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 --- rust/helpers/task.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 rust/helpers/task.c (limited to 'rust/helpers/task.c') diff --git a/rust/helpers/task.c b/rust/helpers/task.c new file mode 100644 index 000000000..b46b1433a --- /dev/null +++ b/rust/helpers/task.c @@ -0,0 +1,57 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include + +__rust_helper void rust_helper_might_resched(void) +{ + might_resched(); +} + +__rust_helper struct task_struct *rust_helper_get_current(void) +{ + return current; +} + +__rust_helper void rust_helper_get_task_struct(struct task_struct *t) +{ + get_task_struct(t); +} + +__rust_helper void rust_helper_put_task_struct(struct task_struct *t) +{ + put_task_struct(t); +} + +__rust_helper kuid_t rust_helper_task_uid(struct task_struct *task) +{ + return task_uid(task); +} + +#ifndef CONFIG_USER_NS +__rust_helper uid_t rust_helper_from_kuid(struct user_namespace *to, kuid_t uid) +{ + return from_kuid(to, uid); +} +#endif /* CONFIG_USER_NS */ + +__rust_helper bool rust_helper_uid_eq(kuid_t left, kuid_t right) +{ + return uid_eq(left, right); +} + +__rust_helper kuid_t rust_helper_current_euid(void) +{ + return current_euid(); +} + +__rust_helper struct user_namespace *rust_helper_current_user_ns(void) +{ + return current_user_ns(); +} + +__rust_helper pid_t rust_helper_task_tgid_nr_ns(struct task_struct *tsk, + struct pid_namespace *ns) +{ + return task_tgid_nr_ns(tsk, ns); +} -- cgit v1.3.1