From f41c538881eec4dcf5961a242097d447f848cda6 Mon Sep 17 00:00:00 2001 From: Yi Sun Date: Tue, 29 Jul 2025 23:03:12 +0800 Subject: dmaengine: idxd: Remove improper idxd_free The call to idxd_free() introduces a duplicate put_device() leading to a reference count underflow: refcount_t: underflow; use-after-free. WARNING: CPU: 15 PID: 4428 at lib/refcount.c:28 refcount_warn_saturate+0xbe/0x110 ... Call Trace: idxd_remove+0xe4/0x120 [idxd] pci_device_remove+0x3f/0xb0 device_release_driver_internal+0x197/0x200 driver_detach+0x48/0x90 bus_remove_driver+0x74/0xf0 pci_unregister_driver+0x2e/0xb0 idxd_exit_module+0x34/0x7a0 [idxd] __do_sys_delete_module.constprop.0+0x183/0x280 do_syscall_64+0x54/0xd70 entry_SYSCALL_64_after_hwframe+0x76/0x7e The idxd_unregister_devices() which is invoked at the very beginning of idxd_remove(), already takes care of the necessary put_device() through the following call path: idxd_unregister_devices() -> device_unregister() -> put_device() In addition, when CONFIG_DEBUG_KOBJECT_RELEASE is enabled, put_device() may trigger asynchronous cleanup via schedule_delayed_work(). If idxd_free() is called immediately after, it can result in a use-after-free. Remove the improper idxd_free() to avoid both the refcount underflow and potential memory corruption during module unload. Fixes: d5449ff1b04d ("dmaengine: idxd: Add missing idxd cleanup to fix memory leak in remove call") Signed-off-by: Yi Sun Tested-by: Shuai Xue Reviewed-by: Dave Jiang Acked-by: Vinicius Costa Gomes Link: https://lore.kernel.org/r/20250729150313.1934101-2-yi.sun@intel.com Signed-off-by: Vinod Koul --- drivers/dma/idxd/init.c | 1 - 1 file changed, 1 deletion(-) (limited to 'drivers/dma/idxd/init.c') diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c index 35bdefd3728b..487268fc527b 100644 --- a/drivers/dma/idxd/init.c +++ b/drivers/dma/idxd/init.c @@ -1294,7 +1294,6 @@ static void idxd_remove(struct pci_dev *pdev) idxd_cleanup(idxd); pci_iounmap(pdev, idxd->reg_base); put_device(idxd_confdev(idxd)); - idxd_free(idxd); pci_disable_device(pdev); } -- cgit v1.2.3 From b7cb9a034305d52222433fad10c3de10204f29e7 Mon Sep 17 00:00:00 2001 From: Yi Sun Date: Tue, 29 Jul 2025 23:03:13 +0800 Subject: dmaengine: idxd: Fix refcount underflow on module unload A recent refactor introduced a misplaced put_device() call, resulting in a reference count underflow during module unload. There is no need to add additional put_device() calls for idxd groups, engines, or workqueues. Although the commit claims: "Note, this also fixes the missing put_device() for idxd groups, engines, and wqs." It appears no such omission actually existed. The required cleanup is already handled by the call chain: idxd_unregister_devices() -> device_unregister() -> put_device() Extend idxd_cleanup() to handle the remaining necessary cleanup and remove idxd_cleanup_internals(), which duplicates deallocation logic for idxd, engines, groups, and workqueues. Memory management is also properly handled through the Linux device model. Fixes: a409e919ca32 ("dmaengine: idxd: Refactor remove call with idxd_cleanup() helper") Signed-off-by: Yi Sun Tested-by: Shuai Xue Reviewed-by: Dave Jiang Acked-by: Vinicius Costa Gomes Link: https://lore.kernel.org/r/20250729150313.1934101-3-yi.sun@intel.com Signed-off-by: Vinod Koul --- drivers/dma/idxd/init.