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 --- Documentation/driver-api/miscellaneous.rst | 48 ++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 Documentation/driver-api/miscellaneous.rst (limited to 'Documentation/driver-api/miscellaneous.rst') diff --git a/Documentation/driver-api/miscellaneous.rst b/Documentation/driver-api/miscellaneous.rst new file mode 100644 index 000000000..4a5104a36 --- /dev/null +++ b/Documentation/driver-api/miscellaneous.rst @@ -0,0 +1,48 @@ +Parallel Port Devices +===================== + +.. kernel-doc:: include/linux/parport.h + :internal: + +.. kernel-doc:: drivers/parport/ieee1284.c + :export: + +.. kernel-doc:: drivers/parport/share.c + :export: + +.. kernel-doc:: drivers/parport/daisy.c + :internal: + +16x50 UART Driver +================= + +.. kernel-doc:: drivers/tty/serial/8250/8250_core.c + :export: + +See serial/driver.rst for related APIs. + +Pulse-Width Modulation (PWM) +============================ + +Pulse-width modulation is a modulation technique primarily used to +control power supplied to electrical devices. + +The PWM framework provides an abstraction for providers and consumers of +PWM signals. A controller that provides one or more PWM signals is +registered as :c:type:`struct pwm_chip `. Providers +are expected to embed this structure in a driver-specific structure. +This structure contains fields that describe a particular chip. + +A chip exposes one or more PWM signal sources, each of which exposed as +a :c:type:`struct pwm_device `. Operations can be +performed on PWM devices to control the period, duty cycle, polarity and +active state of the signal. + +Note that PWM devices are exclusive resources: they can always only be +used by one consumer at a time. + +.. kernel-doc:: include/linux/pwm.h + :internal: + +.. kernel-doc:: drivers/pwm/core.c + :export: -- cgit v1.3.1