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 --- drivers/char/nwbutton.h | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 drivers/char/nwbutton.h (limited to 'drivers/char/nwbutton.h') diff --git a/drivers/char/nwbutton.h b/drivers/char/nwbutton.h new file mode 100644 index 000000000..f2b9fdc1f --- /dev/null +++ b/drivers/char/nwbutton.h @@ -0,0 +1,40 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __NWBUTTON_H +#define __NWBUTTON_H + +/* + * NetWinder Button Driver- + * Copyright (C) Alex Holden 1998, 1999. + */ + +#ifdef __NWBUTTON_C /* Actually compiling the driver itself */ + +/* Various defines: */ + +#define NUM_PRESSES_REBOOT 2 /* How many presses to activate shutdown */ +#define BUTTON_DELAY 30 /* How many jiffies for sequence to end */ +#define VERSION "0.3" /* Driver version number */ + +/* Structure definitions: */ + +struct button_callback { + void (*callback) (void); + int count; +}; + +/* Function prototypes: */ + +static void button_sequence_finished(struct timer_list *unused); +static irqreturn_t button_handler (int irq, void *dev_id); +int button_init (void); +int button_add_callback (void (*callback) (void), int count); +int button_del_callback (void (*callback) (void)); +static void button_consume_callbacks (int bpcount); + +#else /* Not compiling the driver itself */ + +extern int button_add_callback (void (*callback) (void), int count); +extern int button_del_callback (void (*callback) (void)); + +#endif /* __NWBUTTON_C */ +#endif /* __NWBUTTON_H */ -- cgit v1.3.1