Commit 034dd340b08b for kernel

commit 034dd340b08be1f2f0477ad16131d609f9dbd53c
Merge: 08dbfad3f504 5eab74874d11
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sun Aug 30 09:22:00 2026 -0700

    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