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'drivers/dma/idxd/init.c') diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c index 487268fc527b..efe614a528fa 100644 --- a/drivers/dma/idxd/init.c +++ b/drivers/dma/idxd/init.c @@ -1291,7 +1291,10 @@ static void idxd_remove(struct pci_dev *pdev) device_unregister(idxd_confdev(idxd)); idxd_shutdown(pdev); idxd_device_remove_debugfs(idxd); - idxd_cleanup(idxd); + perfmon_pmu_remove(idxd); + idxd_cleanup_interrupts(idxd); + if (device_pasid_enabled(idxd)) + idxd_disable_system_pasid(idxd); pci_iounmap(pdev, idxd->reg_base); put_device(idxd_confdev(idxd)); pci_disable_device(pdev); -- cgit v1.2.3 From 39aaa337449e71a41d4813be0226a722827ba606 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Mon, 11 Aug 2025 13:43:39 +0300 Subject: dmaengine: idxd: Fix double free in idxd_setup_wqs() The clean up in idxd_setup_wqs() has had a couple bugs because the error handling is a bit subtle. It's simpler to just re-write it in a cleaner way. The issues here are: 1) If "idxd->max_wqs" is <= 0 then we call put_device(conf_dev) when "conf_dev" hasn't been initialized. 2) If kzalloc_node() fails then again "conf_dev" is invalid. It's either uninitialized or it points to the "conf_dev" from the previous iteration so it leads to a double free. It's better to free partial loop iterations within the loop and then the unwinding at the end can handle whole loop iterations. I also renamed the labels to describe what the goto does and not where the goto was located. Fixes: 3fd2f4bc010c ("dmaengine: idxd: fix memory leak in error handling path of idxd_setup_wqs") Reported-by: Colin Ian King Closes: https://lore.kernel.org/all/20250811095836.1642093-1-colin.i.king@gmail.com/ Signed-off-by: Dan Carpenter Reviewed-by: Dave Jiang Link: https://lore.kernel.org/r/aJnJW3iYTDDCj9sk@stanley.mountain Signed-off-by: Vinod Koul --- drivers/dma/idxd/init.c | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-) (limited to 'drivers/dma/idxd/init.c') diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c index efe614a528fa..8c4725ad1f64 100644 --- a/drivers/dma/idxd/init.c +++ b/drivers/dma/idxd/init.c @@ -189,27 +189,30 @@ static int idxd_setup_wqs(struct idxd_device *idxd) idxd->wq_enable_map = bitmap_zalloc_node(idxd->max_wqs, GFP_KERNEL, dev_to_node(dev)); if (!idxd->wq_enable_map) { rc = -ENOMEM; - goto err_bitmap; + goto err_free_wqs; } for (i = 0; i < idxd->max_wqs; i++) { wq = kzalloc_node(sizeof(*wq), GFP_KERNEL, dev_to_node(dev)); if (!wq) { rc = -ENOMEM; - goto err; + goto err_unwind; } idxd_dev_set_type(&wq->idxd_dev, IDXD_DEV_WQ); conf_dev = wq_confdev(wq); wq->id = i; wq->idxd = idxd; - device_initialize(wq_confdev(wq)); + device_initialize(conf_dev); conf_dev->parent = idxd_confdev(idxd); conf_dev->bus = &dsa_bus_type; conf_dev->type = &idxd_wq_device_type; rc = dev_set_name(conf_dev, "wq%d.%d", idxd->id, wq->id); - if (rc < 0) - goto err; + if (rc < 0) { + put_device(conf_dev); + kfree(wq); + goto err_unwind; + } mutex_init(&wq->wq_lock); init_waitqueue_head(&wq->err_queue); @@ -220,15 +223,20 @@ static int idxd_setup_wqs(struct idxd_device *idxd) wq->enqcmds_retries = IDXD_ENQCMDS_RETRIES; wq->wqcfg = kzalloc_node(idxd->wqcfg_size, GFP_KERNEL, dev_to_node(dev)); if (!wq->wqcfg) { + put_device(conf_dev); + kfree(wq); rc = -ENOMEM; - goto err; + goto err_unwind; } if (idxd->hw.wq_cap.op_config) { wq->opcap_bmap = bitmap_zalloc(IDXD_MAX_OPCAP_BITS, GFP_KERNEL); if (!wq->opcap_bmap) { + kfree(wq->wqcfg); + put_device(conf_dev); + kfree(wq); rc = -ENOMEM; - goto err_opcap_bmap; + goto err_unwind; } bitmap_copy(wq->opcap_bmap, idxd->opcap_bmap, IDXD_MAX_OPCAP_BITS); } @@ -239,13 +247,7 @@ static int idxd_setup_wqs(struct idxd_device *idxd) return 0; -err_opcap_bmap: - kfree(wq->wqcfg); - -err: - put_device(conf_dev); - kfree(wq); - +err_unwind: while (--i >= 0) { wq = idxd->wqs[i]; if (idxd->hw.wq_cap.op_config) @@ -254,11 +256,10 @@ err: conf_dev = wq_confdev(wq); put_device(conf_dev); kfree(wq); - } bitmap_free(idxd->wq_enable_map); -err_bitmap: +err_free_wqs: kfree(idxd->wqs); return rc; -- cgit v1.2.3