[LTP] [paulmckrcu:dev.2026.05.07a] [rcutorture] c2e6a63ac1: RIP:rcu_torture_irq[rcutorture]
Paul E. McKenney
paulmck@kernel.org
Thu May 21 17:55:53 CEST 2026
On Thu, May 21, 2026 at 03:54:05PM +0800, kernel test robot wrote:
>
> hi, Paul,
>
> below report is just FYI. if the issue is soloved on newer branched, please just
> ignore. thanks
>
>
> Hello,
>
>
> kernel test robot noticed "RIP:rcu_torture_irq[rcutorture]" on:
>
> commit: c2e6a63ac168107454d5fe595c1213e5760d642f ("rcutorture: Test RCU readers from hardware interrupt handlers")
> https://github.com/paulmckrcu/linux dev.2026.05.07a
>
> in testcase: ltp
> version:
> with following parameters:
>
> test: kernel_misc
>
>
>
> config: x86_64-rhel-9.4-ltp
> compiler: gcc-14
> test machine: 8 threads 1 sockets Intel(R) Core(TM) i7-4790T CPU @ 2.70GHz (Haswell) with 16G memory
>
> (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/202605211529.6ba1b4ff-lkp@intel.com
This should be fixed in branch dev.2026.05.19a. The problem was that
I forgot that smp_call_function_single() handlers can be invoked from
the idle loop instead of from an actual hardware interrupt handler.
The devil truly is in the details! ;-)
Thanx, Paul
> kern :warn : [ 434.509085] [ T5907] ------------[ cut here ]------------
> kern :warn : [ 434.509089] [ T5907] WARNING: kernel/rcu/rcutorture.c:2653 at rcu_torture_irq+0x119/0x170 [rcutorture], CPU#2: rcu_torture_rea/5907
> kern :warn : [ 434.509137] [ T5907] Modules linked in: rcutorture(+) torture netconsole binfmt_misc snd_hda_codec_intelhdmi snd_hda_codec_hdmi btrfs libblake2b zstd_compress raid6_pq intel_rapl_msr intel_rapl_common xor snd_hda_codec_alc882 x86_pkg_temp_thermal snd_hda_codec_realtek_lib i915 snd_hda_codec_generic intel_powerclamp sd_mod coretemp snd_hda_intel intel_gtt drm_buddy sg snd_hda_codec ttm kvm_intel snd_soc_rt5640 drm_display_helper snd_soc_rl6231 snd_hda_core regmap_i2c kvm snd_intel_dspcfg cec snd_soc_core snd_intel_sdw_acpi drm_client_lib snd_hwdep snd_compress irqbypass drm_kms_helper rapl mxm_wmi ahci snd_pcm libahci alx video intel_cstate intel_uncore pcspkr mei_me i2c_i801 libata mdio snd_timer mei i2c_smbus lpc_ich snd wmi soundcore acpi_pad joydev drm fuse nfnetlink [last unloaded: ltp_uaccess(OE)]
> kern :warn : [ 434.509249] [ T5907] CPU: 2 UID: 0 PID: 5907 Comm: rcu_torture_rea Tainted: G S W OE 7.1.0-rc1+ #1 PREEMPT(lazy)
> kern :warn : [ 434.509265] [ T5907] Tainted: [S]=CPU_OUT_OF_SPEC, [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
> kern :warn : [ 434.509267] [ T5907] Hardware name: Gigabyte Technology Co., Ltd. Z97X-UD5H/Z97X-UD5H, BIOS F9 04/21/2015
> kern :warn : [ 434.509270] [ T5907] RIP: 0010:rcu_torture_irq (rcu/rcutorture.c:2654 (discriminator 1)) rcutorture
> kern :warn : [ 434.509287] [ T5907] Code: 93 20 01 00 00 48 83 c4 08 48 c7 c6 10 bb 19 c1 48 89 c7 5b e9 68 14 f7 c2 48 83 c4 08 5b c3 cc cc cc cc 0f 0b e9 0e ff ff ff <0f> 0b e9 fc fe ff ff e8 5b 00 da c0 e9 5a ff ff ff 48 89 04 24 e8
> All code
> ========
> 0: 93 xchg %eax,%ebx
> 1: 20 01 and %al,(%rcx)
> 3: 00 00 add %al,(%rax)
> 5: 48 83 c4 08 add $0x8,%rsp
> 9: 48 c7 c6 10 bb 19 c1 mov $0xffffffffc119bb10,%rsi
> 10: 48 89 c7 mov %rax,%rdi
> 13: 5b pop %rbx
> 14: e9 68 14 f7 c2 jmp 0xffffffffc2f71481
> 19: 48 83 c4 08 add $0x8,%rsp
> 1d: 5b pop %rbx
> 1e: c3 ret
> 1f: cc int3
> 20: cc int3
> 21: cc int3
> 22: cc int3
> 23: 0f 0b ud2
> 25: e9 0e ff ff ff jmp 0xffffffffffffff38
> 2a:* 0f 0b ud2 <-- trapping instruction
> 2c: e9 fc fe ff ff jmp 0xffffffffffffff2d
> 31: e8 5b 00 da c0 call 0xffffffffc0da0091
> 36: e9 5a ff ff ff jmp 0xffffffffffffff95
> 3b: 48 89 04 24 mov %rax,(%rsp)
> 3f: e8 .byte 0xe8
>
> Code starting with the faulting instruction
> ===========================================
> 0: 0f 0b ud2
> 2: e9 fc fe ff ff jmp 0xffffffffffffff03
> 7: e8 5b 00 da c0 call 0xffffffffc0da0067
