From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- Documentation/ABI/testing/debugfs-amd-iommu | 131 ++++++++++++++++++++++++++++ 1 file changed, 131 insertions(+) create mode 100644 Documentation/ABI/testing/debugfs-amd-iommu (limited to 'Documentation/ABI/testing/debugfs-amd-iommu') diff --git a/Documentation/ABI/testing/debugfs-amd-iommu b/Documentation/ABI/testing/debugfs-amd-iommu new file mode 100644 index 000000000..5621a66aa --- /dev/null +++ b/Documentation/ABI/testing/debugfs-amd-iommu @@ -0,0 +1,131 @@ +What: /sys/kernel/debug/iommu/amd/iommu/mmio +Date: January 2025 +Contact: Dheeraj Kumar Srivastava +Description: + This file provides read/write access for user input. Users specify the + MMIO register offset for iommu, and the file outputs the corresponding + MMIO register value of iommu + + Example:: + + $ echo "0x18" > /sys/kernel/debug/iommu/amd/iommu00/mmio + $ cat /sys/kernel/debug/iommu/amd/iommu00/mmio + + Output:: + + Offset:0x18 Value:0x000c22000003f48d + +What: /sys/kernel/debug/iommu/amd/iommu/capability +Date: January 2025 +Contact: Dheeraj Kumar Srivastava +Description: + This file provides read/write access for user input. Users specify the + capability register offset for iommu, and the file outputs the + corresponding capability register value of iommu. + + Example:: + + $ echo "0x10" > /sys/kernel/debug/iommu/amd/iommu00/capability + $ cat /sys/kernel/debug/iommu/amd/iommu00/capability + + Output:: + + Offset:0x10 Value:0x00203040 + +What: /sys/kernel/debug/iommu/amd/iommu/cmdbuf +Date: January 2025 +Contact: Dheeraj Kumar Srivastava +Description: + This file is a read-only output file containing iommu command + buffer entries. + + Examples:: + + $ cat /sys/kernel/debug/iommu/amd/iommu/cmdbuf + + Output:: + + CMD Buffer Head Offset:339 Tail Offset:339 + 0: 00835001 10000001 00003c00 00000000 + 1: 00000000 30000005 fffff003 7fffffff + 2: 00835001 10000001 00003c01 00000000 + 3: 00000000 30000005 fffff003 7fffffff + 4: 00835001 10000001 00003c02 00000000 + 5: 00000000 30000005 fffff003 7fffffff + 6: 00835001 10000001 00003c03 00000000 + 7: 00000000 30000005 fffff003 7fffffff + 8: 00835001 10000001 00003c04 00000000 + 9: 00000000 30000005 fffff003 7fffffff + 10: 00835001 10000001 00003c05 00000000 + 11: 00000000 30000005 fffff003 7fffffff + [...] + +What: /sys/kernel/debug/iommu/amd/devid +Date: January 2025 +Contact: Dheeraj Kumar Srivastava +Description: + This file provides read/write access for user input. Users specify the + device ID, which can be used to dump IOMMU data structures such as the + interrupt remapping table and device table. + + Example: + + 1. + :: + + $ echo 0000:01:00.0 > /sys/kernel/debug/iommu/amd/devid + $ cat /sys/kernel/debug/iommu/amd/devid + + Output:: + + 0000:01:00.0 + + 2. + :: + + $ echo 01:00.0 > /sys/kernel/debug/iommu/amd/devid + $ cat /sys/kernel/debug/iommu/amd/devid + + Output:: + + 0000:01:00.0 + +What: /sys/kernel/debug/iommu/amd/devtbl +Date: January 2025 +Contact: Dheeraj Kumar Srivastava +Description: + This file is a read-only output file containing the device table entry + for the device ID provided in /sys/kernel/debug/iommu/amd/devid. + + Example:: + + $ cat /sys/kernel/debug/iommu/amd/devtbl + + Output:: + + DeviceId QWORD[3] QWORD[2] QWORD[1] QWORD[0] iommu + 0000:01:00.0 0000000000000000 20000001373b8013 0000000000000038 6000000114d7b603 iommu3 + +What: /sys/kernel/debug/iommu/amd/irqtbl +Date: January 2025 +Contact: Dheeraj Kumar Srivastava +Description: + This file is a read-only output file containing valid IRT table entries + for the device ID provided in /sys/kernel/debug/iommu/amd/devid. + + Example:: + + $ cat /sys/kernel/debug/iommu/amd/irqtbl + + Output:: + + DeviceId 0000:01:00.0 + IRT[0000] 0000000000000020 0000000000000241 + IRT[0001] 0000000000000020 0000000000000841 + IRT[0002] 0000000000000020 0000000000002041 + IRT[0003] 0000000000000020 0000000000008041 + IRT[0004] 0000000000000020 0000000000020041 + IRT[0005] 0000000000000020 0000000000080041 + IRT[0006] 0000000000000020 0000000000200041 + IRT[0007] 0000000000000020 0000000000800041 + [...] -- cgit v1.3.1