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/dropreason.h | 49 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 include/net/dropreason.h (limited to 'include/net/dropreason.h') diff --git a/include/net/dropreason.h b/include/net/dropreason.h new file mode 100644 index 000000000..1df60645f --- /dev/null +++ b/include/net/dropreason.h @@ -0,0 +1,49 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#ifndef _LINUX_DROPREASON_H +#define _LINUX_DROPREASON_H +#include + +/** + * enum skb_drop_reason_subsys - subsystem tag for (extended) drop reasons + */ +enum skb_drop_reason_subsys { + /** @SKB_DROP_REASON_SUBSYS_CORE: core drop reasons defined above */ + SKB_DROP_REASON_SUBSYS_CORE, + + /** + * @SKB_DROP_REASON_SUBSYS_MAC80211_UNUSABLE: mac80211 drop reasons + * for unusable frames, see net/mac80211/drop.h + */ + SKB_DROP_REASON_SUBSYS_MAC80211_UNUSABLE, + + /** + * @SKB_DROP_REASON_SUBSYS_OPENVSWITCH: openvswitch drop reasons, + * see net/openvswitch/drop.h + */ + SKB_DROP_REASON_SUBSYS_OPENVSWITCH, + + /** + * @SKB_DROP_REASON_SUBSYS_QDISC: TC qdisc drop reasons, + * see include/net/dropreason-qdisc.h + */ + SKB_DROP_REASON_SUBSYS_QDISC, + + /** @SKB_DROP_REASON_SUBSYS_NUM: number of subsystems defined */ + SKB_DROP_REASON_SUBSYS_NUM +}; + +struct drop_reason_list { + const char * const *reasons; + size_t n_reasons; +}; + +/* Note: due to dynamic registrations, access must be under RCU */ +extern const struct drop_reason_list __rcu * +drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_NUM]; + +void drop_reasons_register_subsys(enum skb_drop_reason_subsys subsys, + const struct drop_reason_list *list); +void drop_reasons_unregister_subsys(enum skb_drop_reason_subsys subsys); + +#endif -- cgit v1.3.1