From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- include/net/dsa_stubs.h | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 include/net/dsa_stubs.h (limited to 'include/net/dsa_stubs.h') diff --git a/include/net/dsa_stubs.h b/include/net/dsa_stubs.h new file mode 100644 index 000000000..6f384897f --- /dev/null +++ b/include/net/dsa_stubs.h @@ -0,0 +1,48 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * include/net/dsa_stubs.h - Stubs for the Distributed Switch Architecture framework + */ + +#include +#include +#include +#include + +#if IS_ENABLED(CONFIG_NET_DSA) + +extern const struct dsa_stubs *dsa_stubs; + +struct dsa_stubs { + int (*conduit_hwtstamp_validate)(struct net_device *dev, + const struct kernel_hwtstamp_config *config, + struct netlink_ext_ack *extack); +}; + +static inline int dsa_conduit_hwtstamp_validate(struct net_device *dev, + const struct kernel_hwtstamp_config *config, + struct netlink_ext_ack *extack) +{ + if (!netdev_uses_dsa(dev)) + return 0; + + /* rtnl_lock() is a sufficient guarantee, because as long as + * netdev_uses_dsa() returns true, the dsa_core module is still + * registered, and so, dsa_unregister_stubs() couldn't have run. + * For netdev_uses_dsa() to start returning false, it would imply that + * dsa_conduit_teardown() has executed, which requires rtnl_lock(). + */ + ASSERT_RTNL(); + + return dsa_stubs->conduit_hwtstamp_validate(dev, config, extack); +} + +#else + +static inline int dsa_conduit_hwtstamp_validate(struct net_device *dev, + const struct kernel_hwtstamp_config *config, + struct netlink_ext_ack *extack) +{ + return 0; +} + +#endif -- cgit v1.3.1