A/A Bonding: Skip sending GARPs when module unload is in progress

Commit 5f9bb24 ("rdmaip: Fix gratuitous ARP storm")
added a new work queue to send the GARP messages. During
module unload, the rdmaip_garps_wq is deleted and accessed
after that.  The following crash occurred during module unload
if one of the port is down.

Workqueue: rdmaip_garps 0xffffffffc0666a40
task: ffff8dea20ae97c0 task.stack: ffff9d6f4d3e8000
RIP: 0010:0xffffffffc0666a40
RSP: 0018:ffff9d6f4d3ebe60 EFLAGS: 00010202
RAX: ffffffffc0666a40 RBX: ffff8e209f523b00 RCX: ffff8e087faa2460
RDX: 0000000000000001 RSI: ffff8e209f523b00 RDI: ffff8e209f523b00
RBP: ffff9d6f4d3ebea0 R08: 0000000000000001 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000008 R12: ffff8dec4855c180
R13: ffff8e087faa2440 R14: ffffbd572028c200 R15: ffff8e209f523b08
FS:  0000000000000000(0000) GS:ffff8e087fa80000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffc0666a40 CR3: 000000097b40a004 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Call Trace:
 ? process_one_work+0x169/0x3a6
 worker_thread+0x4d/0x3e5
 kthread+0x105/0x138
 ? rescuer_thread+0x380/0x375
 ? kthread_bind+0x20/0x15
 ret_from_fork+0x3e/0x49
Code:  Bad RIP value.
RIP: 0xffffffffc0666a40 RSP: ffff9d6f4d3ebe60
CR2: ffffffffc0666a40

rdmaip_send_gratuitous_arp() function has been updated not to queue
any new work to the rdmaip_garps_wq work queue when module unload
is in progress.

Fixes: 5f9bb24 ("rdmaip: Fix gratuitous ARP storm")

Orabug: 29781216

Signed-off-by: Sudhakar Dindukurti <[email protected]>
Reviewed-by: Yuval Shaia <[email protected]>
Signed-off-by: Somasundaram Krishnasamy <[email protected]>

Author: sudhakar-dindukurti

drivers/infiniband/core/rdmaip.c

@@ -323,6 +323,19 @@ static void rdmaip_send_gratuitous_arp(struct net_device *out_dev,
 		RDMAIP_DBG2_PTR("Sending GARP message for adding IP addr %pI4 on %s\n",
 			       (void *)&ip_addr, out_dev->name);
 
+	/*
+	 * If module unload in progress, dont queue the work request to the
+	 * rdmaip_garps_wq.
+	 */
+	mutex_lock(&rdmaip_global_flag_lock);
+	if (rdmaip_is_teardown_flag_set()) {
+		RDMAIP_DBG2("%s: unload inprogress, dont queue GARP send\n",
+			    out_dev->name);
+		mutex_unlock(&rdmaip_global_flag_lock);
+		return;
+	}
+	mutex_unlock(&rdmaip_global_flag_lock);
+
 	if (rdmaip_active_bonding_arps_gap_ms == 0 ||
 	    rdmaip_active_bonding_arps_gap_ms > 100) {
 		pr_warn("arp gap (%d) out of range, using default (%d)\n",