korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-11 12:28:41 +08:00
Code Issues Packages Projects Releases Wiki Activity

Add check of order < 0 before calling free_pages()

Browse Source 
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.
 -----BEGIN PGP SIGNATURE-----
 
 iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCYGR30BQccm9zdGVkdEBn
 b29kbWlzLm9yZwAKCRAp5XQQmuv6qnbDAP9yEhTLcDRUi3VLWnEq19Dt4Lsg86Bf
 QRpbWG6Ze9EbZQEAgYAOe1fsNCNEIMXXh/4nlKVpKKH+vviS0ux9Z6uhpQQ=
 =Veyq
 -----END PGP SIGNATURE-----

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()
This commit is contained in:
Linus Torvalds 2021-03-31 10:14:55 -07:00
commit d19cc4bfbf
1 changed files with 6 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
kernel/trace/ftrace.c
View File

@ -3231,7 +3231,8 @@ 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;
@ -6451,7 +6452,8 @@ 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;
@ -6811,7 +6813,8 @@ 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);