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/psample.h | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 include/net/psample.h (limited to 'include/net/psample.h') diff --git a/include/net/psample.h b/include/net/psample.h new file mode 100644 index 000000000..5071b5fc2 --- /dev/null +++ b/include/net/psample.h @@ -0,0 +1,56 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __NET_PSAMPLE_H +#define __NET_PSAMPLE_H + +#include +#include + +struct psample_group { + struct list_head list; + struct net *net; + u32 group_num; + u32 refcount; + u32 seq; + struct rcu_head rcu; +}; + +struct psample_metadata { + u32 trunc_size; + int in_ifindex; + int out_ifindex; + u16 out_tc; + u64 out_tc_occ; /* bytes */ + u64 latency; /* nanoseconds */ + u8 out_tc_valid:1, + out_tc_occ_valid:1, + latency_valid:1, + rate_as_probability:1, + unused:4; + const u8 *user_cookie; + u32 user_cookie_len; +}; + +struct psample_group *psample_group_get(struct net *net, u32 group_num); +void psample_group_take(struct psample_group *group); +void psample_group_put(struct psample_group *group); + +struct sk_buff; + +#if IS_ENABLED(CONFIG_PSAMPLE) + +void psample_sample_packet(struct psample_group *group, + const struct sk_buff *skb, u32 sample_rate, + const struct psample_metadata *md); + +#else + +static inline void psample_sample_packet(struct psample_group *group, + const struct sk_buff *skb, + u32 sample_rate, + const struct psample_metadata *md) +{ +} + +#endif + +#endif /* __NET_PSAMPLE_H */ -- cgit v1.3.1