1. 25 Jul, 2018 2 commits
    • Peter Rosin's avatar
      i2c/mux, locking/core: Annotate the nested rt_mutex usage · 7b94ea50
      Peter Rosin authored
      If an i2c topology has instances of nested muxes, then a lockdep splat
      is produced when when i2c_parent_lock_bus() is called.  Here is an
      example:
      
        ============================================
        WARNING: possible recursive locking detected
        --------------------------------------------
        insmod/68159 is trying to acquire lock:
          (i2c_register_adapter#2){+.+.}, at: i2c_parent_lock_bus+0x32/0x50 [i2c_mux]
      
        but task is already holding lock:
          (i2c_register_adapter#2){+.+.}, at: i2c_parent_lock_bus+0x32/0x50 [i2c_mux]
      
        other info that might help us debug this:
          Possible unsafe locking scenario:
      
                CPU0
                ----
           lock(i2c_register_adapter#2);
           lock(i2c_register_adapter#2);
      
          *** DEADLOCK ***
      
          May be due to missing lock nesting notation
      
        1 lock held by insmod/68159:
          #0:  (i2c_register_adapter#2){+.+.}, at: i2c_parent_lock_bus+0x32/0x50 [i2c_mux]
      
        stack backtrace:
        CPU: 13 PID: 68159 Comm: insmod Tainted: G           O
        Call Trace:
          dump_stack+0x67/0x98
          __lock_acquire+0x162e/0x1780
          lock_acquire+0xba/0x200
          rt_mutex_lock+0x44/0x60
          i2c_parent_lock_bus+0x32/0x50 [i2c_mux]
          i2c_parent_lock_bus+0x3e/0x50 [i2c_mux]
          i2c_smbus_xfer+0xf0/0x700
          i2c_smbus_read_byte+0x42/0x70
          my2c_init+0xa2/0x1000 [my2c]
          do_one_initcall+0x51/0x192
          do_init_module+0x62/0x216
          load_module+0x20f9/0x2b50
          SYSC_init_module+0x19a/0x1c0
          SyS_init_module+0xe/0x10
          do_syscall_64+0x6c/0x1a0
          entry_SYSCALL_64_after_hwframe+0x42/0xb7
      Reported-by: default avatarJohn Sperbeck <jsperbeck@google.com>
      Tested-by: default avatarJohn Sperbeck <jsperbeck@google.com>
      Signed-off-by: default avatarPeter Rosin <peda@axentia.se>
      Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Cc: Davidlohr Bueso <dave@stgolabs.net>
      Cc: Deepa Dinamani <deepadinamani@google.com>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Chang <dpf@google.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Philippe Ombredanne <pombredanne@nexb.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: Wolfram Sang <wsa@the-dreams.de>
      Link: http://lkml.kernel.org/r/20180720083914.1950-3-peda@axentia.seSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      7b94ea50
    • Peter Rosin's avatar
      locking/rtmutex: Allow specifying a subclass for nested locking · 62cedf3e
      Peter Rosin authored
      Needed for annotating rt_mutex locks.
      Tested-by: default avatarJohn Sperbeck <jsperbeck@google.com>
      Signed-off-by: default avatarPeter Rosin <peda@axentia.se>
      Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Cc: Davidlohr Bueso <dave@stgolabs.net>
      Cc: Deepa Dinamani <deepadinamani@google.com>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Chang <dpf@google.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Philippe Ombredanne <pombredanne@nexb.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: Wolfram Sang <wsa@the-dreams.de>
      Link: http://lkml.kernel.org/r/20180720083914.1950-2-peda@axentia.seSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      62cedf3e
  2. 22 Jul, 2018 8 commits
  3. 21 Jul, 2018 12 commits
  4. 20 Jul, 2018 17 commits
  5. 19 Jul, 2018 1 commit