Hello, kernel test robot noticed "WARNING:at_kernel/hazptr.c:#hazptr_scan" on: commit: c1508707268498a6fd3ca5853ad65f9482c12374 ("[RFC PATCH v3 4/4] sched+mm: Use hazard pointers to track lazy active mm existence") url: https://github.com/intel-lab-lkp/linux/commits/Mathieu-Desnoyers/compiler-h-Introduce-ptr_eq-to-preserve-address-dependency/20241008-215353 base: https://git.kernel.org/cgit/linux/kernel/git/powerpc/linux.git next patch link: https://lore.kernel.org/all/20241008135034.1982519-5-mathieu.desnoyers@xxxxxxxxxxxx/ patch subject: [RFC PATCH v3 4/4] sched+mm: Use hazard pointers to track lazy active mm existence in testcase: boot config: i386-randconfig-013-20241011 compiler: gcc-12 test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G (please refer to attached dmesg/kmsg for entire log/backtrace) +-----------------------------------------+------------+------------+ | | b62696cacd | c150870726 | +-----------------------------------------+------------+------------+ | WARNING:at_kernel/hazptr.c:#hazptr_scan | 0 | 5 | | EIP:hazptr_scan | 0 | 5 | +-----------------------------------------+------------+------------+ 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/202410141617.612a0f5b-lkp@xxxxxxxxx [ 6.951355][ T22] ------------[ cut here ]------------ [ 6.951920][ T22] WARNING: CPU: 0 PID: 22 at kernel/hazptr.c:28 hazptr_scan (kernel/hazptr.c:28) [ 6.952580][ T22] Modules linked in: [ 6.952880][ T22] CPU: 0 UID: 0 PID: 22 Comm: khugepaged Not tainted 6.12.0-rc1-00004-gc15087072684 #10 [ 6.953685][ T22] EIP: hazptr_scan (kernel/hazptr.c:28) [ 6.954087][ T22] Code: c0 74 0a 85 db 8b 0a 74 45 39 c8 74 21 5b 5e 5d 31 c0 31 d2 31 c9 c3 8d b4 26 00 00 00 00 f7 05 a4 18 34 c3 ff ff ff 7f 74 14 <0f> 0b eb d1 89 c1 31 c0 ff d3 5b 5e 5d 31 c0 31 d2 31 c9 c3 8b 0d All code ======== 0: c0 74 0a 85 db shlb $0xdb,-0x7b(%rdx,%rcx,1) 5: 8b 0a mov (%rdx),%ecx 7: 74 45 je 0x4e 9: 39 c8 cmp %ecx,%eax b: 74 21 je 0x2e d: 5b pop %rbx e: 5e pop %rsi f: 5d pop %rbp 10: 31 c0 xor %eax,%eax 12: 31 d2 xor %edx,%edx 14: 31 c9 xor %ecx,%ecx 16: c3 ret 17: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 1e: f7 05 a4 18 34 c3 ff testl $0x7fffffff,-0x3ccbe75c(%rip) # 0xffffffffc33418cc 25: ff ff 7f 28: 74 14 je 0x3e 2a:* 0f 0b ud2 <-- trapping instruction 2c: eb d1 jmp 0xffffffffffffffff 2e: 89 c1 mov %eax,%ecx 30: 31 c0 xor %eax,%eax 32: ff d3 call *%rbx 34: 5b pop %rbx 35: 5e pop %rsi 36: 5d pop %rbp 37: 31 c0 xor %eax,%eax 39: 31 d2 xor %edx,%edx 3b: 31 c9 xor %ecx,%ecx 3d: c3 ret 3e: 8b .byte 0x8b 3f: 0d .byte 0xd Code starting with the faulting instruction =========================================== 0: 0f 0b ud2 2: eb d1 jmp 0xffffffffffffffd5 4: 89 c1 mov %eax,%ecx 6: 31 c0 xor %eax,%eax 8: ff d3 call *%rbx a: 5b pop %rbx b: 5e pop %rsi c: 5d pop %rbp d: 31 c0 xor %eax,%eax f: 31 d2 xor %edx,%edx 11: 31 c9 xor %ecx,%ecx 13: c3 ret 14: 8b .byte 0x8b 15: 0d .byte 0xd [ 6.955564][ T22] EAX: c6087680 EBX: c1061470 ECX: 00000000 EDX: c2e104e8 [ 6.956135][ T22] ESI: c2e104e4 EDI: 00000001 EBP: c42ade88 ESP: c42ade80 [ 6.956665][ T22] DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 EFLAGS: 00010202 [ 6.957266][ T22] CR0: 80050033 CR2: 0819cd10 CR3: 04033d80 