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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: CsbJUVZzEgo9CV+aff5KWosB30izHtFsPAo7b67ijy89QiaHmwgn3+Su5O/pwCEjHvOnLVkkw99PX8t65gBGd0GIBNOVmAQUZ01QVT4fCI+zlkd0nFhT2bXh9Dd37UOhP45bAszpzp8tDoagO9+AFHjNXGI2fPSaCmod45fisORPYo/dvstvEwC8so23i2pCVrtOtyQZ+Ht08tHx2sMVNLVNHbJFu5q4xfTJckFPhADqoGsnoYXedheT4iP39Bv6SNqqlB0NdGLMbIDKuupTo+4CWY4NHJOOJ72+xzEiOvGQdKKo0gxVcJ9tmD3YAOQk2s9XtM6+YJD4v9fP7ATWarec91nNESsBvHZZTFVwbMAOrEc6UECPwv6WDpx278b9ZUurcA8uMH/jjF5bTsX7OWGvCDbfBtAKg8s7aW1MI5AmakzvuzZ2rBXpzaKkm+Zf X-OriginatorOrg: ti.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 24 Feb 2026 12:22:54.6780 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 62cb82e1-52a1-4d0c-c592-08de739f6fe4 X-MS-Exchange-CrossTenant-Id: e5b49634-450b-4709-8abb-1e2b19b982b7 X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=e5b49634-450b-4709-8abb-1e2b19b982b7;Ip=[198.47.21.194];Helo=[flwvzet200.ext.ti.com] X-MS-Exchange-CrossTenant-AuthSource: SA2PEPF000015C7.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: BLAPR10MB5156 On Mon, 2026-02-23 at 18:48 -0800, Jakub Kicinski wrote: > On Fri, 20 Feb 2026 09:41:58 +0530 Siddharth Vadapalli wrote: > > The 'irq_disabled' variable indicates the current state of the TX IRQ a= nd > > is used by the TX NAPI handler to determine whether the IRQ should be > > enabled. > >=20 > > Currently, 'irq_disabled' is set before actually disabling the IRQ by > > invoking disable_irq_nosync(). In an SMP environment, this leads to a r= ace > > condition wherein the processor taking the interrupt sets 'irq_disabled= ' > > while another processor executing a previous instance of the TX NAPI > > handler sees 'irq_disabled' set and invokes enable_irq() before the TX = IRQ > > is actually disabled by disable_irq_nosync(). This results in the follo= wing > > warning: > > Unbalanced enable for IRQ ... >=20 > AFAICT the flow on the Tx bug is not buggy, owner ship of the IRQ > vector passes handler -> NAPI -> timer. I don't see how those can > race. The issue is seen in practice. Interrupt coalescing (hrtimer) isn't used. The call sequence leading to the warning is: net_rx_action __napi_poll NAPI TX Handler It does seem strange that the 'net_rx_action' leads to the NAPI TX Handler. However, it is exactly this path that causes the warning, and it is due to this that we could end up in the following situation: CPU0 =09 CPU1 ---------------- -------------- 1. TX HARD IRQ Handler entered NAPI TX Handler is running 2. irq_disabled is set Sees irq_disabled being set 3. Starts executing disable_irq_nosync() Invokes enable_irq() for TX IRQ before its really disabled =09 [UNBALANCED IRQ WARNING IS DISPLAYED] Regards, Siddharth.