net: fib: fix incorrect call_rcu_bh()

After IP route cache removal, I believe rcu_bh() has very little use and
we should remove this RCU variant, since it adds some cycles in fast
path.
Anyway, the call_rcu_bh() use in fib_true is obviously wrong, since
some users only assert rcu_read_lock().

4619.617291:   <0> Internal error: Oops: 5 [#1] PREEMPT SMP ARM
114619.622541:   <4> Modules linked in: wlan(O) adsprpc [last unloaded: wlan]
114619.628980:   <4> CPU: 1    Tainted: G        W  O  (3.4.0-g366f2d7-00028-gde45140 #1)
114619.636427:   <4> PC is at leaf_walk_rcu+0x50/0x9c
114619.640761:   <4> LR is at fib_route_seq_next+0x58/0x7c
...[ Dmesg snip snip ]...
14620.187747:   <0> 5fe0: 405a3cd4 405a3ca0 007207ac 0071c098 80000010 00000012 00000000 00000000
114620.196018:   <4> [<c0720ec4>] (leaf_walk_rcu+0x50/0x9c) from [<c07210b0>] (fib_route_seq_next+0x58/0x7c)
114620.205114:   <4> [<c07210b0>] (fib_route_seq_next+0x58/0x7c) from [<c01642d8>] (seq_read+0x304/0x498)
114620.213964:   <4> [<c01642d8>] (seq_read+0x304/0x498) from [<c018daf8>] (proc_reg_read+0x80/0x98)
114620.222388:   <4> [<c018daf8>] (proc_reg_read+0x80/0x98) from [<c0147e90>] (vfs_read+0xa4/0x12c)
114620.230720:   <4> [<c0147e90>] (vfs_read+0xa4/0x12c) from [<c0147f4c>] (sys_read+0x34/0x68)
114620.238625:   <4> [<c0147f4c>] (sys_read+0x34/0x68) from [<c000e2e0>] (ret_fast_syscall+0x0/0x30)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Git-commit: 0c03eca3d995e73d691edea8c787e25929ec156d
Git-repo: https://www.codeaurora.org/cgit/quic/la/kernel/msm-3.10
Signed-off-by: Vijaya Kumar T M <vtmuni@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Bluetooth: Prevent Bluetooth L2CAP Remote Heap Memory Corruption

A remote user can provide a small value for the command size field in
the command header of an l2cap configuration request, resulting in an
integer underflow when subtracting the size of the configuration request
header.  This results in copying a very large amount of data via
memcpy() and destroying the kernel heap.  Check for underflow.

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>