audit: type=1400 audit(1569100350.017:36): avc: denied { map } for pid=7470 comm="syz-executor130" path="/root/syz-executor130702833" dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 ================================================================== BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:193 [inline] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 kernel/exit.c:1345 Read of size 4 at addr ffff88808ffda72c by task sshd/7468 CPU: 1 PID: 7468 Comm: sshd Not tainted 4.19.75 #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+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d 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+0x8c/0x2ba mm/kasan/report.c:396 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432 __read_once_size include/linux/compiler.h:193 [inline] wait_consider_task+0x1b51/0x3910 kernel/exit.c:1345 do_wait_thread kernel/exit.c:1454 [inline] do_wait+0x439/0x9d0 kernel/exit.c:1525 kernel_wait4+0x171/0x290 kernel/exit.c:1668 __do_sys_wait4+0x147/0x160 kernel/exit.c:1680 __se_sys_wait4 kernel/exit.c:1676 [inline] __x64_sys_wait4+0x97/0xf0 kernel/exit.c:1676 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7ff283ffba3e Code: 90 90 90 90 90 90 90 90 90 90 90 90 48 83 ec 28 8b 05 c2 eb 2d 00 85 c0 75 1d 45 31 d2 48 63 d2 48 63 ff b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 55 48 83 c4 28 c3 89 54 24 08 48 89 74 24 10 RSP: 002b:00007ffeafe45cd0 EFLAGS: 00000246 ORIG_RAX: 000000000000003d RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff283ffba3e RDX: 0000000000000001 RSI: 00007ffeafe45d0c RDI: ffffffffffffffff RBP: 000055b207fc3c88 R08: 00007ffeafe45dd0 R09: 0101010101010101 R10: 0000000000000000 R11: 0000000000000246 R12: 000055b20999cc00 R13: 000055b207fc1fb4 R14: 0000000000000028 R15: 000055b207fc3ca0 Allocated by task 7468: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc mm/kasan/kasan.c:553 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:531 kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:490 kmem_cache_alloc_node+0x144/0x710 mm/slab.c:3649 alloc_task_struct_node kernel/fork.c:157 [inline] dup_task_struct kernel/fork.c:802 [inline] copy_process.part.0+0x1ce0/0x7a30 kernel/fork.c:1732 copy_process kernel/fork.c:1689 [inline] _do_fork+0x257/0xfd0 kernel/fork.c:2202 __do_sys_clone kernel/fork.c:2309 [inline] __se_sys_clone kernel/fork.c:2303 [inline] __x64_sys_clone+0xbf/0x150 kernel/fork.c:2303 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 0: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 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+0x86/0x260 mm/slab.c:3765 free_task_struct kernel/fork.c:162 [inline] free_task+0xdd/0x120 kernel/fork.c:416 __put_task_struct+0x20f/0x4c0 kernel/fork.c:689 put_task_struct include/linux/sched/task.h:96 [inline] finish_task_switch+0x52b/0x780 kernel/sched/core.c:2710 context_switch kernel/sched/core.c:2829 [inline] __schedule+0x86e/0x1dc0 kernel/sched/core.c:3474 schedule_idle+0x58/0x80 kernel/sched/core.c:3545 do_idle+0x192/0x560 kernel/sched/idle.c:286 cpu_startup_entry+0xc8/0xe0 kernel/sched/idle.c:368 rest_init+0x219/0x222 init/main.c:442 start_kernel+0x88c/0x8c5 init/main.c:738 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:472 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:453 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 The buggy address belongs to the object at ffff88808ffda2c0 which belongs to the cache task_struct of size 6080 The buggy address is located 1132 bytes inside of 6080-byte region [ffff88808ffda2c0, ffff88808ffdba80) The buggy address belongs to the page: page:ffffea00023ff680 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000008100(slab|head) raw: 01fffc0000008100 ffffea00027c8a88 ffffea00029e9988 ffff88812c26d800 raw: 0000000000000000 ffff88808ffda2c0 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808ffda600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808ffda680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88808ffda700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88808ffda780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808ffda800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================