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/batman-adv/bitarray.h | 56 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 net/batman-adv/bitarray.h (limited to 'net/batman-adv/bitarray.h') diff --git a/net/batman-adv/bitarray.h b/net/batman-adv/bitarray.h new file mode 100644 index 000000000..2b9f5dbb3 --- /dev/null +++ b/net/batman-adv/bitarray.h @@ -0,0 +1,56 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) B.A.T.M.A.N. contributors: + * + * Simon Wunderlich, Marek Lindner + */ + +#ifndef _NET_BATMAN_ADV_BITARRAY_H_ +#define _NET_BATMAN_ADV_BITARRAY_H_ + +#include "main.h" + +#include +#include +#include +#include + +/** + * batadv_test_bit() - check if bit is set in the current window + * + * @seq_bits: pointer to the sequence number bitmap of received packets + * @last_seqno: latest sequence number in seq_bits + * @curr_seqno: sequence number to test for + * + * Return: true if the corresponding bit in the given seq_bits indicates true + * and curr_seqno is within range of last_seqno. Otherwise returns false. + */ +static inline bool batadv_test_bit(const unsigned long *seq_bits, + u32 last_seqno, u32 curr_seqno) +{ + s32 diff; + + diff = last_seqno - curr_seqno; + if (diff < 0 || diff >= BATADV_TQ_LOCAL_WINDOW_SIZE) + return false; + return test_bit(diff, seq_bits) != 0; +} + +/** + * batadv_set_bit() - Turn corresponding bit on, so we can remember that we got + * the packet + * @seq_bits: bitmap of the packet receive window + * @n: relative sequence number of newly received packet + */ +static inline void batadv_set_bit(unsigned long *seq_bits, s32 n) +{ + /* if too old, just drop it */ + if (n < 0 || n >= BATADV_TQ_LOCAL_WINDOW_SIZE) + return; + + set_bit(n, seq_bits); /* turn the position on */ +} + +bool batadv_bit_get_packet(void *priv, unsigned long *seq_bits, + s32 seq_num_diff, int set_mark); + +#endif /* _NET_BATMAN_ADV_BITARRAY_H_ */ -- cgit v1.3.1