Regressions on arm64 devices and qemu-arm64 while running LTP controllers and selftests cgroup test cases the following kernel Panic Internal error oops found on the Linux next-20250623 tag.

Regressions found on arm64 device - Kernel Panic Internal oops @ LTP controllers - Kernel Panic Internal oops @ selftest cgroups

Test environments: - Dragonboard-410c - e850-96 - FVP - Juno-r2 - rk3399-rock-pi-4b - qemu-arm64

Regression Analysis: - New regression? Yes - Reproducibility? Yes

Boot regression: arm64 devices kernel panic Internal error Oops at pidfs_free_pid (fs/pidfs.c:162)

Reported-by: Linux Kernel Functional Testing lkft@linaro.org

## Test log [ 67.087303] Internal error: Oops: 0000000096000004 [#1] SMP [ 67.094021] Modules linked in: snd_soc_hdmi_codec venus_enc venus_dec videobuf2_dma_contig pm8916_wdt qcom_wcnss_pil coresight_cpu_debug coresight_tmc coresight_replicator qcom_camss coresight_stm snd_soc_lpass_apq8016 msm qrtr coresight_funnel snd_soc_msm8916_digital snd_soc_lpass_cpu coresight_tpiu snd_soc_msm8916_analog videobuf2_dma_sg stm_core coresight_cti snd_soc_lpass_platform snd_soc_apq8016_sbc venus_core snd_soc_qcom_common qcom_q6v5_mss v4l2_fwnode coresight snd_soc_core qcom_pil_info v4l2_async snd_compress llcc_qcom snd_pcm_dmaengine ocmem qcom_q6v5 v4l2_mem2mem videobuf2_memops snd_pcm qcom_sysmon drm_exec adv7511 snd_timer videobuf2_v4l2 gpu_sched qcom_common snd videodev drm_dp_aux_bus qcom_glink_smem soundcore qcom_spmi_vadc mdt_loader drm_display_helper qnoc_msm8916 qmi_helpers videobuf2_common qcom_vadc_common qcom_spmi_temp_alarm rtc_pm8xxx qcom_pon qcom_stats mc cec drm_client_lib qcom_rng rpmsg_ctrl display_connector rpmsg_char phy_qcom_usb_hs socinfo drm_kms_helper rmtfs_mem ramoops [ 67.094437] reed_solomon fuse drm backlight ip_tables x_tables [ 67.189084] CPU: 3 UID: 0 PID: 0 Comm: swapper/3 Not tainted 6.16.0-rc3-next-20250623 #1 PREEMPT [ 67.194810] Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT) [ 67.234078] pc : pidfs_free_pid (fs/pidfs.c:162) [ 67.236989] lr : put_pid.part.0 (kernel/pid.c:104) [ 67.239958] sp : ffff80008001be50 [ 67.243892] x29: ffff80008001be50 x28: ffff800082288180 x27: ffff8000801c7654 [ 67.247206] x26: ffff8000822882c0 x25: 000000000000000a x24: ffff00003fc96940 [ 67.254295] x23: 0000000000000000 x22: 000000000000003f x21: ffff00003fc968c0 [ 67.261410] x20: ffff800082212740 x19: 0000000000000000 x18: ffff8000875abc00 [ 67.268490] x17: ffff7fffbdb7b000 x16: ffff800080018000 x15: 010c194d58e3a052 [ 67.275644] x14: 0000000000000000 x13: 0000000000000000 x12: 00000000000003d4 [ 67.282785] x11: 0000000000000000 x10: 000000000000003f x9 : ffff00000295a500 [ 67.289863] x8 : ffff80008001be30 x7 : 0000000000000000 x6 : ffff00003fc99be0 [ 67.296923] x5 : ffff8000811fafe8 x4 : 0000000000100004 x3 : 0000000000000000 [ 67.304036] x2 : 0000000000000000 x1 : 0000000000000001 x0 : ffff00000487a9c0 [ 67.311148] Call trace: [ 67.318222] pidfs_free_pid (fs/pidfs.c:162) (P) [ 67.320916] put_pid.part.0 (kernel/pid.c:104) [ 67.324597] delayed_put_pid (kernel/pid.c:114) [ 67.328231] rcu_core (arch/arm64/include/asm/preempt.h:13 (discriminator 1) kernel/rcu/tree.c:2589 (discriminator 1) kernel/rcu/tree.c:2838 (discriminator 1)) [ 67.331859] rcu_core_si (kernel/rcu/tree.c:2856) [ 67.335210] handle_softirqs (arch/arm64/include/asm/preempt.h:13 (discriminator 1) kernel/softirq.c:581 (discriminator 1)) [ 67.338511] __do_softirq (kernel/softirq.c:614) [ 67.342526] ____do_softirq (arch/arm64/kernel/irq.c:82) [ 67.345735] call_on_irq_stack (arch/arm64/kernel/entry.S:897) [ 67.349550] do_softirq_own_stack (arch/arm64/kernel/irq.c:87) [ 67.353544] __irq_exit_rcu (kernel/softirq.c:460 kernel/softirq.c:680) [ 67.357431] irq_exit_rcu (kernel/softirq.c:699) [ 67.361234] el1_interrupt (arch/arm64/include/asm/current.h:19 arch/arm64/kernel/entry-common.c:280 arch/arm64/kernel/entry-common.c:586 arch/arm64/kernel/entry-common.c:598) [ 67.364591] el1h_64_irq_handler (arch/arm64/kernel/entry-common.c:604) [ 67.368381] el1h_64_irq (arch/arm64/kernel/entry.S:596) [ 67.372250] cpuidle_enter_state (drivers/cpuidle/cpuidle.c:292) (P) [ 67.375640] cpuidle_enter (drivers/cpuidle/cpuidle.c:391 (discriminator 2)) [ 67.380025] do_idle (kernel/sched/idle.c:160 kernel/sched/idle.c:235 kernel/sched/idle.c:330) [ 67.383811] cpu_startup_entry (kernel/sched/idle.c:428 (discriminator 1)) [ 67.387062] secondary_start_kernel (arch/arm64/include/asm/atomic_ll_sc.h:95 (discriminator 2) arch/arm64/include/asm/atomic.h:28 (discriminator 2) include/linux/atomic/atomic-arch-fallback.h:546 (discriminator 2) include/linux/atomic/atomic-arch-fallback.h:994 (discriminator 2) include/linux/atomic/atomic-instrumented.h:436 (discriminator 2) include/linux/sched/mm.h:37 (discriminator 2) arch/arm64/kernel/smp.c:214 (discriminator 2)) [ 67.390956] __secondary_switched (arch/arm64/kernel/head.S:405) [ 67.395181] Code: f9401c13 f9001c1f b140067f 540001a8 (f9400274) All code ======== 0: f9401c13 ldr x19, [x0, #56] 4: f9001c1f str xzr, [x0, #56] 8: b140067f cmn x19, #0x1, lsl #12 c: 540001a8 b.hi 0x40 // b.pmore 10:* f9400274 ldr x20, [x19] <-- trapping instruction

