net: Fix percpu counters deadlock

When we converted the protocol atomic counters such as the orphan
count and the total socket count deadlocks were introduced due to
the mismatch in BH status of the spots that used the percpu counter
operations.

Based on the diagnosis and patch by Peter Zijlstra, this patch
fixes these issues by disabling BH where we may be in process
context.

Reported-by: Jeff Kirsher <[email protected]>
Tested-by: Ingo Molnar <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
This commit is contained in:
Herbert Xu 2008-12-29 23:04:08 -08:00 • committed by David S. Miller
commit eb4dea5853
6 changed files with 21 additions and 8 deletions

View file

@ -23,6 +23,7 @@
* 2 of the License, or (at your option) any later version.
*/
#include <linux/bottom_half.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/types.h>
@ -1830,7 +1831,9 @@ static int tcp_v6_init_sock(struct sock *sk)
sk->sk_sndbuf = sysctl_tcp_wmem[1];
sk->sk_rcvbuf = sysctl_tcp_rmem[1];
local_bh_disable();
percpu_counter_inc(&tcp_sockets_allocated);
local_bh_enable();
return 0;
}