On 2018/10/21 16:10, syzbot wrote: > BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:188 > [inline] > BUG: KASAN: use-after-free in task_is_descendant.part.2+0x610/0x670 > security/yama/yama_lsm.c:295 > Read of size 8 at addr ffff8801c4666b20 by task syz-executor3/12722 > > CPU: 1 PID: 12722 Comm: syz-executor3 Not tainted 4.19.0-rc8+ #70 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113 > print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256 > kasan_report_error mm/kasan/report.c:354 [inline] > kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412 > __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 > __read_once_size include/linux/compiler.h:188 [inline] > task_is_descendant.part.2+0x610/0x670 security/yama/yama_lsm.c:295
Do we need to hold write_lock_irq(&tasklist_lock); rather than rcu_read_lock(); when accessing "struct task_struct"->real_parent ?
