Re: [RFC PATCH v2 4/4] sched+mm: Use hazard pointers to track lazy active mm existence

[Mathieu Desnoyers]

On 2024-10-07 16:50, kernel test robot wrote:
> Hello,
>
> kernel test robot noticed "BUG:using_smp_processor_id()in_preemptible" on:
>
> commit: efef4da3b19cadf4beb45079a05643a77821de79 ("[RFC PATCH v2 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/20241005-023027
> base: https://git.kernel.org/cgit/linux/kernel/git/powerpc/linux.git next
> patch link: https://lore.kernel.org/all/20241004182734.1761555-5-mathieu.desnoyers@xxxxxxxxxxxx/
> patch subject: [RFC PATCH v2 4/4] sched+mm: Use hazard pointers to track lazy active mm existence

This should do the trick:

-       WRITE_ONCE(this_cpu_ptr(hp_domain_sched_lazy_mm.percpu_slots)->addr, NULL);
+       this_cpu_write(hp_domain_sched_lazy_mm.percpu_slots->addr, NULL);

I'll update the patch for the next round.

Thanks,

Mathieu


> in testcase: boot
>
> compiler: gcc-12
> test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 4G
>
> (please refer to attached dmesg/kmsg for entire log/backtrace)
>
>
> +--------------------------------------------+------------+------------+
> |                                            | 75b478bf10 | efef4da3b1 |
> +--------------------------------------------+------------+------------+
> | BUG:using_smp_processor_id()in_preemptible | 0          | 12         |
> +--------------------------------------------+------------+------------+
>
>
> 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/202410072229.18756716-oliver.sang@xxxxxxxxx
>
>
> [    6.336856][   T48] BUG: using smp_processor_id() in preemptible [00000000] code: kworker/u10:1/48
> [ 6.338102][ T48] caller is debug_smp_processor_id (lib/smp_processor_id.c:61)
> [    6.338809][   T48] CPU: 0 UID: 0 PID: 48 Comm: kworker/u10:1 Not tainted 6.12.0-rc1-00004-gefef4da3b19c #5
> [    6.339929][   T48] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
> [    6.341119][   T48] Call Trace:
> [ 6.341504][ T48] dump_stack_lvl (lib/dump_stack.c:123)
> [ 6.342057][ T48] dump_stack (lib/dump_stack.c:130)
> [ 6.342065][ T48] check_preemption_disabled (arch/x86/include/asm/preempt.h:84 lib/smp_processor_id.c:53)
> [ 6.342065][ T48] debug_smp_processor_id (lib/smp_processor_id.c:61)
> [ 6.342065][ T48] exec_mmap (include/linux/sched/mm.h:91 fs/exec.c:1017)
> [ 6.342065][ T48] ? would_dump (fs/exec.c:1409)
> [ 6.342065][ T48] begin_new_exec (fs/exec.c:1280)
> [ 6.342065][ T48] ? load_elf_phdrs (fs/binfmt_elf.c:534)
> [ 6.342065][ T48] load_elf_binary (fs/binfmt_elf.c:996)
> [ 6.342065][ T48] ? get_lock_stats (kernel/locking/lockdep.c:339)
> [ 6.342065][ T48] ? search_binary_handler (fs/exec.c:1752)
> [ 6.342065][ T48] search_binary_handler (fs/exec.c:1752)
> [ 6.342065][ T48] exec_binprm (fs/exec.c:1795)
> [ 6.342065][ T48] bprm_execve (fs/exec.c:1846 fs/exec.c:1821)
> [ 6.342065][ T48] kernel_execve (fs/exec.c:2012)
> [ 6.342065][ T48] call_usermodehelper_exec_async (kernel/umh.c:110)
> [ 6.342065][ T48] ? umh_complete (kernel/umh.c:65)
> [ 6.342065][ T48] ret_from_fork (arch/x86/kernel/process.c:153)
> [ 6.342065][ T48] ? umh_complete (kernel/umh.c:65)
> [ 6.342065][ T48] ret_from_fork_asm (arch/x86/entry/entry_32.S:737)
> [ 6.342065][ T48] entry_INT80_32 (arch/x86/entry/entry_32.S:944)
> [    6.352140][    T1] ppdev: user-space parallel port driver
> [    6.353841][    T1] HSI/SSI char device loaded
> [    6.354238][    T1] e1000: Intel(R) PRO/1000 Network Driver
> [    6.354673][    T1] e1000: Copyright (c) 1999-2006 Intel Corporation.
> [    6.650009][    T1] ACPI: _SB_.LNKC: Enabled at IRQ 11
> [    6.968868][    T1] e1000 0000:00:03.0 eth0: (PCI:33MHz:32-bit) 52:54:00:12:34:56
> [    6.969500][    T1] e1000 0000:00:03.0 eth0: Intel(R) PRO/1000 Network Connection
> [    6.970506][   T49] BUG: using smp_processor_id() in preemptible [00000000] code: kworker/u10:1/49
> [ 6.971191][ T49] caller is debug_smp_processor_id (lib/smp_processor_id.c:61)
> [    6.971650][   T49] CPU: 0 UID: 0 PID: 49 Comm: kworker/u10:1 Not tainted 6.12.0-rc1-00004-gefef4da3b19c #5
> [    6.972365][   T49] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
> [    6.973115][   T49] Call Trace:
> [ 6.973356][ T49] dump_stack_lvl (lib/dump_stack.c:123)
> [ 6.973686][ T49] dump_stack (lib/dump_stack.c:130)
> [ 6.973983][ T49] check_preemption_disabled (arch/x86/include/asm/preempt.h:84 lib/smp_processor_id.c:53)
> [ 6.974328][ T49] debug_smp_processor_id (lib/smp_processor_id.c:61)
> [ 6.974328][ T49] exec_mmap (include/linux/sched/mm.h:91 fs/exec.c:1017)
> [ 6.974328][ T49] ? would_dump (fs/exec.c:1409)
> [ 6.974328][ T49] begin_new_exec (fs/exec.c:1280)
> [ 6.974328][ T49] ? load_elf_phdrs (fs/binfmt_elf.c:534)
> [ 6.974328][ T49] load_elf_binary (fs/binfmt_elf.c:996)
> [ 6.974328][ T49] ? get_lock_stats (kernel/locking/lockdep.c:339)
> [ 6.974328][ T49] ? search_binary_handler (fs/exec.c:1752)
> [ 6.974328][ T49] search_binary_handler (fs/exec.c:1752)
> [ 6.974328][ T49] exec_binprm (fs/exec.c:1795)
> [ 6.974328][ T49] bprm_execve (fs/exec.c:1846 fs/exec.c:1821)
> [ 6.974328][ T49] kernel_execve (fs/exec.c:2012)
> [ 6.974328][ T49] call_usermodehelper_exec_async (kernel/umh.c:110)
> [ 6.974328][ T49] ? umh_complete (kernel/umh.c:65)
> [ 6.974328][ T49] ret_from_fork (arch/x86/kernel/process.c:153)
> [ 6.974328][ T49] ? umh_complete (kernel/umh.c:65)
> [ 6.974328][ T49] ret_from_fork_asm (arch/x86/entry/entry_32.S:737)
> [ 6.974328][ T49] entry_INT80_32 (arch/x86/entry/entry_32.S:944)
>
>
>
> The kernel config and materials to reproduce are available at:
> https://download.01.org/0day-ci/archive/20241007/202410072229.18756716-oliver.sang@xxxxxxxxx

--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com