On 2021-12-01 14:34, Jan Kara wrote:

BFQ started crashing with 5.15-based kernels like:

BUG: KASAN: use-after-free in rb_erase (lib/rbtree.c:262 lib/rbtr
Read of size 8 at addr ffff888008193098 by task bash/1472

[snip]

This does not compile when CONFIG_BFQ_GROUP_IOSCHED is disabled.
I know the patch is meant for the case where it is enabled, but still..

block/bfq-iosched.c: In function 'bfq_init_bfqq':
block/bfq-iosched.c:5362:51: error: 'struct bfq_group' has no member named 'children'
  5362 |         hlist_add_head(&bfqq->children_node, &bfqg->children);
       |                                                   ^~
make[1]: *** [scripts/Makefile.build:277: block/bfq-iosched.o] Error 1

Probably just needs a few more ifdefs :)

cheers
Holger