A potential race condition exists in mana_hwc_destroy_channel() where hwc->caller_ctx is freed before the HWC's Completion Queue (CQ) and Event Queue (EQ) are destroyed. This allows an in-flight CQ interrupt handler to dereference freed memory, leading to a use-after-free or NULL pointer dereference in mana_hwc_handle_resp(). mana_smc_teardown_hwc() signals the hardware to stop but does not synchronize against IRQ handlers already executing on other CPUs. The IRQ synchronization only happens in mana_hwc_destroy_cq() via mana_gd_destroy_eq() -> mana_gd_deregister_irq(). Since this runs after kfree(hwc->caller_ctx), a concurrent mana_hwc_rx_event_handler() can dereference freed caller_ctx (and rxq->msg_buf) in mana_hwc_handle_resp(). Fix this by reordering teardown to reverse-of-creation order: destroy the TX/RX work queues and CQ/EQ before freeing hwc->caller_ctx. This ensures all in-flight interrupt handlers complete before the memory they access is freed. Fixes: ca9c54d2d6a5 ("net: mana: Add a driver for Microsoft Azure Network Adapter (MANA)") Reviewed-by: Haiyang Zhang Signed-off-by: Dipayaan Roy --- drivers/net/ethernet/microsoft/mana/hw_channel.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/microsoft/mana/hw_channel.c b/drivers/net/ethernet/microsoft/mana/hw_channel.c index 91975bdb5686..dbbde0fa57e7 100644 --- a/drivers/net/ethernet/microsoft/mana/hw_channel.c +++ b/drivers/net/ethernet/microsoft/mana/hw_channel.c @@ -814,9 +814,6 @@ void mana_hwc_destroy_channel(struct gdma_context *gc) gc->max_num_cqs = 0; } - kfree(hwc->caller_ctx); - hwc->caller_ctx = NULL; - if (hwc->txq) mana_hwc_destroy_wq(hwc, hwc->txq); @@ -826,6 +823,9 @@ void mana_hwc_destroy_channel(struct gdma_context *gc) if (hwc->cq) mana_hwc_destroy_cq(hwc->gdma_dev->gdma_context, hwc->cq); + kfree(hwc->caller_ctx); + hwc->caller_ctx = NULL; + mana_gd_free_res_map(&hwc->inflight_msg_res); hwc->num_inflight_msg = 0; -- 2.43.0