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  1. 15 Aug, 2012 3 commits
    • Ben Hutchings's avatar
      ipv6: addrconf: Avoid calling netdevice notifiers with RCU read-side lock · 4acd4945
      Ben Hutchings authored 
      Cong Wang reports that lockdep detected suspicious RCU usage while
enabling IPV6 forwarding:

 [ 1123.310275] ===============================
 [ 1123.442202] [ INFO: suspicious RCU usage. ]
 [ 1123.558207] 3.6.0-rc1+ #109 Not tainted
 [ 1123.665204] -------------------------------
 [ 1123.768254] include/linux/rcupdate.h:430 Illegal context switch in RCU read-side critical section!
 [ 1123.992320]
 [ 1123.992320] other info that might help us debug this:
 [ 1123.992320]
 [ 1124.307382]
 [ 1124.307382] rcu_scheduler_active = 1, debug_locks = 0
 [ 1124.522220] 2 locks held by sysctl/5710:
 [ 1124.648364]  #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff81768498>] rtnl_trylock+0x15/0x17
 [ 1124.882211]  #1:  (rcu_read_lock){.+.+.+}, at: [<ffffffff81871df8>] rcu_lock_acquire+0x0/0x29
 [ 1125.085209]
 [ 1125.085209] stack backtrace:
 [ 1125.332213] Pid: 5710, comm: sysctl Not tainted 3.6.0-rc1+ #109
 [ 1125.441291] Call Trace:
 [ 1125.545281]  [<ffffffff8109d915>] lockdep_rcu_suspicious+0x109/0x112
 [ 1125.667212]  [<ffffffff8107c240>] rcu_preempt_sleep_check+0x45/0x47
 [ 1125.781838]  [<ffffffff8107c260>] __might_sleep+0x1e/0x19b
[...]
 [ 1127.445223]  [<ffffffff81757ac5>] call_netdevice_notifiers+0x4a/0x4f
[...]
 [ 1127.772188]  [<ffffffff8175e125>] dev_disable_lro+0x32/0x6b
 [ 1127.885174]  [<ffffffff81872d26>] dev_forward_change+0x30/0xcb
 [ 1128.013214]  [<ffffffff818738c4>] addrconf_forward_change+0x85/0xc5
[...]

addrconf_forward_change() uses RCU iteration over the netdev list,
which is unnecessary since it already holds the RTNL lock.  We also
cannot reasonably require netdevice notifier functions not to sleep.
Reported-by: default avatarCong Wang <amwang@redhat.com>
Signed-off-by: default avatarBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      4acd4945
    • Julia Lawall's avatar
      drivers/net/ethernet/mellanox/mlx4/mcg.c: fix error return code · 499b95f6
      Julia Lawall authored 
      Convert a 0 error return code to a negative one, as returned elsewhere in the
function.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier ret;
expression e,e1,e2,e3,e4,x;
@@

(
if (\(ret != 0\|ret < 0\) || ...) { ... return ...; }
|
ret = 0
)
... when != ret = e1
*x = \(kmalloc\|kzalloc\|kcalloc\|devm_kzalloc\|ioremap\|ioremap_nocache\|devm_ioremap\|devm_ioremap_nocache\)(...);
... when != x = e2
    when != ret = e3
*if (x == NULL || ...)
{
  ... when != ret = e4
*  return ret;
}
// </smpl>
Signed-off-by: default avatarJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      499b95f6
    • Julia Lawall's avatar
      drivers/net/ethernet/freescale/fs_enet: fix error return code · 137bc99f
      Julia Lawall authored 
      Convert a 0 error return code to a negative one, as returned elsewhere in the
function.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier ret;
expression e,e1,e2,e3,e4,x;
@@

(
if (\(ret != 0\|ret < 0\) || ...) { ... return ...; }
|
ret = 0
)
... when != ret = e1
*x = \(kmalloc\|kzalloc\|kcalloc\|devm_kzalloc\|ioremap\|ioremap_nocache\|devm_ioremap\|devm_ioremap_nocache\)(...);
... when != x = e2
    when != ret = e3
*if (x == NULL || ...)
{
  ... when != ret = e4
*  return ret;
}
// </smpl>
Signed-off-by: default avatarJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      137bc99f
  3. 14 Aug, 2012 28 commits
  5. 13 Aug, 2012 9 commits
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