CR4: 000406b0 [ 6.957807][ T22] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 6.958380][ T22] DR6: fffe0ff0 DR7: 00000400 [ 6.958747][ T22] Call Trace: [ 6.959005][ T22] ? show_regs (arch/x86/kernel/dumpstack.c:479) [ 6.959362][ T22] ? hazptr_scan (kernel/hazptr.c:28) [ 6.959694][ T22] ? __warn (kernel/panic.c:748) [ 6.959974][ T22] ? hazptr_scan (kernel/hazptr.c:28) [ 6.960361][ T22] ? hazptr_scan (kernel/hazptr.c:28) [ 6.960695][ T22] ? report_bug (lib/bug.c:180 lib/bug.c:219) [ 6.961083][ T22] ? hazptr_scan (kernel/hazptr.c:28) [ 6.961427][ T22] ? exc_overflow (arch/x86/kernel/traps.c:301) [ 6.961778][ T22] ? handle_bug (arch/x86/kernel/traps.c:260) [ 6.962157][ T22] ? exc_invalid_op (arch/x86/kernel/traps.c:309 (discriminator 1)) [ 6.962549][ T22] ? thread_stack_free_rcu (kernel/fork.c:867) [ 6.962955][ T22] ? handle_exception (arch/x86/entry/entry_32.S:1047) [ 6.963399][ T22] ? thread_stack_free_rcu (kernel/fork.c:867) [ 6.963801][ T22] ? exc_overflow (arch/x86/kernel/traps.c:301) [ 6.964203][ T22] ? hazptr_scan (kernel/hazptr.c:28) [ 6.964544][ T22] ? exc_overflow (arch/x86/kernel/traps.c:301) [ 6.964895][ T22] ? hazptr_scan (kernel/hazptr.c:28) [ 6.965279][ T22] __mmdrop (kernel/fork.c:895 (discriminator 3)) [ 6.965599][ T22] collect_mm_slot (mm/khugepaged.c:1455) [ 6.965952][ T22] khugepaged_scan_mm_slot+0x210/0x60c [ 6.966493][ T22] ? khugepaged (mm/khugepaged.c:2511 mm/khugepaged.c:2571) [ 6.966865][ T22] khugepaged (mm/khugepaged.c:2515 mm/khugepaged.c:2571) [ 6.967239][ T22] ? _raw_spin_unlock_irqrestore (arch/x86/include/asm/irqflags.h:42 arch/x86/include/asm/irqflags.h:97 arch/x86/include/asm/irqflags.h:155 include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) [ 6.967684][ T22] ? __kthread_parkme (arch/x86/include/asm/bitops.h:206 arch/x86/include/asm/bitops.h:238 include/asm-generic/bitops/instrumented-non-atomic.h:142 kernel/kthread.c:280) [ 6.968102][ T22] kthread (kernel/kthread.c:389) [ 6.968400][ T22] ? khugepaged_scan_mm_slot+0x60c/0x60c [ 6.968896][ T22] ? kthread_park (kernel/kthread.c:342) [ 6.969286][ T22] ret_from_fork (arch/x86/kernel/process.c:153) [ 6.969628][ T22] ? kthread_park (kernel/kthread.c:342) [ 6.969961][ T22] ret_from_fork_asm (arch/x86/entry/entry_32.S:737) [ 6.970383][ T22] entry_INT80_32 (arch/x86/entry/entry_32.S:944) [ 6.970758][ T22] irq event stamp: 4719 [ 6.971117][ T22] hardirqs last enabled at (4729): __up_console_sem (arch/x86/include/asm/irqflags.h:42 (discriminator 1) arch/x86/include/asm/irqflags.h:97 (discriminator 1) arch/x86/include/asm/irqflags.h:155 (discriminator 1) kernel/printk/printk.c:344 (discriminator 1)) [ 6.971790][ T22] hardirqs last disabled at (4736): __up_console_sem (kernel/printk/printk.c:342 (discriminator 1)) [ 6.972475][ T22] softirqs last enabled at (4708): handle_softirqs (kernel/softirq.c:401 kernel/softirq.c:582) [ 6.973162][ T22] softirqs last disabled at (4695): __do_softirq (kernel/softirq.c:589) [ 6.973771][ T22] ---[ end trace 0000000000000000 ]--- The kernel config and materials to reproduce are available at: https://download.01.org/0day-ci/archive/20241014/202410141617.612a0f5b-lkp@xxxxxxxxx -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki