From: Nikhil P. Rao Date: Tue, 14 Jul 2026 18:02:23 +0000 (+0000) Subject: pds_core: fix use-after-free on workqueue during remove X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=0ad134881508c36b65c1a8864f8bec53adbd3327;p=thirdparty%2Fkernel%2Flinux.git pds_core: fix use-after-free on workqueue during remove In pdsc_remove(), the workqueue is destroyed before pdsc_teardown() is called. This ordering allows two paths to queue work on the destroyed workqueue: 1. If pdsc_teardown() -> pdsc_devcmd_reset() times out, the error path in pdsc_devcmd_locked() queues health_work. 2. A NotifyQ event can trigger the ISR and queue work before free_irq() is called in pdsc_teardown(). Fix by moving destroy_workqueue() after pdsc_teardown() so the workqueue outlives every queuer; destroy_workqueue() then flushes any work still pending. Draining the queued work also requires ordering the teardown so the resources that work touches are freed last: - In pdsc_qcq_free(), after freeing the interrupt, cancel_work_sync() the queue's work and only then clear qcq->intx, so pdsc_process_adminq()'s read of qcq->intx for interrupt-credit return cannot race with the clear. - Free adminqcq before notifyqcq: the shared adminq ISR is released when adminqcq is freed, and the adminq work accesses notifyqcq, so both must be stopped before notifyqcq is freed. Fixes: 01ba61b55b20 ("pds_core: Add adminq processing and commands") Reported-by: sashiko-bot Closes: https://patchwork.kernel.org/comment/27002369/ Signed-off-by: Nikhil P. Rao Link: https://patch.msgid.link/20260714180223.1642792-3-nikhil.rao@amd.com Signed-off-by: Jakub Kicinski --- diff --git a/drivers/net/ethernet/amd/pds_core/core.c b/drivers/net/ethernet/amd/pds_core/core.c index 1074a022a52f..e39b2c9beb20 100644 --- a/drivers/net/ethernet/amd/pds_core/core.c +++ b/drivers/net/ethernet/amd/pds_core/core.c @@ -110,7 +110,6 @@ static void pdsc_qcq_intr_free(struct pdsc *pdsc, struct pdsc_qcq *qcq) return; pdsc_intr_free(pdsc, qcq->intx); - qcq->intx = PDS_CORE_INTR_INDEX_NOT_ASSIGNED; } static int pdsc_qcq_intr_alloc(struct pdsc *pdsc, struct pdsc_qcq *qcq) @@ -145,6 +144,12 @@ void pdsc_qcq_free(struct pdsc *pdsc, struct pdsc_qcq *qcq) pdsc_qcq_intr_free(pdsc, qcq); + /* Drain any work queued by ISR before it was freed above */ + if (qcq->work.func) + cancel_work_sync(&qcq->work); + + qcq->intx = PDS_CORE_INTR_INDEX_NOT_ASSIGNED; + if (qcq->q_base) dma_free_coherent(dev, qcq->q_size, qcq->q_base, qcq->q_base_pa); @@ -304,8 +309,11 @@ err_out: static void pdsc_core_uninit(struct pdsc *pdsc) { - pdsc_qcq_free(pdsc, &pdsc->notifyqcq); + /* Free adminqcq first: its work accesses notifyqcq, so we must + * disable its IRQ and drain its work before freeing notifyqcq. + */ pdsc_qcq_free(pdsc, &pdsc->adminqcq); + pdsc_qcq_free(pdsc, &pdsc->notifyqcq); if (pdsc->kern_dbpage) { iounmap(pdsc->kern_dbpage); @@ -479,8 +487,6 @@ void pdsc_teardown(struct pdsc *pdsc, bool removing) { if (!pdsc->pdev->is_virtfn) pdsc_devcmd_reset(pdsc); - if (pdsc->adminqcq.work.func) - cancel_work_sync(&pdsc->adminqcq.work); pci_clear_master(pdsc->pdev); diff --git a/drivers/net/ethernet/amd/pds_core/main.c b/drivers/net/ethernet/amd/pds_core/main.c index 22db78343eb0..638b9c7a509d 100644 --- a/drivers/net/ethernet/amd/pds_core/main.c +++ b/drivers/net/ethernet/amd/pds_core/main.c @@ -435,8 +435,6 @@ static void pdsc_remove(struct pci_dev *pdev) pdsc_auxbus_dev_del(pdsc, pdsc, &pdsc->padev); timer_shutdown_sync(&pdsc->wdtimer); - if (pdsc->wq) - destroy_workqueue(pdsc->wq); mutex_lock(&pdsc->config_lock); set_bit(PDSC_S_STOPPING_DRIVER, &pdsc->state); @@ -444,6 +442,9 @@ static void pdsc_remove(struct pci_dev *pdev) pdsc_stop(pdsc); pdsc_teardown(pdsc, PDSC_TEARDOWN_REMOVING); mutex_unlock(&pdsc->config_lock); + + if (pdsc->wq) + destroy_workqueue(pdsc->wq); mutex_destroy(&pdsc->config_lock); mutex_destroy(&pdsc->devcmd_lock);