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

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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
This commit is contained in:
Linus Torvalds
2025-11-26 13:16:22 -08:00
parent 9eb220eddd b042fdf18e
commit 4941a17751
1 changed files with 10 additions and 0 deletions
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10
kernel/trace/trace.c
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@@ -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)