audit: type=1400 audit(1569066514.675:35): avc: denied { map } for pid=7832 comm="bash" path="/bin/bash" dev="sda1" ino=1457 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1569066521.135:36): avc: denied { map } for pid=7844 comm="syz-executor254" path="/root/syz-executor254428454" dev="sda1" ino=16484 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 thread_group_leader include/linux/sched/signal.h:627 [inline] BUG: KASAN: use-after-free in wait_consider_task+0x2f44/0x3910 kernel/exit.c:1384 Read of size 4 at addr ffff88808b22c634 by task sshd/7842 CPU: 0 PID: 7842 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 thread_group_leader include/linux/sched/signal.h:627 [inline] wait_consider_task+0x2f44/0x3910 kernel/exit.c:1384 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: 0033:0x7f3eba144a3e 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:00007ffc35641700 EFLAGS: 00000246 ORIG_RAX: 000000000000003d RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3eba144a3e RDX: 0000000000000001 RSI: 00007ffc3564173c RDI: ffffffffffffffff RBP: 00005621ba900c88 R08: 00007ffc35641800 R09: 0101010101010101 R10: 0000000000000000 R11: 0000000000000246 R12: 00005621bbd22c00 R13: 00005621ba8fefb4 R14: 0000000000000028 R15: 00005621ba900ca0 Allocated by task 7842: 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 start_secondary+0x3e8/0x5b0 arch/x86/kernel/smpboot.c:271 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 The buggy address belongs to the object at ffff88808b22c1c0 which belongs to the cache task_struct of size 6080 The buggy address is located 1140 bytes inside of 6080-byte region [ffff88808b22c1c0, ffff88808b22d980) The buggy address belongs to the page: page:ffffea00022c8b00 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000008100(slab|head) raw: 01fffc0000008100 ffffea00023dee88 ffffea0002a14888 ffff88812c26d800 raw: 0000000000000000 ffff88808b22c1c0 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808b22c500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808b22c580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88808b22c600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88808b22c680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808b22c700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================