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authorHerbert Xu <herbert@gondor.apana.org.au>2008-12-30 10:04:08 +0300
committerDavid S. Miller <davem@davemloft.net>2008-12-30 10:04:08 +0300
commiteb4dea5853046727bfbb579f0c9a8cae7369f7c6 (patch)
tree79e18d6284494ab63a890885b0eecce9431a9597 /net/ipv4/proc.c
parent0f23174aa8c1aa7a2a6050a72a60d290ef9ee578 (diff)
downloadlinux-eb4dea5853046727bfbb579f0c9a8cae7369f7c6.tar.xz
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 <jeffrey.t.kirsher@intel.com> Tested-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/proc.c')
-rw-r--r--net/ipv4/proc.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index 614958b7c276..eb62e58bff79 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -38,6 +38,7 @@
#include <net/tcp.h>
#include <net/udp.h>
#include <net/udplite.h>
+#include <linux/bottom_half.h>
#include <linux/inetdevice.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
@@ -50,13 +51,17 @@
static int sockstat_seq_show(struct seq_file *seq, void *v)
{
struct net *net = seq->private;
+ int orphans, sockets;
+
+ local_bh_disable();
+ orphans = percpu_counter_sum_positive(&tcp_orphan_count),
+ sockets = percpu_counter_sum_positive(&tcp_sockets_allocated),
+ local_bh_enable();
socket_seq_show(seq);
seq_printf(seq, "TCP: inuse %d orphan %d tw %d alloc %d mem %d\n",
- sock_prot_inuse_get(net, &tcp_prot),
- (int)percpu_counter_sum_positive(&tcp_orphan_count),
- tcp_death_row.tw_count,
- (int)percpu_counter_sum_positive(&tcp_sockets_allocated),
+ sock_prot_inuse_get(net, &tcp_prot), orphans,
+ tcp_death_row.tw_count, sockets,
atomic_read(&tcp_memory_allocated));
seq_printf(seq, "UDP: inuse %d mem %d\n",
sock_prot_inuse_get(net, &udp_prot),