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/debugfs-tpmi | 40 ++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 Documentation/ABI/testing/debugfs-tpmi (limited to 'Documentation/ABI/testing/debugfs-tpmi') diff --git a/Documentation/ABI/testing/debugfs-tpmi b/Documentation/ABI/testing/debugfs-tpmi new file mode 100644 index 000000000..c493a1403 --- /dev/null +++ b/Documentation/ABI/testing/debugfs-tpmi @@ -0,0 +1,40 @@ +What: /sys/kernel/debug/tpmi-/pfs_dump +Date: November 2023 +KernelVersion: 6.6 +Contact: srinivas.pandruvada@linux.intel.com +Description: +The PFS (PM Feature Structure) table, shows details of each power +management feature. This includes: +tpmi_id, number of entries, entry size, offset, vsec offset, lock status +and disabled status. +Users: Debugging, any user space test suite + +What: /sys/kernel/debug/tpmi-/tpmi-id-/mem_dump +Date: November 2023 +KernelVersion: 6.6 +Contact: srinivas.pandruvada@linux.intel.com +Description: +Shows the memory dump of the MMIO region for a TPMI ID. +Users: Debugging, any user space test suite + +What: /sys/kernel/debug/tpmi-/tpmi-id-/mem_write +Date: November 2023 +KernelVersion: 6.6 +Contact: srinivas.pandruvada@linux.intel.com +Description: +Allows to write at any offset. It doesn't check for Read/Write access +as hardware will not allow to write at read-only memory. This write is +at offset multiples of 4. The format is instance,offset,contents. +Example: +echo 0,0x20,0xff > mem_write +echo 1,64,64 > mem_write +Users: Debugging, any user space test suite + +What: /sys/kernel/debug/tpmi-/plr/domain/status +Date: Aug 2024 +KernelVersion: 6.11 +Contact: Tero Kristo +Description: +Shows the currently active Performance Limit Reasons for die level and the +individual CPUs under the die. The contents of this file are sticky, and +clearing all the statuses can be done by writing "0\n" to this file. -- cgit v1.3.1