The function addresses that are traced by ftrace are stored in pages,
and the size is held in a variable. If there's some error in creating
them, the allocate ones will be freed. In this case, it is possible that
the order of pages to be freed may end up being negative due to a size of
zero passed to get_count_order(), and then that negative number will cause
free_pages() to free a very large section. Make sure that does not happen.
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Merge tag 'trace-v5.12-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull ftrace fix from Steven Rostedt:
"Add check of order < 0 before calling free_pages()
The function addresses that are traced by ftrace are stored in pages,
and the size is held in a variable. If there's some error in creating
them, the allocate ones will be freed. In this case, it is possible
that the order of pages to be freed may end up being negative due to a
size of zero passed to get_count_order(), and then that negative
number will cause free_pages() to free a very large section.
Make sure that does not happen"
* tag 'trace-v5.12-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace: Check if pages were allocated before calling free_pages()
d19cc4bfbf