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    IB/ucma: Fix lockdep warning in ucma_lock_files · 31b57b87
    Haggai Eran 提交于
    The ucma_lock_files() locks the mut mutex on two files, e.g. for migrating
    an ID. Use mutex_lock_nested() to prevent the warning below.
    
     =============================================
     [ INFO: possible recursive locking detected ]
     4.1.0-rc6-hmm+ #40 Tainted: G           O
     ---------------------------------------------
     pingpong_rpc_se/10260 is trying to acquire lock:
      (&file->mut){+.+.+.}, at: [<ffffffffa047ac55>] ucma_migrate_id+0xc5/0x248 [rdma_ucm]
    
     but task is already holding lock:
      (&file->mut){+.+.+.}, at: [<ffffffffa047ac4b>] ucma_migrate_id+0xbb/0x248 [rdma_ucm]
    
     other info that might help us debug this:
      Possible unsafe locking scenario:
    
            CPU0
            ----
       lock(&file->mut);
       lock(&file->mut);
    
      *** DEADLOCK ***
    
      May be due to missing lock nesting notation
    
     1 lock held by pingpong_rpc_se/10260:
      #0:  (&file->mut){+.+.+.}, at: [<ffffffffa047ac4b>] ucma_migrate_id+0xbb/0x248 [rdma_ucm]
    
     stack backtrace:
     CPU: 0 PID: 10260 Comm: pingpong_rpc_se Tainted: G           O    4.1.0-rc6-hmm+ #40
     Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2007
      ffff8801f85b63d0 ffff880195677b58 ffffffff81668f49 0000000000000001
      ffffffff825cbbe0 ffff880195677c38 ffffffff810bb991 ffff880100000000
      ffff880100000000 ffff880100000001 ffff8801f85b7010 ffffffff8121bee9
     Call Trace:
      [<ffffffff81668f49>] dump_stack+0x4f/0x6e
      [<ffffffff810bb991>] __lock_acquire+0x741/0x1820
      [<ffffffff8121bee9>] ? dput+0x29/0x320
      [<ffffffff810bcb38>] lock_acquire+0xc8/0x240
      [<ffffffffa047ac55>] ? ucma_migrate_id+0xc5/0x248 [rdma_ucm]
      [<ffffffff8166b901>] ? mutex_lock_nested+0x291/0x3e0
      [<ffffffff8166b6d5>] mutex_lock_nested+0x65/0x3e0
      [<ffffffffa047ac55>] ? ucma_migrate_id+0xc5/0x248 [rdma_ucm]
      [<ffffffff810baeed>] ? trace_hardirqs_on+0xd/0x10
      [<ffffffff8166b66e>] ? mutex_unlock+0xe/0x10
      [<ffffffffa047ac55>] ucma_migrate_id+0xc5/0x248 [rdma_ucm]
      [<ffffffffa0478474>] ucma_write+0xa4/0xb0 [rdma_ucm]
      [<ffffffff81200674>] __vfs_write+0x34/0x100
      [<ffffffff8112427c>] ? __audit_syscall_entry+0xac/0x110
      [<ffffffff810ec055>] ? current_kernel_time+0xc5/0xe0
      [<ffffffff812aa4d3>] ? security_file_permission+0x23/0x90
      [<ffffffff8120088d>] ? rw_verify_area+0x5d/0xe0
      [<ffffffff812009bb>] vfs_write+0xab/0x120
      [<ffffffff81201519>] SyS_write+0x59/0xd0
      [<ffffffff8112427c>] ? __audit_syscall_entry+0xac/0x110
      [<ffffffff8166ffee>] system_call_fastpath+0x12/0x76
    Signed-off-by: NHaggai Eran <haggaie@mellanox.com>
    Signed-off-by: NDoug Ledford <dledford@redhat.com>
    31b57b87
ucma.c 38.3 KB