Re: [PATCH v7 24/26] PREEMPT_RT injection

kernel test robot
2026-03-13T09:36:41Z

Hello,

we made a similar report two weeks ago. again, 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 commit (previous patch) now fails
persistently.

=========================================================================================
tbox_group/testcase/rootfs/kconfig/compiler/sleep:
vm-snb/boot/debian-13-x86_64-20250902.cgz/x86_64-rhel-9.4/gcc-14/1

24a93cdeef1153e2 20d2f07d259d55c5b2f1e8c97da
---------------- ---------------------------
fail:runs %reproduction fail:runs
| | |
:6 100% 6:6 dmesg.BUG:kernel_reboot-without-warning_in_test_stage
:6 100% 6:6 dmesg.boot_failures

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: 20d2f07d259d55c5b2f1e8c97daa270b48b8554e ("[PATCH v7 24/26] 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/20260310-205630
base: https://gitlab.freedesktop.org/drm/i915/kernel.git for-linux-next
patch link: https://lore.kernel.org/all/20260310115709.2276203-25-dev@lankhorst.se/
patch subject: [PATCH v7 24/26] PREEMPT_RT injection

in testcase: boot

config: x86_64-rhel-9.4
compiler: gcc-14
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@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202603131728.1fedee25-lkp@intel.com

[ 12.960487][ T186] scsi 1:0:0:0: Attached scsi generic sg0 type 5
[ 12.985908][ T186] sr 1:0:0:0: [sr0] scsi3-mmc drive: 4x/4x cd/rw xa/form2 tray
[ 12.985917][ T186] cdrom: Uniform CD-ROM driver Revision: 3.20
[ 13.001113][ T186] sr 1:0:0:0: Attached scsi CD-ROM sr0
LKP: ttyS0: 213: LKP: tbox cant kexec and rebooting forcely
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/20260313/202603131728.1fedee25-lkp@intel.com

[1]
--- /pkg/linux/x86_64-rhel-9.4/gcc-14/24a93cdeef1153e28b6157b6fd805b02ca23dd64/.config 2026-03-12 11:30:32.108505780 +0800
+++ /pkg/linux/x86_64-rhel-9.4/gcc-14/20d2f07d259d55c5b2f1e8c97daa270b48b8554e/.config 2026-03-12 12:24:04.187019016 +0800
@@ -131,7 +131,8 @@ CONFIG_PREEMPT_BUILD=y
CONFIG_ARCH_HAS_PREEMPT_LAZY=y
# CONFIG_PREEMPT is not set
CONFIG_PREEMPT_LAZY=y
-# CONFIG_PREEMPT_RT is not set
+CONFIG_PREEMPT_RT=y
+# CONFIG_PREEMPT_RT_NEEDS_BH_LOCK is not set
CONFIG_PREEMPT_COUNT=y
CONFIG_PREEMPTION=y
# CONFIG_PREEMPT_DYNAMIC is not set
@@ -160,6 +161,7 @@ CONFIG_CPU_ISOLATION=y
# RCU Subsystem
#
CONFIG_TREE_RCU=y
+CONFIG_PREEMPT_RCU=y
# CONFIG_RCU_EXPERT is not set
CONFIG_TREE_SRCU=y
CONFIG_TASKS_RCU_GENERIC=y
@@ -169,8 +171,11 @@ 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

@@ -186,7 +191,6 @@ CONFIG_HAVE_UNSTABLE_SCHED_CLOCK=y
# Scheduler features
#
# CONFIG_UCLAMP_TASK is not set
-# CONFIG_SCHED_PROXY_EXEC is not set
# end of Scheduler features

CONFIG_ARCH_SUPPORTS_NUMA_BALANCING=y
@@ -198,8 +202,6 @@ CONFIG_CC_NO_ARRAY_BOUNDS=y
CONFIG_GCC_NO_STRINGOP_OVERFLOW=y
CONFIG_CC_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
@@ -928,14 +930,12 @@ 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
@@ -1100,7 +1100,6 @@ 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
@@ -1189,12 +1188,11 @@ 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
@@ -1206,30 +1204,10 @@ 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
@@ -1531,7 +1509,6 @@ 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
@@ -2842,7 +2819,6 @@ 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
@@ -5412,7 +5388,6 @@ CONFIG_DRM_I915_DP_TUNNEL=y
# CONFIG_DRM_I915_DEBUG_GUC is not set
# CONFIG_DRM_I915_SELFTEST is not set
# CONFIG_DRM_I915_LOW_LEVEL_TRACEPOINTS is not set
-# CONFIG_DRM_I915_DEBUG_VBLANK_EVADE is not set
# CONFIG_DRM_I915_DEBUG_RUNTIME_PM is not set
# CONFIG_DRM_I915_DEBUG_WAKEREF is not set
# end of drm/i915 Debugging
@@ -5432,6 +5407,7 @@ CONFIG_DRM_I915_TIMESLICE_DURATION=1
# end of drm/i915 Profile Guided Optimisation

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
@@ -7014,7 +6990,6 @@ 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
@@ -8441,12 +8416,8 @@ 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
@@ -8543,7 +8514,6 @@ CONFIG_F2FS_IOSTAT=y
# CONFIG_F2FS_UNFAIR_RWSEM 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
@@ -9571,7 +9541,6 @@ 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
@@ -9596,9 +9565,7 @@ 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 is not set
# CONFIG_DEBUG_LOCKING_API_SELFTESTS is not set

--
0-DAY CI Kernel Test Service