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-scmi | 70 ++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) create mode 100644 Documentation/ABI/testing/debugfs-scmi (limited to 'Documentation/ABI/testing/debugfs-scmi') diff --git a/Documentation/ABI/testing/debugfs-scmi b/Documentation/ABI/testing/debugfs-scmi new file mode 100644 index 000000000..ee7179ab2 --- /dev/null +++ b/Documentation/ABI/testing/debugfs-scmi @@ -0,0 +1,70 @@ +What: /sys/kernel/debug/scmi//instance_name +Date: March 2023 +KernelVersion: 6.3 +Contact: cristian.marussi@arm.com +Description: The name of the underlying SCMI instance described by + all the debugfs accessors rooted at /sys/kernel/debug/scmi/, + expressed as the full name of the top DT SCMI node under which + this SCMI instance is rooted. +Users: Debugging, any userspace test suite + +What: /sys/kernel/debug/scmi//atomic_threshold_us +Date: March 2023 +KernelVersion: 6.3 +Contact: cristian.marussi@arm.com +Description: An optional time value, expressed in microseconds, representing, + on this SCMI instance , the threshold above which any SCMI + command, advertised to have an higher-than-threshold execution + latency, should not be considered for atomic mode of operation, + even if requested. +Users: Debugging, any userspace test suite + +What: /sys/kernel/debug/scmi//transport/type +Date: March 2023 +KernelVersion: 6.3 +Contact: cristian.marussi@arm.com +Description: A string representing the type of transport configured for this + SCMI instance . +Users: Debugging, any userspace test suite + +What: /sys/kernel/debug/scmi//transport/is_atomic +Date: March 2023 +KernelVersion: 6.3 +Contact: cristian.marussi@arm.com +Description: A boolean stating if the transport configured on the underlying + SCMI instance is capable of atomic mode of operation. +Users: Debugging, any userspace test suite + +What: /sys/kernel/debug/scmi//transport/max_rx_timeout_ms +Date: March 2023 +KernelVersion: 6.3 +Contact: cristian.marussi@arm.com +Description: Timeout in milliseconds allowed for SCMI synchronous replies + for the currently configured SCMI transport for instance . +Users: Debugging, any userspace test suite + +What: /sys/kernel/debug/scmi//transport/max_msg_size +Date: March 2023 +KernelVersion: 6.3 +Contact: cristian.marussi@arm.com +Description: Max message size of allowed SCMI messages for the currently + configured SCMI transport for instance . +Users: Debugging, any userspace test suite + +What: /sys/kernel/debug/scmi//transport/tx_max_msg +Date: March 2023 +KernelVersion: 6.3 +Contact: cristian.marussi@arm.com +Description: Max number of concurrently allowed in-flight SCMI messages for + the currently configured SCMI transport for instance on the + TX channels. +Users: Debugging, any userspace test suite + +What: /sys/kernel/debug/scmi//transport/rx_max_msg +Date: March 2023 +KernelVersion: 6.3 +Contact: cristian.marussi@arm.com +Description: Max number of concurrently allowed in-flight SCMI messages for + the currently configured SCMI transport for instance on the + RX channels. +Users: Debugging, any userspace test suite -- cgit v1.3.1