================================================================== BUG: KASAN: use-after-free in check_all_holdout_tasks_trace+0x302/0x420 kernel/rcu/tasks.h:1129 Read of size 1 at addr ffff88801b5458dc by task rcu_tasks_trace/12 CPU: 1 PID: 12 Comm: rcu_tasks_trace Tainted: G W 5.14.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105 print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:233 __kasan_report mm/kasan/report.c:419 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:436 check_all_holdout_tasks_trace+0x302/0x420 kernel/rcu/tasks.h:1129 rcu_tasks_wait_gp+0x57e/0x9c0 kernel/rcu/tasks.h:358 rcu_tasks_kthread+0x31c/0x6a0 kernel/rcu/tasks.h:224 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Allocated by task 23330: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] __kasan_slab_alloc+0x84/0xa0 mm/kasan/common.c:467 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slab.h:512 [inline] slab_alloc_node mm/slub.c:2981 [inline] kmem_cache_alloc_node+0x266/0x3e0 mm/slub.c:3017 alloc_task_struct_node kernel/fork.c:171 [inline] dup_task_struct kernel/fork.c:871 [inline] copy_process+0x5c8/0x7510 kernel/fork.c:1952 kernel_clone+0xe7/0xac0 kernel/fork.c:2510 __do_sys_clone+0xc8/0x110 kernel/fork.c:2627 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Freed by task 12: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free mm/kasan/common.c:328 [inline] __kasan_slab_free+0xfb/0x130 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:229 [inline] slab_free_hook mm/slub.c:1650 [inline] slab_free_freelist_hook+0xdf/0x240 mm/slub.c:1675 slab_free mm/slub.c:3235 [inline] kmem_cache_free+0x8e/0x5a0 mm/slub.c:3251 __put_task_struct+0x26f/0x400 kernel/fork.c:748 trc_wait_for_one_reader kernel/rcu/tasks.h:980 [inline] check_all_holdout_tasks_trace+0x179/0x420 kernel/rcu/tasks.h:1126 rcu_tasks_wait_gp+0x57e/0x9c0 kernel/rcu/tasks.h:358 rcu_tasks_kthread+0x31c/0x6a0 kernel/rcu/tasks.h:224 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Last potentially related work creation: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:348 __call_rcu kernel/rcu/tree.c:3029 [inline] call_rcu+0xb1/0x750 kernel/rcu/tree.c:3109 put_task_struct_rcu_user+0x7f/0xb0 kernel/exit.c:179 release_task+0xcd0/0x17e0 kernel/exit.c:225 wait_task_zombie kernel/exit.c:1107 [inline] wait_consider_task+0x2fa6/0x3b80 kernel/exit.c:1334 do_wait_thread kernel/exit.c:1397 [inline] do_wait+0x6ca/0xce0 kernel/exit.c:1514 kernel_wait4+0x14c/0x260 kernel/exit.c:1677 __do_sys_wait4+0x13f/0x150 kernel/exit.c:1705 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Second to last potentially related work creation: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:348 __call_rcu kernel/rcu/tree.c:3029 [inline] call_rcu+0xb1/0x750 kernel/rcu/tree.c:3109 put_task_struct_rcu_user+0x7f/0xb0 kernel/exit.c:179 context_switch kernel/sched/core.c:4686 [inline] __schedule+0x942/0x26f0 kernel/sched/core.c:5940 schedule_idle+0x57/0x90 kernel/sched/core.c:6047 do_idle+0x303/0x590 kernel/sched/idle.c:334 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:403 start_secondary+0x265/0x340 arch/x86/kernel/smpboot.c:270 secondary_startup_64_no_verify+0xb0/0xbb The buggy address belongs to the object at ffff88801b5454c0 which belongs to the cache task_struct of size 6976 The buggy address is located 1052 bytes inside of 6976-byte region [ffff88801b5454c0, ffff88801b547000) The buggy address belongs to the page: page:ffffea00006d5000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1b540 head:ffffea00006d5000 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888140006280 raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 2, ts 7144375554, free_ts 0 prep_new_page mm/page_alloc.c:2433 [inline] get_page_from_freelist+0xa72/0x2f80 mm/page_alloc.c:4166 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5374 alloc_pages+0x18c/0x2a0 mm/mempolicy.c:2244 alloc_slab_page mm/slub.c:1713 [inline] allocate_slab+0x32b/0x4c0 mm/slub.c:1853 new_slab mm/slub.c:1916 [inline] new_slab_objects mm/slub.c:2662 [inline] ___slab_alloc+0x4ba/0x820 mm/slub.c:2825 __slab_alloc.constprop.0+0xa7/0xf0 mm/slub.c:2865 slab_alloc_node mm/slub.c:2947 [inline] kmem_cache_alloc_node+0x12c/0x3e0 mm/slub.c:3017 alloc_task_struct_node kernel/fork.c:171 [inline] dup_task_struct kernel/fork.c:871 [inline] copy_process+0x5c8/0x7510 kernel/fork.c:1952 kernel_clone+0xe7/0xac0 kernel/fork.c:2510 kernel_thread+0xb5/0xf0 kernel/fork.c:2562 create_kthread kernel/kthread.c:342 [inline] kthreadd+0x4ea/0x750 kernel/kthread.c:685 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 page_owner free stack trace missing Memory state around the buggy address: ffff88801b545780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801b545800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88801b545880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88801b545900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801b545980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================