Thread (15 messages) 15 messages, 5 authors, 2024-08-30

Re: [Intel-wired-lan] [[PATCH v2 iwl-next] v2 1/4] idpf: address an rtnl lock splat in tx timeout recovery path

From: Jacob Keller <jacob.e.keller@intel.com>
Date: 2024-08-28 21:28:24
Also in: intel-wired-lan, lkml


On 8/26/2024 11:10 AM, Manoj Vishwanathan wrote:
quoted hunk ↗ jump to hunk
From: David Decotigny <redacted>

Adopt the same pattern as in other places in the code to take the rtnl
lock during hard resets.
Tested the patch by injecting tx timeout in IDPF , observe that idpf
recovers and IDPF comes back reachable

Without this patch causes there is a splat:
[  270.145214] WARNING: CPU:  PID:  at net/sched/sch_generic.c:534 dev_watchdog

Fixes: d4d5587182664 (idpf: initialize interrupts and enable vport)
Signed-off-by: Manoj Vishwanathan <redacted>
---
 drivers/net/ethernet/intel/idpf/idpf_txrx.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/intel/idpf/idpf_txrx.c b/drivers/net/ethernet/intel/idpf/idpf_txrx.c
index af2879f03b8d..806a8b6ea5c5 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_txrx.c
+++ b/drivers/net/ethernet/intel/idpf/idpf_txrx.c
@@ -4326,6 +4326,7 @@ int idpf_vport_intr_alloc(struct idpf_vport *vport)
  */
 int idpf_vport_intr_init(struct idpf_vport *vport)
 {
+	bool hr_reset_in_prog;
 	char *int_name;
 	int err;
 
@@ -4334,8 +4335,19 @@ int idpf_vport_intr_init(struct idpf_vport *vport)
 		return err;
 
 	idpf_vport_intr_map_vector_to_qs(vport);
+	/** 
+	 * If we're in normal up path, the stack already takes the
+	 * rtnl_lock for us, however, if we're doing up as a part of a
+	 * hard reset, we'll need to take the lock ourself before
+	 * touching the netdev.
+	 */
+	hr_reset_in_prog = test_bit(IDPF_HR_RESET_IN_PROG,
+					vport->adapter->flags);
+	if (hr_reset_in_prog)
+		rtnl_lock();
 	idpf_vport_intr_napi_add_all(vport);
-
+	if (hr_reset_in_prog)
+		rtnl_unlock();
This feels a little fragile. Why not pass the reset in progress as a
flag from the caller? Surely the caller knows whether this is happening
due to an interface up or due to a reset?
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