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 --- io_uring/query.c | 155 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 155 insertions(+) create mode 100644 io_uring/query.c (limited to 'io_uring/query.c') diff --git a/io_uring/query.c b/io_uring/query.c new file mode 100644 index 000000000..7bce2ec16 --- /dev/null +++ b/io_uring/query.c @@ -0,0 +1,155 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "linux/io_uring/query.h" + +#include "query.h" +#include "io_uring.h" +#include "zcrx.h" + +union io_query_data { + struct io_uring_query_opcode opcodes; + struct io_uring_query_zcrx zcrx; + struct io_uring_query_zcrx_event zcrx_notif; + struct io_uring_query_scq scq; +}; + +#define IO_MAX_QUERY_SIZE sizeof(union io_query_data) +#define IO_MAX_QUERY_ENTRIES 1000 + +static ssize_t io_query_ops(union io_query_data *data) +{ + struct io_uring_query_opcode *e = &data->opcodes; + + e->nr_request_opcodes = IORING_OP_LAST; + e->nr_register_opcodes = IORING_REGISTER_LAST; + e->feature_flags = IORING_FEAT_FLAGS; + e->ring_setup_flags = IORING_SETUP_FLAGS; + e->enter_flags = IORING_ENTER_FLAGS; + e->sqe_flags = SQE_VALID_FLAGS; + e->nr_query_opcodes = __IO_URING_QUERY_MAX; + e->__pad = 0; + return sizeof(*e); +} + +static ssize_t io_query_zcrx(union io_query_data *data) +{ + struct io_uring_query_zcrx *e = &data->zcrx; + + e->register_flags = ZCRX_SUPPORTED_REG_FLAGS; + e->area_flags = IORING_ZCRX_AREA_DMABUF; + e->nr_ctrl_opcodes = __ZCRX_CTRL_LAST; + e->rq_hdr_size = sizeof(struct zcrx_rq_hdr); + e->rq_hdr_alignment = L1_CACHE_BYTES; + e->features = ZCRX_FEATURES; + e->__resv2 = 0; + return sizeof(*e); +} + +static ssize_t io_query_zcrx_notif(union io_query_data *data) +{ + struct io_uring_query_zcrx_event *e = &data->zcrx_notif; + + e->event_flags = ZCRX_EVENT_TYPE_MASK; + e->stats_size = sizeof(struct zcrx_stats); + e->stats_off_alignment = __alignof__(struct zcrx_stats); + e->__resv1 = 0; + memset(&e->__resv2, 0, sizeof(e->__resv2)); + return sizeof(*e); +} + +static ssize_t io_query_scq(union io_query_data *data) +{ + struct io_uring_query_scq *e = &data->scq; + + e->hdr_size = sizeof(struct io_rings); + e->hdr_alignment = SMP_CACHE_BYTES; + return sizeof(*e); +} + +static int io_handle_query_entry(union io_query_data *data, void __user *uhdr, + u64 *next_entry) +{ + struct io_uring_query_hdr hdr; + size_t usize, res_size = 0; + ssize_t ret = -EINVAL; + void __user *udata; + + if (copy_from_user(&hdr, uhdr, sizeof(hdr))) + return -EFAULT; + /* copy_struct_to_user() zeros up to usize bytes */ + if (hdr.size > PAGE_SIZE) + return -E2BIG; + usize = hdr.size; + hdr.size = min(hdr.size, IO_MAX_QUERY_SIZE); + udata = u64_to_user_ptr(hdr.query_data); + + if (hdr.query_op >= __IO_URING_QUERY_MAX) { + ret = -EOPNOTSUPP; + goto out; + } + if (!mem_is_zero(hdr.__resv, sizeof(hdr.__resv)) || hdr.result || !hdr.size) + goto out; + if (copy_from_user(data, udata, hdr.size)) + return -EFAULT; + + switch (hdr.query_op) { + case IO_URING_QUERY_OPCODES: + ret = io_query_ops(data); + break; + case IO_URING_QUERY_ZCRX: + ret = io_query_zcrx(data); + break; + case IO_URING_QUERY_ZCRX_EVENT: + ret = io_query_zcrx_notif(data); + break; + case IO_URING_QUERY_SCQ: + ret = io_query_scq(data); + break; + } + + if (ret >= 0) { + if (WARN_ON_ONCE(ret > IO_MAX_QUERY_SIZE)) + return -EFAULT; + res_size = ret; + ret = 0; + } +out: + hdr.result = ret; + hdr.size = min_t(size_t, usize, res_size); + + if (copy_struct_to_user(udata, usize, data, hdr.size, NULL)) + return -EFAULT; + if (copy_to_user(uhdr, &hdr, sizeof(hdr))) + return -EFAULT; + *next_entry = hdr.next_entry; + return 0; +} + +int io_query(void __user *arg, unsigned nr_args) +{ + union io_query_data entry_buffer; + void __user *uhdr = arg; + int ret, nr = 0; + + memset(&entry_buffer, 0, sizeof(entry_buffer)); + + if (nr_args) + return -EINVAL; + + while (uhdr) { + u64 next_hdr; + + ret = io_handle_query_entry(&entry_buffer, uhdr, &next_hdr); + if (ret) + return ret; + uhdr = u64_to_user_ptr(next_hdr); + + /* Have some limit to avoid a potential cycle */ + if (++nr >= IO_MAX_QUERY_ENTRIES) + return -ERANGE; + if (fatal_signal_pending(current)) + return -EINTR; + cond_resched(); + } + return 0; +} -- cgit v1.3.1