is not set
-CONFIG_MM_ID=y
-CONFIG_TRANSPARENT_HUGEPAGE=y
-CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS=y
-# CONFIG_TRANSPARENT_HUGEPAGE_MADVISE is not set
-# CONFIG_TRANSPARENT_HUGEPAGE_NEVER is not set
-CONFIG_TRANSPARENT_HUGEPAGE_SHMEM_HUGE_NEVER=y
-# CONFIG_TRANSPARENT_HUGEPAGE_SHMEM_HUGE_ALWAYS is not set
-# CONFIG_TRANSPARENT_HUGEPAGE_SHMEM_HUGE_WITHIN_SIZE is not set
-# CONFIG_TRANSPARENT_HUGEPAGE_SHMEM_HUGE_ADVISE is not set
-CONFIG_TRANSPARENT_HUGEPAGE_TMPFS_HUGE_NEVER=y
-# CONFIG_TRANSPARENT_HUGEPAGE_TMPFS_HUGE_ALWAYS is not set
-# CONFIG_TRANSPARENT_HUGEPAGE_TMPFS_HUGE_WITHIN_SIZE is not set
-# CONFIG_TRANSPARENT_HUGEPAGE_TMPFS_HUGE_ADVISE is not set
-CONFIG_THP_SWAP=y
-# CONFIG_READ_ONLY_THP_FOR_FS is not set
-# CONFIG_NO_PAGE_MAPCOUNT is not set
CONFIG_PAGE_MAPCOUNT=y
CONFIG_PGTABLE_HAS_HUGE_LEAVES=y
CONFIG_HAVE_GIGANTIC_FOLIOS=y
CONFIG_ASYNC_KERNEL_PGTABLE_FREE=y
-CONFIG_ARCH_SUPPORTS_HUGE_PFNMAP=y
-CONFIG_ARCH_SUPPORTS_PMD_PFNMAP=y
-CONFIG_ARCH_SUPPORTS_PUD_PFNMAP=y
CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK=y
CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK=y
CONFIG_USE_PERCPU_NUMA_NODE_ID=y
@@ -1537,7 +1516,6 @@ CONFIG_NF_FLOW_TABLE_INET=m
CONFIG_NF_FLOW_TABLE=m
CONFIG_NF_FLOW_TABLE_PROCFS=y
CONFIG_NETFILTER_XTABLES=y
-# CONFIG_NETFILTER_XTABLES_LEGACY is not set

#
# Xtables combined modules
@@ -2859,7 +2837,6 @@ CONFIG_DM_INTEGRITY=m
# CONFIG_DM_ZONED is not set
CONFIG_DM_AUDIT=y
# CONFIG_DM_VDO is not set
-# CONFIG_DM_PCACHE is not set
CONFIG_TARGET_CORE=m
CONFIG_TCM_IBLOCK=m
CONFIG_TCM_FILEIO=m
@@ -5344,6 +5321,7 @@ CONFIG_DRM_I915_MAX_REQUEST_BUSYWAIT=800
CONFIG_DRM_I915_STOP_TIMEOUT=100
CONFIG_DRM_I915_TIMESLICE_DURATION=1
CONFIG_DRM_MGAG200=m
+# CONFIG_DRM_MGAG200_DISABLE_WRITECOMBINE is not set
CONFIG_DRM_NOUVEAU=m
CONFIG_NOUVEAU_DEBUG=5
CONFIG_NOUVEAU_DEBUG_DEFAULT=3
@@ -6939,7 +6917,6 @@ CONFIG_LEDS_TRIGGER_DISK=y
# CONFIG_LEDS_TRIGGER_MTD is not set
CONFIG_LEDS_TRIGGER_HEARTBEAT=m
CONFIG_LEDS_TRIGGER_BACKLIGHT=m
-# CONFIG_LEDS_TRIGGER_CPU is not set
# CONFIG_LEDS_TRIGGER_ACTIVITY is not set
CONFIG_LEDS_TRIGGER_GPIO=m
CONFIG_LEDS_TRIGGER_DEFAULT_ON=m
@@ -8387,12 +8364,8 @@ CONFIG_RAMDAX=m
CONFIG_NVDIMM_KEYS=y
# CONFIG_NVDIMM_SECURITY_TEST is not set
CONFIG_DAX=y
-CONFIG_DEV_DAX=m
-CONFIG_DEV_DAX_PMEM=m
CONFIG_DEV_DAX_HMEM=m
-CONFIG_DEV_DAX_CXL=m
CONFIG_DEV_DAX_HMEM_DEVICES=y
-CONFIG_DEV_DAX_KMEM=m
CONFIG_NVMEM=y
CONFIG_NVMEM_SYSFS=y
# CONFIG_NVMEM_LAYOUTS is not set
@@ -8476,7 +8449,6 @@ CONFIG_GFS2_FS_LOCKING_DLM=y
# CONFIG_F2FS_FS is not set
# CONFIG_ZONEFS_FS is not set
CONFIG_FS_DAX=y
-CONFIG_FS_DAX_PMD=y
CONFIG_FS_POSIX_ACL=y
CONFIG_EXPORTFS=y
CONFIG_EXPORTFS_BLOCK_OPS=y
@@ -9490,7 +9462,6 @@ CONFIG_HAVE_ARCH_KFENCE=y
# CONFIG_KFENCE is not set
CONFIG_HAVE_ARCH_KMSAN=y
CONFIG_HAVE_KMSAN_COMPILER=y
-# CONFIG_KMSAN is not set
# end of Memory Debugging

CONFIG_DEBUG_SHIRQ=y
@@ -9516,7 +9487,6 @@ CONFIG_BOOTPARAM_HARDLOCKUP_PANIC=y
CONFIG_DETECT_HUNG_TASK=y
CONFIG_DEFAULT_HUNG_TASK_TIMEOUT=480
CONFIG_BOOTPARAM_HUNG_TASK_PANIC=0
-CONFIG_DETECT_HUNG_TASK_BLOCKER=y
CONFIG_WQ_WATCHDOG=y
CONFIG_BOOTPARAM_WQ_STALL_PANIC=0
# CONFIG_WQ_CPU_INTENSIVE_REPORT is not set
@@ -9541,9 +9511,7 @@ CONFIG_LOCK_DEBUGGING_SUPPORT=y
# CONFIG_LOCK_STAT is not set
# CONFIG_DEBUG_RT_MUTEXES is not set
# CONFIG_DEBUG_SPINLOCK is not set
-# CONFIG_DEBUG_MUTEXES is not set
# CONFIG_DEBUG_WW_MUTEX_SLOWPATH is not set
-# CONFIG_DEBUG_RWSEMS is not set
# CONFIG_DEBUG_LOCK_ALLOC is not set
CONFIG_DEBUG_ATOMIC_SLEEP=y
# CONFIG_DEBUG_LOCKING_API_SELFTESTS is not set
@@ -9882,7 +9850,6 @@ CONFIG_SIPHASH_KUNIT_TEST=m
# CONFIG_TEST_MEMCAT_P is not set
# CONFIG_TEST_OBJAGG is not set
# CONFIG_TEST_MEMINIT is not set
-CONFIG_TEST_HMM=m
# CONFIG_TEST_FREE_PAGES is not set
# CONFIG_TEST_FPU is not set
# CONFIG_TEST_CLOCKSOURCE_WATCHDOG is not set

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki