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| author | Jarek Poplawski <jarkao2@gmail.com> | 2008-02-11 21:24:56 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2008-02-12 17:53:31 -0800 |
| commit | 1105b5d1d44e6f00e31422dfcb0139bc8ae966a9 (patch) | |
| tree | 14cf0671196b0dbe3de6c51fede38b6d70164850 /net/ax25 | |
| parent | 8315f5d80a90247bf92232f92ca49933ac49327b (diff) | |
| download | linux-1105b5d1d44e6f00e31422dfcb0139bc8ae966a9.tar.gz linux-1105b5d1d44e6f00e31422dfcb0139bc8ae966a9.tar.bz2 linux-1105b5d1d44e6f00e31422dfcb0139bc8ae966a9.zip | |
[AX25] af_ax25: remove sock lock in ax25_info_show()
This lockdep warning:
> =======================================================
> [ INFO: possible circular locking dependency detected ]
> 2.6.24 #3
> -------------------------------------------------------
> swapper/0 is trying to acquire lock:
> (ax25_list_lock){-+..}, at: [<f91dd3b1>] ax25_destroy_socket+0x171/0x1f0 [ax25]
>
> but task is already holding lock:
> (slock-AF_AX25){-+..}, at: [<f91dbabc>] ax25_std_heartbeat_expiry+0x1c/0xe0 [ax25]
>
> which lock already depends on the new lock.
...
shows that ax25_list_lock and slock-AF_AX25 are taken in different
order: ax25_info_show() takes slock (bh_lock_sock(ax25->sk)) while
ax25_list_lock is held, so reversely to other functions. To fix this
the sock lock should be moved to ax25_info_start(), and there would
be still problem with breaking ax25_list_lock (it seems this "proper"
order isn't optimal yet). But, since it's only for reading proc info
it seems this is not necessary (e.g. ax25_send_to_raw() does similar
reading without this lock too).
So, this patch removes sock lock to avoid deadlock possibility; there
is also used sock_i_ino() function, which reads sk_socket under proper
read lock. Additionally printf format of this i_ino is changed to %lu.
Reported-by: Bernard Pidoux F6BVP <f6bvp@free.fr>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ax25')
| -rw-r--r-- | net/ax25/af_ax25.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c index 8fc64e3150a2..5a4337a29094 100644 --- a/net/ax25/af_ax25.c +++ b/net/ax25/af_ax25.c @@ -1928,12 +1928,10 @@ static int ax25_info_show(struct seq_file *seq, void *v) ax25->paclen); if (ax25->sk != NULL) { - bh_lock_sock(ax25->sk); - seq_printf(seq," %d %d %ld\n", + seq_printf(seq, " %d %d %lu\n", atomic_read(&ax25->sk->sk_wmem_alloc), atomic_read(&ax25->sk->sk_rmem_alloc), - ax25->sk->sk_socket != NULL ? SOCK_INODE(ax25->sk->sk_socket)->i_ino : 0L); - bh_unlock_sock(ax25->sk); + sock_i_ino(ax25->sk)); } else { seq_puts(seq, " * * *\n"); } |