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-devfreq-event | 25 ++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-devfreq-event (limited to 'Documentation/ABI/testing/sysfs-class-devfreq-event') diff --git a/Documentation/ABI/testing/sysfs-class-devfreq-event b/Documentation/ABI/testing/sysfs-class-devfreq-event new file mode 100644 index 000000000..dbe48495e --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-devfreq-event @@ -0,0 +1,25 @@ +What: /sys/class/devfreq-event/event/ +Date: January 2017 +Contact: Chanwoo Choi +Description: + Provide a place in sysfs for the devfreq-event objects. + This allows accessing various devfreq-event specific variables. + The name of devfreq-event object denoted as 'event' which + includes the unique number of 'x' for each devfreq-event object. + +What: /sys/class/devfreq-event/event/name +Date: January 2017 +Contact: Chanwoo Choi +Description: + The /sys/class/devfreq-event/event/name attribute contains + the name of the devfreq-event object. This attribute is + read-only. + +What: /sys/class/devfreq-event/event/enable_count +Date: January 2017 +Contact: Chanwoo Choi +Description: + The /sys/class/devfreq-event/event/enable_count attribute + contains the reference count to enable the devfreq-event + object. If the device is enabled, the value of attribute is + greater than zero. -- cgit v1.3.1