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/tty/tty_mutex.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) create mode 100644 drivers/tty/tty_mutex.c (limited to 'drivers/tty/tty_mutex.c') diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c new file mode 100644 index 000000000..784e46a0a --- /dev/null +++ b/drivers/tty/tty_mutex.c @@ -0,0 +1,55 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include "tty.h" + +/* Legacy tty mutex glue */ + +/* + * Getting the big tty mutex. + */ + +void tty_lock(struct tty_struct *tty) +{ + tty_kref_get(tty); + mutex_lock(&tty->legacy_mutex); +} +EXPORT_SYMBOL(tty_lock); + +int tty_lock_interruptible(struct tty_struct *tty) +{ + int ret; + + tty_kref_get(tty); + ret = mutex_lock_interruptible(&tty->legacy_mutex); + if (ret) + tty_kref_put(tty); + return ret; +} + +void tty_unlock(struct tty_struct *tty) +{ + mutex_unlock(&tty->legacy_mutex); + tty_kref_put(tty); +} +EXPORT_SYMBOL(tty_unlock); + +void tty_lock_slave(struct tty_struct *tty) +{ + if (tty && tty != tty->link) + tty_lock(tty); +} + +void tty_unlock_slave(struct tty_struct *tty) +{ + if (tty && tty != tty->link) + tty_unlock(tty); +} + +void tty_set_lock_subclass(struct tty_struct *tty) +{ + lockdep_set_subclass(&tty->legacy_mutex, TTY_LOCK_SLAVE); +} -- cgit v1.3.1