1. 22 Aug, 2019 1 commit
    • Stephen Boyd's avatar
      random: Support freezable kthreads in add_hwgenerator_randomness() · ff296293
      Stephen Boyd authored
      The kthread calling this function is freezable after commit 03a3bb7a
      ("hwrng: core - Freeze khwrng thread during suspend") is applied.
      Unfortunately, this function uses wait_event_interruptible() but doesn't
      check for the kthread being woken up by the fake freezer signal. When a
      user suspends the system, this kthread will wake up and if it fails the
      entropy size check it will immediately go back to sleep and not go into
      the freezer. Eventually, suspend will fail because the task never froze
      and a warning message like this may appear:
      
       PM: suspend entry (deep)
       Filesystems sync: 0.000 seconds
       Freezing user space processes ... (elapsed 0.001 seconds) done.
       OOM killer disabled.
       Freezing remaining freezable tasks ...
       Freezing of tasks failed after 20.003 seconds (1 tasks refusing to freeze, wq_busy=0):
       hwrng           R  running task        0   289      2 0x00000020
       [<c08c64c4>] (__schedule) from [<c08c6a10>] (schedule+0x3c/0xc0)
       [<c08c6a10>] (schedule) from [<c05dbd8c>] (add_hwgenerator_randomness+0xb0/0x100)
       [<c05dbd8c>] (add_hwgenerator_randomness) from [<bf1803c8>] (hwrng_fillfn+0xc0/0x14c [rng_core])
       [<bf1803c8>] (hwrng_fillfn [rng_core]) from [<c015abec>] (kthread+0x134/0x148)
       [<c015abec>] (kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c)
      
      Check for a freezer signal here and skip adding any randomness if the
      task wakes up because it was frozen. This should make the kthread freeze
      properly and suspend work again.
      
      Fixes: 03a3bb7a ("hwrng: core - Freeze khwrng thread during suspend")
      Reported-by: default avatarKeerthy <j-keerthy@ti.com>
      Tested-by: default avatarKeerthy <j-keerthy@ti.com>
      Signed-off-by: default avatarStephen Boyd <swboyd@chromium.org>
      Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      ff296293
  2. 15 Aug, 2019 18 commits
  3. 09 Aug, 2019 21 commits