Code starting with the faulting instruction =========================================== 0: f9400274 ldr x20, [x19] [ 67.399334] ---[ end trace 0000000000000000 ]---

## Source * Kernel version: 6.16.0-rc3-next-20250623 * Git tree: https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next.git * Git sha: f817b6dd2b62d921a6cdc0a3ac599cd1851f343c * Git describe: next-20250623 * Project details: https://regressions.linaro.org/lkft/linux-next-master/next-20250623/ * Architectures: arm64 * Toolchains: gcc-13 * Kconfigs: defconfig+selftest/configs

## Build arm64 * Test log: https://qa-reports.linaro.org/api/testruns/28834568/log_file/ * Test Lava log: https://lkft.validation.linaro.org/scheduler/job/8326000#L2426 * Test Lava log 2: https://lkft.validation.linaro.org/scheduler/job/8326094#L5378 * Test details: https://regressions.linaro.org/lkft/linux-next-master/next-20250623/log-pars... * Build link: https://storage.tuxsuite.com/public/linaro/lkft/builds/2ytmpuyjaGkw1YlPt0MbP... * Kernel config: https://storage.tuxsuite.com/public/linaro/lkft/builds/2ytmpuyjaGkw1YlPt0MbP...

-- Linaro LKFT https://lkft.linaro.org