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authorLinus Torvalds <torvalds@linux-foundation.org>2024-10-15 11:18:44 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2024-10-15 11:18:44 -0700
commit2f87d0916ce0d2925cedbc9e8f5d6291ba2ac7b2 (patch)
tree50d5db087ff6e382bdcd775fa1887b0c4d0177a0 /Documentation/litmus-tests/README
parentbdc72765122356796aa72f6e99142cdf24254ce5 (diff)
parent09661f75e75cb6c1d2d8326a70c311d46729235f (diff)
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Merge tag 'trace-ringbuffer-v6.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-traceHEADmaster
Pull ring-buffer fixes from Steven Rostedt: - Fix ref counter of buffers assigned at boot up A tracing instance can be created from the kernel command line. If it maps to memory, it is considered permanent and should not be deleted, or bad things can happen. If it is not mapped to memory, then the user is fine to delete it via rmdir from the instances directory. But the ref counts assumed 0 was free to remove and greater than zero was not. But this was not the case. When an instance is created, it should have the reference of 1, and if it should not be removed, it must be greater than 1. The boot up code set normal instances with a ref count of 0, which could get removed if something accessed it and then released it. And memory mapped instances had a ref count of 1 which meant it could be deleted, and bad things happen. Keep normal instances ref count as 1, and set memory mapped instances ref count to 2. - Protect sub buffer size (order) updates from other modifications When a ring buffer is changing the size of its sub-buffers, no other operations should be performed on the ring buffer. That includes reading it. But the locking only grabbed the buffer->mutex that keeps some operations from touching the ring buffer. It also must hold the cpu_buffer->reader_lock as well when updates happen as other paths use that to do some operations on the ring buffer. * tag 'trace-ringbuffer-v6.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Fix reader locking when changing the sub buffer order ring-buffer: Fix refcount setting of boot mapped buffers
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