Commit 4941a177 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'trace-ringbuffer-v6.18-rc7' of... 

Merge tag 'trace-ringbuffer-v6.18-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull ring-buffer fix from Steven Rostedt:

 - Do not allow mmapped ring buffer to be split

   When the ring buffer VMA is split by a partial munmap or a MAP_FIXED,
   the kernel calls vm_ops->close() on each portion. This causes the
   ring_buffer_unmap() to be called multiple times. This causes
   subsequent calls to return -ENODEV and triggers a warning.

   There's no reason to allow user space to split up memory mapping of
   the ring buffer. Have it return -EINVAL when that happens.

* tag 'trace-ringbuffer-v6.18-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Fix WARN_ON in tracing_buffers_mmap_close for split VMAs
parents 9eb220ed b042fdf1

kernel/trace/trace.c

+10 −0
Original line number Diff line number Diff line
@@ -8781,8 +8781,18 @@ static void tracing_buffers_mmap_close(struct vm_area_struct *vma) 
	put_snapshot_map(iter->tr);

}



static int tracing_buffers_may_split(struct vm_area_struct *vma, unsigned long addr)

{

	/*

	 * Trace buffer mappings require the complete buffer including

	 * the meta page. Partial mappings are not supported.

	 */

	return -EINVAL;

}



static const struct vm_operations_struct tracing_buffers_vmops = {

	.close		= tracing_buffers_mmap_close,

	.may_split      = tracing_buffers_may_split,

};



static int tracing_buffers_mmap(struct file *filp, struct vm_area_struct *vma)