From: Steven Rostedt (VMware) rostedt@goodmis.org
[ Upstream commit 59300b36f85f254260c81d9dd09195fa49eb0f98 ]
It is possible that on error pg->size can be zero when getting its order, which would return a -1 value. It is dangerous to pass in an order of -1 to free_pages(). Check if order is greater than or equal to zero before calling free_pages().
Link: https://lore.kernel.org/lkml/20210330093916.432697c7@gandalf.local.home/
Reported-by: Abaci Robot abaci@linux.alibaba.com Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Stable-dep-of: 26efd79c4624 ("ftrace: Fix possible warning on checking all pages used in ftrace_process_locs()") Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/trace/ftrace.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 97d615988ea35..5f5a766bf73bb 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3079,7 +3079,8 @@ ftrace_allocate_pages(unsigned long num_to_init) pg = start_pg; while (pg) { order = get_count_order(pg->size / ENTRIES_PER_PAGE); - free_pages((unsigned long)pg->records, order); + if (order >= 0) + free_pages((unsigned long)pg->records, order); start_pg = pg->next; kfree(pg); pg = start_pg; @@ -5877,7 +5878,8 @@ void ftrace_release_mod(struct module *mod) clear_mod_from_hashes(pg);
order = get_count_order(pg->size / ENTRIES_PER_PAGE); - free_pages((unsigned long)pg->records, order); + if (order >= 0) + free_pages((unsigned long)pg->records, order); tmp_page = pg->next; kfree(pg); ftrace_number_of_pages -= 1 << order; @@ -6222,7 +6224,8 @@ void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr) if (!pg->index) { *last_pg = pg->next; order = get_count_order(pg->size / ENTRIES_PER_PAGE); - free_pages((unsigned long)pg->records, order); + if (order >= 0) + free_pages((unsigned long)pg->records, order); ftrace_number_of_pages -= 1 << order; ftrace_number_of_groups--; kfree(pg);