From 27600805e62f800bacf990354632eae4e487d34c Mon Sep 17 00:00:00 2001 From: Yazen Ghannam Date: Thu, 3 Sep 2026 10:43:25 -0500 Subject: x86/amd_node: Fix PCI device reference counting in amd_smn_init() The local "root" pointer is a temporary variable used during the device search. Therefore, refcount related to the search iterators should be cleaned up after the search is complete. Use the __free() cleanup macro to ensure the refcount is decremented when the temporary pointer goes out of scope. Additionally, increment the refcount when caching a root pointer. This ensures the in-use refcount is separate from the temporary search refcounting. Finally, drop the redundant "root = NULL" before the second search loop. The pci_get_class() iterator always decrements the refcount of its "from" argument, so the first loop can only fall through with "root" already NULL. Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching") Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com Reported-by: Sashiko Assisted-by: LLM Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Mario Limonciello (AMD) Cc: Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com --- Documentation/ABI/testing/sysfs-uevent | 51 ++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-uevent (limited to 'Documentation/ABI/testing/sysfs-uevent') diff --git a/Documentation/ABI/testing/sysfs-uevent b/Documentation/ABI/testing/sysfs-uevent new file mode 100644 index 000000000..c15e18c47 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-uevent @@ -0,0 +1,51 @@ +What: /sys/.../uevent +Date: May 2017 +KernelVersion: 4.13 +Contact: Linux kernel mailing list +Description: + Enable passing additional variables for synthetic uevents that + are generated by writing /sys/.../uevent file. + + Recognized extended format is:: + + ACTION [UUID [KEY=VALUE ...]] + + The ACTION is compulsory - it is the name of the uevent + action (``add``, ``change``, ``remove``). There is no change + compared to previous functionality here. The rest of the + extended format is optional. + + You need to pass UUID first before any KEY=VALUE pairs. + The UUID must be in ``xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx`` + format where 'x' is a hex digit. The UUID is considered to be + a transaction identifier so it's possible to use the same UUID + value for one or more synthetic uevents in which case we + logically group these uevents together for any userspace + listeners. The UUID value appears in uevent as + ``SYNTH_UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx`` environment + variable. + + If UUID is not passed in, the generated synthetic uevent gains + ``SYNTH_UUID=0`` environment variable automatically. + + The KEY=VALUE pairs can contain alphanumeric characters only. + + It's possible to define zero or more pairs - each pair is then + delimited by a space character ' '. Each pair appears in + synthetic uevent as ``SYNTH_ARG_KEY=VALUE``. That means the KEY + name gains ``SYNTH_ARG_`` prefix to avoid possible collisions + with existing variables. + + Example of valid sequence written to the uevent file:: + + add fe4d7c9d-b8c6-4a70-9ef1-3d8a58d18eed A=1 B=abc + + This generates synthetic uevent including these variables:: + + ACTION=add + SYNTH_ARG_A=1 + SYNTH_ARG_B=abc + SYNTH_UUID=fe4d7c9d-b8c6-4a70-9ef1-3d8a58d18eed + +Users: + udev, userspace tools generating synthetic uevents -- cgit v1.3.1