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 --- .../ABI/testing/sysfs-class-led-trigger-pattern | 50 ++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-led-trigger-pattern (limited to 'Documentation/ABI/testing/sysfs-class-led-trigger-pattern') diff --git a/Documentation/ABI/testing/sysfs-class-led-trigger-pattern b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern new file mode 100644 index 000000000..22f28f2e9 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern @@ -0,0 +1,50 @@ +What: /sys/class/leds//pattern +Date: September 2018 +KernelVersion: 4.20 +Description: + Specify a software pattern for the LED, that supports altering + the brightness for the specified duration with one software + timer. It can do gradual dimming and step change of brightness. + + The pattern is given by a series of tuples, of brightness and + duration (ms). + + The exact format is described in: + Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt + +What: /sys/class/leds//hr_pattern +Date: April 2024 +Description: + Specify a software pattern for the LED, that supports altering + the brightness for the specified duration with one software + timer. It can do gradual dimming and step change of brightness. + + Unlike the /sys/class/leds//pattern, this attribute runs + a pattern on high-resolution timer (hrtimer). + +What: /sys/class/leds//hw_pattern +Date: September 2018 +KernelVersion: 4.20 +Description: + Specify a hardware pattern for the LED, for LED hardware that + supports autonomously controlling brightness over time, according + to some preprogrammed hardware patterns. It deactivates any active + software pattern. + + Since different LED hardware can have different semantics of + hardware patterns, each driver is expected to provide its own + description for the hardware patterns in their documentation + file at Documentation/leds/. + +What: /sys/class/leds//repeat +Date: September 2018 +KernelVersion: 4.20 +Description: + Specify a pattern repeat number. -1 means repeat indefinitely, + other negative numbers and number 0 are invalid. + + This file will always return the originally written repeat + number. + + It should be noticed that some leds, like EL15203000 may + only support indefinitely patterns, so they always store -1. -- cgit v1.3.1