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 --- net/openvswitch/drop.h | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 net/openvswitch/drop.h (limited to 'net/openvswitch/drop.h') diff --git a/net/openvswitch/drop.h b/net/openvswitch/drop.h new file mode 100644 index 000000000..cedf9b7b5 --- /dev/null +++ b/net/openvswitch/drop.h @@ -0,0 +1,41 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * OpenvSwitch drop reason list. + */ + +#ifndef OPENVSWITCH_DROP_H +#define OPENVSWITCH_DROP_H +#include +#include + +#define OVS_DROP_REASONS(R) \ + R(OVS_DROP_LAST_ACTION) \ + R(OVS_DROP_ACTION_ERROR) \ + R(OVS_DROP_EXPLICIT) \ + R(OVS_DROP_EXPLICIT_WITH_ERROR) \ + R(OVS_DROP_METER) \ + R(OVS_DROP_RECURSION_LIMIT) \ + R(OVS_DROP_DEFERRED_LIMIT) \ + R(OVS_DROP_FRAG_L2_TOO_LONG) \ + R(OVS_DROP_FRAG_INVALID_PROTO) \ + R(OVS_DROP_CONNTRACK) \ + R(OVS_DROP_IP_TTL) \ + /* deliberate comment for trailing \ */ + +enum ovs_drop_reason { + __OVS_DROP_REASON = SKB_DROP_REASON_SUBSYS_OPENVSWITCH << + SKB_DROP_REASON_SUBSYS_SHIFT, +#define ENUM(x) x, + OVS_DROP_REASONS(ENUM) +#undef ENUM + + OVS_DROP_MAX, +}; + +static inline void +ovs_kfree_skb_reason(struct sk_buff *skb, enum ovs_drop_reason reason) +{ + kfree_skb_reason(skb, (u32)reason); +} + +#endif /* OPENVSWITCH_DROP_H */ -- cgit v1.3.1