[-v3] Bluetooth: 6lowpan: use DEV_STAT_INC() to avoid races

Commit Message

Yunshui Jiang May 28, 2024, 2:26 a.m. UTC

syzbot/KCSAN reported that races happen when multiple cpus
updating dev->stats.tx_error concurrently.

Adopt SMP safe DEV_STATS_INC() to update dev->stats fields.

Signed-off-by: Yunshui Jiang <[e-mail]>
---
 net/bluetooth/6lowpan.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

Comments

[e-mail] May 28, 2024, 3:04 a.m. UTC | #1

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=856341

---Test result---

Test Summary:
CheckPatch                    PASS      0.46 seconds
GitLint                       PASS      0.19 seconds
SubjectPrefix                 PASS      0.06 seconds
BuildKernel                   PASS      29.45 seconds
CheckAllWarning               PASS      32.52 seconds
CheckSparse                   PASS      37.78 seconds
CheckSmatch                   FAIL      34.80 seconds
BuildKernel32                 PASS      28.65 seconds
TestRunnerSetup               PASS      521.62 seconds
TestRunner_l2cap-tester       PASS      18.17 seconds
TestRunner_iso-tester         PASS      32.60 seconds
TestRunner_bnep-tester        PASS      4.81 seconds
TestRunner_mgmt-tester        PASS      112.67 seconds
TestRunner_rfcomm-tester      PASS      7.35 seconds
TestRunner_sco-tester         PASS      14.94 seconds
TestRunner_ioctl-tester       PASS      7.78 seconds
TestRunner_mesh-tester        PASS      6.81 seconds
TestRunner_smp-tester         PASS      6.93 seconds
TestRunner_userchan-tester    PASS      4.99 seconds
IncrementalBuild              PASS      27.66 seconds

Details
##############################
Test: CheckSmatch - FAIL
Desc: Run smatch tool with source
Output:

Segmentation fault (core dumped)
make[4]: *** [scripts/Makefile.build:244: net/bluetooth/hci_core.o] Error 139
make[4]: *** Deleting file 'net/bluetooth/hci_core.o'
make[3]: *** [scripts/Makefile.build:485: net/bluetooth] Error 2
make[2]: *** [scripts/Makefile.build:485: net] Error 2
make[2]: *** Waiting for unfinished jobs....
Segmentation fault (core dumped)
make[4]: *** [scripts/Makefile.build:244: drivers/bluetooth/bcm203x.o] Error 139
make[4]: *** Deleting file 'drivers/bluetooth/bcm203x.o'
make[4]: *** Waiting for unfinished jobs....
make[3]: *** [scripts/Makefile.build:485: drivers/bluetooth] Error 2
make[2]: *** [scripts/Makefile.build:485: drivers] Error 2
make[1]: *** [/github/workspace/src/src/Makefile:1919: .] Error 2
make: *** [Makefile:240: __sub-make] Error 2


---
Regards,
Linux Bluetooth

Patch

diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index 50cfec8ccac4..8eb2cf58c00e 100644
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -295,8 +295,8 @@  static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
 			goto drop;
 		}
 
-		dev->stats.rx_bytes += skb->len;
-		dev->stats.rx_packets++;
+		DEV_STATS_ADD(dev, rx_bytes, skb->len);
+		DEV_STATS_INC(dev, rx_packets);
 
 		consume_skb(local_skb);
 		consume_skb(skb);
@@ -323,8 +323,8 @@  static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
 			goto drop;
 		}
 
-		dev->stats.rx_bytes += skb->len;
-		dev->stats.rx_packets++;
+		DEV_STATS_ADD(dev, rx_bytes, skb->len);
+		DEV_STATS_INC(dev, rx_packets);
 
 		consume_skb(local_skb);
 		consume_skb(skb);
@@ -336,7 +336,7 @@  static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
 	return NET_RX_SUCCESS;
 
 drop:
-	dev->stats.rx_dropped++;
+	DEV_STATS_INC(dev, rx_dropped);
 	return NET_RX_DROP;
 }
 
@@ -445,13 +445,13 @@  static int send_pkt(struct l2cap_chan *chan, struct sk_buff *skb,
 
 	err = l2cap_chan_send(chan, &msg, skb->len);
 	if (err > 0) {
-		netdev->stats.tx_bytes += err;
-		netdev->stats.tx_packets++;
+		DEV_STATS_ADD(netdev, tx_bytes, err);
+		DEV_STATS_INC(netdev, tx_packets);
 		return 0;
 	}
 
 	if (err < 0)
-		netdev->stats.tx_errors++;
+		DEV_STATS_INC(netdev, tx_errors);
 
 	return err;
 }