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authorEric Dumazet <edumazet@google.com>2019-11-08 03:27:21 +0300
committerDavid S. Miller <davem@davemloft.net>2019-11-08 07:03:08 +0300
commit5260dd3ed1ff7eba39251b28977e4d8950e2f099 (patch)
treea0719e0e55fa98b274b2bcc7ff048798df441e00 /drivers/net/tun.c
parent316580b69d0a7aeeee5063af47438b626bc47cbd (diff)
downloadlinux-5260dd3ed1ff7eba39251b28977e4d8950e2f099.tar.xz
tun: switch to u64_stats_t
In order to fix this data-race found by KCSAN [1], switch to u64_stats_t helpers. They provide all the needed annotations, without adding extra cost. [1] BUG: KCSAN: data-race in tun_get_user / tun_net_get_stats64 read to 0xffffe8ffffd8aca8 of 8 bytes by task 4882 on cpu 0: tun_net_get_stats64+0x9b/0x230 drivers/net/tun.c:1171 dev_get_stats+0x89/0x1e0 net/core/dev.c:9103 rtnl_fill_stats+0x56/0x370 net/core/rtnetlink.c:1177 rtnl_fill_ifinfo+0xd3b/0x2100 net/core/rtnetlink.c:1667 rtmsg_ifinfo_build_skb+0xb0/0x150 net/core/rtnetlink.c:3472 rtmsg_ifinfo_event.part.0+0x4e/0xb0 net/core/rtnetlink.c:3504 rtmsg_ifinfo_event net/core/rtnetlink.c:3515 [inline] rtmsg_ifinfo+0x85/0x90 net/core/rtnetlink.c:3513 __dev_notify_flags+0x18b/0x200 net/core/dev.c:7649 dev_change_flags+0xb8/0xe0 net/core/dev.c:7691 dev_ifsioc+0x201/0x6a0 net/core/dev_ioctl.c:237 dev_ioctl+0x149/0x660 net/core/dev_ioctl.c:489 sock_do_ioctl+0xdb/0x230 net/socket.c:1061 sock_ioctl+0x3a3/0x5e0 net/socket.c:1189 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x991/0xc60 fs/ioctl.c:696 write to 0xffffe8ffffd8aca8 of 8 bytes by task 4883 on cpu 1: tun_get_user+0x1d94/0x2ba0 drivers/net/tun.c:2002 tun_chr_write_iter+0x79/0xd0 drivers/net/tun.c:2022 call_write_iter include/linux/fs.h:1895 [inline] new_sync_write+0x388/0x4a0 fs/read_write.c:483 __vfs_write+0xb1/0xc0 fs/read_write.c:496 __kernel_write+0xb8/0x240 fs/read_write.c:515 write_pipe_buf+0xb6/0xf0 fs/splice.c:794 splice_from_pipe_feed fs/splice.c:500 [inline] __splice_from_pipe+0x248/0x480 fs/splice.c:624 splice_from_pipe+0xbb/0x100 fs/splice.c:659 default_file_splice_write+0x45/0x90 fs/splice.c:806 do_splice_from fs/splice.c:848 [inline] direct_splice_actor+0xa0/0xc0 fs/splice.c:1020 splice_direct_to_actor+0x215/0x510 fs/splice.c:975 do_splice_direct+0x161/0x1e0 fs/splice.c:1063 do_sendfile+0x384/0x7f0 fs/read_write.c:1464 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 4883 Comm: syz-executor.1 Not tainted 5.4.0-rc3+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/tun.c')
-rw-r--r--drivers/net/tun.c32
1 files changed, 16 insertions, 16 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index dab6cccfeb52..dcb63f1f9110 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -136,10 +136,10 @@ struct tap_filter {
#define TUN_FLOW_EXPIRE (3 * HZ)
struct tun_pcpu_stats {
- u64 rx_packets;
- u64 rx_bytes;
- u64 tx_packets;
- u64 tx_bytes;
+ u64_stats_t rx_packets;
+ u64_stats_t rx_bytes;
+ u64_stats_t tx_packets;
+ u64_stats_t tx_bytes;
struct u64_stats_sync syncp;
u32 rx_dropped;
u32 tx_dropped;
@@ -1167,10 +1167,10 @@ tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
p = per_cpu_ptr(tun->pcpu_stats, i);
do {
start = u64_stats_fetch_begin(&p->syncp);
- rxpackets = p->rx_packets;
- rxbytes = p->rx_bytes;
- txpackets = p->tx_packets;
- txbytes = p->tx_bytes;
+ rxpackets = u64_stats_read(&p->rx_packets);
+ rxbytes = u64_stats_read(&p->rx_bytes);
+ txpackets = u64_stats_read(&p->tx_packets);
+ txbytes = u64_stats_read(&p->tx_bytes);
} while (u64_stats_fetch_retry(&p->syncp, start));
stats->rx_packets += rxpackets;
@@ -1998,8 +1998,8 @@ drop:
stats = get_cpu_ptr(tun->pcpu_stats);
u64_stats_update_begin(&stats->syncp);
- stats->rx_packets++;
- stats->rx_bytes += len;
+ u64_stats_inc(&stats->rx_packets);
+ u64_stats_add(&stats->rx_bytes, len);
u64_stats_update_end(&stats->syncp);
put_cpu_ptr(stats);
@@ -2052,8 +2052,8 @@ static ssize_t tun_put_user_xdp(struct tun_struct *tun,
stats = get_cpu_ptr(tun->pcpu_stats);
u64_stats_update_begin(&stats->syncp);
- stats->tx_packets++;
- stats->tx_bytes += ret;
+ u64_stats_inc(&stats->tx_packets);
+ u64_stats_add(&stats->tx_bytes, ret);
u64_stats_update_end(&stats->syncp);
put_cpu_ptr(tun->pcpu_stats);
@@ -2147,8 +2147,8 @@ done:
/* caller is in process context, */
stats = get_cpu_ptr(tun->pcpu_stats);
u64_stats_update_begin(&stats->syncp);
- stats->tx_packets++;
- stats->tx_bytes += skb->len + vlan_hlen;
+ u64_stats_inc(&stats->tx_packets);
+ u64_stats_add(&stats->tx_bytes, skb->len + vlan_hlen);
u64_stats_update_end(&stats->syncp);
put_cpu_ptr(tun->pcpu_stats);
@@ -2511,8 +2511,8 @@ build:
*/
stats = this_cpu_ptr(tun->pcpu_stats);
u64_stats_update_begin(&stats->syncp);
- stats->rx_packets++;
- stats->rx_bytes += datasize;
+ u64_stats_inc(&stats->rx_packets);
+ u64_stats_add(&stats->rx_bytes, datasize);
u64_stats_update_end(&stats->syncp);
if (rxhash)