1. 23 Sep, 2020 1 commit
  2. 22 Sep, 2020 1 commit
  3. 21 Sep, 2020 2 commits
    • Ulf Hansson's avatar
      cpuidle: psci: Fix suspicious RCU usage · 36050d89
      Ulf Hansson authored
      The commit eb1f0023 ("lockdep,trace: Expose tracepoints"), started to
      expose us for tracepoints. This lead to the following RCU splat on an ARM64
      Qcom board.
      
      [    5.529634] WARNING: suspicious RCU usage
      [    5.537307] sdhci-pltfm: SDHCI platform and OF driver helper
      [    5.541092] 5.9.0-rc3 #86 Not tainted
      [    5.541098] -----------------------------
      [    5.541105] ../include/trace/events/lock.h:37 suspicious rcu_dereference_check() usage!
      [    5.541110]
      [    5.541110] other info that might help us debug this:
      [    5.541110]
      [    5.541116]
      [    5.541116] rcu_scheduler_active = 2, debug_locks = 1
      [    5.541122] RCU used illegally from extended quiescent state!
      [    5.541129] no locks held by swapper/0/0.
      [    5.541134]
      [    5.541134] stack backtrace:
      [    5.541143] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.9.0-rc3 #86
      [    5.541149] Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT)
      [    5.541157] Call trace:
      [    5.568185] sdhci_msm 7864900.sdhci: Got CD GPIO
      [    5.574186]  dump_backtrace+0x0/0x1c8
      [    5.574206]  show_stack+0x14/0x20
      [    5.574229]  dump_stack+0xe8/0x154
      [    5.574250]  lockdep_rcu_suspicious+0xd4/0xf8
      [    5.574269]  lock_acquire+0x3f0/0x460
      [    5.574292]  _raw_spin_lock_irqsave+0x80/0xb0
      [    5.574314]  __pm_runtime_suspend+0x4c/0x188
      [    5.574341]  psci_enter_domain_idle_state+0x40/0xa0
      [    5.574362]  cpuidle_enter_state+0xc0/0x610
      [    5.646487]  cpuidle_enter+0x38/0x50
      [    5.650651]  call_cpuidle+0x18/0x40
      [    5.654467]  do_idle+0x228/0x278
      [    5.657678]  cpu_startup_entry+0x24/0x70
      [    5.661153]  rest_init+0x1a4/0x278
      [    5.665061]  arch_call_rest_init+0xc/0x14
      [    5.668272]  start_kernel+0x508/0x540
      
      Following the path in pm_runtime_put_sync_suspend() from
      psci_enter_domain_idle_state(), it seems like we end up using the RCU.
      Therefore, let's simply silence the splat by informing the RCU about it
      with RCU_NONIDLE.
      
      Note that, this is a temporary solution. Instead we should strive to avoid
      using RCU_NONIDLE (and similar), but rather push rcu_idle_enter|exit()
      further down, closer to the arch specific code. However, as the CPU PM
      notifiers are also using the RCU, additional rework is needed.
      Reported-by: default avatarNaresh Kamboju <naresh.kamboju@linaro.org>
      Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
      Acked-by: default avatarPaul E. McKenney <paulmck@kernel.org>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      36050d89
    • Borislav Petkov's avatar
      rcu/tree: Export rcu_idle_{enter,exit} to modules · 3ad1c8ef
      Borislav Petkov authored
      Fix this link error:
      
        ERROR: modpost: "rcu_idle_enter" [drivers/acpi/processor.ko] undefined!
        ERROR: modpost: "rcu_idle_exit" [drivers/acpi/processor.ko] undefined!
      
      when CONFIG_ACPI_PROCESSOR is built as module. PeterZ says that in light
      of ARM needing those soon too, they should simply be exported.
      
      Fixes: 1fecfdbb ("ACPI: processor: Take over RCU-idle for C3-BM idle")
      Reported-by: default avatarSven Joachim <svenjoac@gmx.de>
      Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarPaul E. McKenney <paulmckrcu@kernel.org>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      3ad1c8ef
  4. 20 Sep, 2020 20 commits
  5. 19 Sep, 2020 16 commits