[PATCH v2] Bluetooth: 6lowpan: use DEV_STAT_INC() to avoid races

[PATCH v2] Bluetooth: 6lowpan: use DEV_STAT_INC() to avoid races

[yunshui]

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 <jiangyunshui@kylinos.cn>
---
 net/bluetooth/6lowpan.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index 50cfec8ccac4..b8906f55e2b2 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 +336,8 @@ 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 +446,13 @@ 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;
 }
-- 
2.34.1

Re: [PATCH v2] Bluetooth: 6lowpan: use DEV_STAT_INC() to avoid races

[Paul Menzel]

Dear yunshui,


Thank you for your patch. One formal request:

Am 27.05.24 um 08:52 schrieb yunshui:
> 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 <jiangyunshui@kylinos.cn>

Could you please use your full name? Maybe:

     $ git config --global user.name "Jiang Yunshui"
     $ git commit --amend --author="Jiang Yunshui <jiangyunshui@kylinos.cn>"

[…]


Kind regards,

Paul

RE: [v2] Bluetooth: 6lowpan: use DEV_STAT_INC() to avoid races

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 2578 bytes --]

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=856029

---Test result---

Test Summary:
CheckPatch                    PASS      1.48 seconds
GitLint                       PASS      0.28 seconds
SubjectPrefix                 PASS      0.09 seconds
BuildKernel                   PASS      30.17 seconds
CheckAllWarning               PASS      33.30 seconds
CheckSparse                   PASS      38.45 seconds
CheckSmatch                   FAIL      38.05 seconds
BuildKernel32                 PASS      28.90 seconds
TestRunnerSetup               PASS      523.54 seconds
TestRunner_l2cap-tester       PASS      20.42 seconds
TestRunner_iso-tester         FAIL      32.55 seconds
TestRunner_bnep-tester        PASS      4.88 seconds
TestRunner_mgmt-tester        PASS      114.01 seconds
TestRunner_rfcomm-tester      PASS      8.52 seconds
TestRunner_sco-tester         PASS      15.01 seconds
TestRunner_ioctl-tester       PASS      7.88 seconds
TestRunner_mesh-tester        PASS      6.11 seconds
TestRunner_smp-tester         PASS      6.94 seconds
TestRunner_userchan-tester    PASS      5.07 seconds
IncrementalBuild              PASS      27.55 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
##############################
Test: TestRunner_iso-tester - FAIL
Desc: Run iso-tester with test-runner
Output:
Total: 122, Passed: 117 (95.9%), Failed: 1, Not Run: 4

Failed Test Cases
ISO Connect Suspend - Success                        Failed       4.178 seconds


---
Regards,
Linux Bluetooth