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/ABI/testing/sysfs-class-lcd | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-lcd (limited to 'Documentation/ABI/testing/sysfs-class-lcd') diff --git a/Documentation/ABI/testing/sysfs-class-lcd b/Documentation/ABI/testing/sysfs-class-lcd new file mode 100644 index 000000000..35906bf7a --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-lcd @@ -0,0 +1,23 @@ +What: /sys/class/lcd//lcd_power +Date: April 2005 +KernelVersion: 2.6.12 +Contact: Richard Purdie +Description: + Control LCD power, values are FB_BLANK_* from fb.h + - FB_BLANK_UNBLANK (0) : power on. + - FB_BLANK_POWERDOWN (4) : power off + +What: /sys/class/lcd//contrast +Date: April 2005 +KernelVersion: 2.6.12 +Contact: Richard Purdie +Description: + Current contrast of this LCD device. Value is between 0 and + /sys/class/lcd//max_contrast. + +What: /sys/class/lcd//max_contrast +Date: April 2005 +KernelVersion: 2.6.12 +Contact: Richard Purdie +Description: + Maximum contrast for this LCD device. -- cgit v1.3.1