> c: e9 5a ff ff ff jmp 0xffffffffffffff6b
> 11: 48 89 04 24 mov %rax,(%rsp)
> 15: e8 .byte 0xe8
> kern :warn : [ 434.509290] [ T5907] RSP: 0018:ffffc9000261fc10 EFLAGS: 00010046
> kern :warn : [ 434.509294] [ T5907] RAX: 0000000080000002 RBX: ffff888396343248 RCX: ffffffff81828b23
> kern :warn : [ 434.509297] [ T5907] RDX: 0000000000000000 RSI: ffff888396343240 RDI: 0000000000000000
> kern :warn : [ 434.509299] [ T5907] RBP: 0000000000000246 R08: 0000000000000000 R09: fffffbfff0c72894
> kern :warn : [ 434.509301] [ T5907] R10: ffffffff863944a7 R11: 0000000000000000 R12: ffffffffc11a3f10
> kern :warn : [ 434.509303] [ T5907] R13: 0000000000000000 R14: ffffffffc11a3f10 R15: 0000000000000000
> kern :warn : [ 434.509316] [ T5907] FS: 0000000000000000(0000) GS:ffff88840ef63000(0000) knlGS:0000000000000000
> kern :warn : [ 434.509318] [ T5907] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> kern :warn : [ 434.509320] [ T5907] CR2: 000056053f590492 CR3: 000000041c870005 CR4: 00000000001726f0
> kern :warn : [ 434.509323] [ T5907] Call Trace:
> kern :warn : [ 434.509325] [ T5907] <TASK>
> kern :warn : [ 434.509327] [ T5907] generic_exec_single (smp.c:136 smp.c:453)
> kern :warn : [ 434.509332] [ T5907] ? __pfx_rcu_torture_irq (rcu/rcutorture.c:2607) rcutorture
> kern :warn : [ 434.509360] [ T5907] smp_call_function_single (smp.c:699)
> kern :warn : [ 434.509364] [ T5907] ? __pfx_smp_call_function_single (smp.c:375 (discriminator 4))
> kern :warn : [ 434.509367] [ T5907] ? local_clock_noinstr (sched/clock.c:307)
> kern :warn : [ 434.509371] [ T5907] rcu_torture_reader (rcu/rcutorture.c:2700) rcutorture
> kern :warn : [ 434.509398] [ T5907] ? __pfx_rcu_torture_reader (rcu/rcutorture.c:4041) rcutorture
> kern :warn : [ 434.509412] [ T5907] ? _raw_spin_lock_irqsave (linux/instrumented.h:55 linux/atomic/atomic-instrumented.h:1301 asm-generic/qspinlock.h:111 linux/spinlock.h:187 linux/spinlock_api_smp.h:133 locking/spinlock.c:166)
> kern :warn : [ 434.509417] [ T5907] ? __pfx_rcu_torture_timer (linux/slab.h:950) rcutorture
> kern :warn : [ 434.509443] [ T5907] ? __kthread_parkme (linux/instrumented.h:82 asm-generic/bitops/instrumented-non-atomic.h:141 kthread.c:272)
> kern :warn : [ 434.509448] [ T5907] ? __pfx_rcu_torture_reader (rcu/rcutorture.c:4041) rcutorture
> kern :warn : [ 434.509465] [ T5907] ? __pfx_rcu_torture_reader (rcu/rcutorture.c:4041) rcutorture
> kern :warn : [ 434.509490] [ T5907] kthread (kthread.c:436)
> kern :warn : [ 434.509493] [ T5907] ? recalc_sigpending (linux/instrumented.h:97 asm-generic/bitops/instrumented-atomic.h:41 linux/thread_info.h:109 signal.c:181)
> kern :warn : [ 434.509495] [ T5907] ? __pfx_kthread (linux/list.h:381 (discriminator 2))
> kern :warn : [ 434.509498] [ T5907] ret_from_fork (x86/kernel/process.c:158)
> kern :warn : [ 434.509502] [ T5907] ? __pfx_ret_from_fork (x86/include/asm/entry-common.h:54)
> kern :warn : [ 434.509504] [ T5907] ? switch_fpu (linux/instrumented.h:82 asm-generic/bitops/instrumented-non-atomic.h:141 linux/thread_info.h:133 linux/sched.h:2067 x86/include/asm/fpu/sched.h:34)
> kern :warn : [ 434.509508] [ T5907] ? __switch_to (x86/kernel/process_64.c:403 x86/kernel/process_64.c:663)
> kern :warn : [ 434.509511] [ T5907] ? __switch_to_asm (x86/entry/entry_64.S:206)
> kern :warn : [ 434.509515] [ T5907] ? __pfx_kthread (linux/list.h:381 (discriminator 2))
> kern :warn : [ 434.509517] [ T5907] ret_from_fork_asm (x86/entry/entry_64.S:245)
> kern :warn : [ 434.509522] [ T5907] </TASK>
> kern :warn : [ 434.509523] [ T5907] ---[ end trace 0000000000000000 ]---
>
>
> The kernel config and materials to reproduce are available at:
> https://download.01.org/0day-ci/archive/20260521/202605211529.6ba1b4ff-lkp@intel.com
>
>
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki
>
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