EXT4-fs (loop3): re-mounted. Opts: (null) EXT4-fs (loop0): re-mounted. Opts: (null) EXT4-fs (loop2): re-mounted. Opts: (null) EXT4-fs (loop5): re-mounted. Opts: (null) ================================================================== BUG: KASAN: use-after-free in atomic_inc include/asm-generic/atomic-instrumented.h:109 [inline] BUG: KASAN: use-after-free in kthread_stop+0x44/0x4c0 kernel/kthread.c:583 Write of size 4 at addr ffff888091188520 by task syz-executor.3/8459 CPU: 0 PID: 8459 Comm: syz-executor.3 Not tainted 4.19.207-syzkaller #0 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+0x17c/0x226 lib/dump_stack.c:118 print_address_description.cold.6+0x9/0x211 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report mm/kasan/report.c:412 [inline] kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:396 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x13c/0x1b0 mm/kasan/kasan.c:267 kasan_check_write+0x14/0x20 mm/kasan/kasan.c:278 atomic_inc include/asm-generic/atomic-instrumented.h:109 [inline] kthread_stop+0x44/0x4c0 kernel/kthread.c:583 ext4_put_super+0x78a/0xd80 fs/ext4/super.c:1054 generic_shutdown_super+0x12d/0x330 fs/super.c:456 kill_block_super+0x96/0xe0 fs/super.c:1185 deactivate_locked_super+0x77/0xd0 fs/super.c:329 deactivate_super fs/super.c:360 [inline] deactivate_super+0x13f/0x160 fs/super.c:356 cleanup_mnt+0xa3/0x130 fs/namespace.c:1098 __cleanup_mnt+0xd/0x10 fs/namespace.c:1105 task_work_run+0x108/0x180 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x185/0x1e0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x467a37 Code: ff d0 48 89 c7 b8 3c 00 00 00 0f 05 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 b8 a6 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc2ce9f8c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000467a37 RDX: 00007ffc2ce9f99b RSI: 0000000000000002 RDI: 00007ffc2ce9f990 RBP: 00007ffc2ce9f990 R08: 00000000ffffffff R09: 00007ffc2ce9f760 R10: 0000000001fec8e3 R11: 0000000000000246 R12: 00000000004bee70 R13: 00007ffc2cea0a60 R14: 0000000001fec810 R15: 00007ffc2cea0aa0 Allocated by task 2: save_stack mm/kasan/kasan.c:448 [inline] set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc.part.1+0x62/0xf0 mm/kasan/kasan.c:553 kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:538 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490 kmem_cache_alloc_node+0x14f/0x3e0 mm/slab.c:3649 alloc_task_struct_node kernel/fork.c:157 [inline] dup_task_struct kernel/fork.c:807 [inline] copy_process.part.2+0x1513/0x7960 kernel/fork.c:1753 copy_process kernel/fork.c:1719 [inline] _do_fork+0x166/0xc30 kernel/fork.c:2219 kernel_thread+0x24/0x30 kernel/fork.c:2278 create_kthread kernel/kthread.c:282 [inline] kthreadd+0x4e7/0x750 kernel/kthread.c:625 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Freed by task 0: save_stack mm/kasan/kasan.c:448 [inline] set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x13c/0x220 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3503 [inline] kmem_cache_free+0x83/0x290 mm/slab.c:3765 free_task_struct kernel/fork.c:162 [inline] free_task+0xa5/0xd0 kernel/fork.c:421 __put_task_struct+0x24c/0x2d0 kernel/fork.c:694 put_task_struct include/linux/sched/task.h:98 [inline] delayed_put_task_struct+0x145/0x220 kernel/exit.c:181 __rcu_reclaim kernel/rcu/rcu.h:236 [inline] rcu_do_batch kernel/rcu/tree.c:2584 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2897 [inline] __rcu_process_callbacks kernel/rcu/tree.c:2864 [inline] rcu_process_callbacks+0x93a/0x19b0 kernel/rcu/tree.c:2881 __do_softirq+0x25f/0x919 kernel/softirq.c:292 The buggy address belongs to the object at ffff888091188500 which belongs to the cache task_struct of size 6144 The buggy address is located 32 bytes inside of 6144-byte region [ffff888091188500, ffff888091189d00) The buggy address belongs to the page: page:ffffea0002446200 count:1 mapcount:0 mapping:ffff88823b8337c0 index:0x0 compound_mapcount: 0 flags: 0xfff00000008100(slab|head) raw: 00fff00000008100 ffffea0002429288 ffffea00028de888 ffff88823b8337c0 raw: 0000000000000000 ffff888091188500 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888091188400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888091188480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888091188500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888091188580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888091188600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================