sock: process `syz-executor0' is using obsolete getsockopt SO_BSDCOMPAT ================================================================== BUG: KASAN: use-after-free in atomic_dec_and_test include/asm-generic/atomic-instrumented.h:259 [inline] BUG: KASAN: use-after-free in put_task_struct include/linux/sched/task.h:95 [inline] BUG: KASAN: use-after-free in _free_event+0x49a/0x1610 kernel/events/core.c:4446 Write of size 4 at addr ffff8801be55c320 by task syz-executor4/7711 CPU: 0 PID: 7711 Comm: syz-executor4 Not tainted 4.19.0-rc5-next-20180928+ #84 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+0x1d3/0x2c4 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 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267 kasan_check_write+0x14/0x20 mm/kasan/kasan.c:278 atomic_dec_and_test include/asm-generic/atomic-instrumented.h:259 [inline] put_task_struct include/linux/sched/task.h:95 [inline] _free_event+0x49a/0x1610 kernel/events/core.c:4446 EXT4-fs warning (device sda1): ext4_resize_fs:1917: can't read last block, resize aborted free_event+0xb4/0x180 kernel/events/core.c:4467 perf_event_release_kernel+0x7d8/0xfa0 kernel/events/core.c:4628 perf_release+0x37/0x50 kernel/events/core.c:4642 __fput+0x3bc/0xa70 fs/file_table.c:279 ____fput+0x15/0x20 fs/file_table.c:312 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x1ad2/0x2610 kernel/exit.c:867 do_group_exit+0x177/0x440 kernel/exit.c:970 get_signal+0x8a8/0x1970 kernel/signal.c:2517 do_signal+0x9c/0x21e0 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x2e5/0x380 arch/x86/entry/common.c:162 prepare_exit_to_usermode+0x342/0x3b0 arch/x86/entry/common.c:197 retint_user+0x8/0x18 RIP: 0033: (null) Code: Bad RIP value. RSP: 002b:0000000020000208 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000457579 RDX: 0000000020000000 RSI: 0000000020000200 RDI: 0000000000000000 RBP: 000000000072bf00 R08: 0000000020000140 R09: 0000000000000000 R10: 0000000020000100 R11: 0000000000000246 R12: 00007fe95af1a6d4 R13: 00000000004bd9fa R14: 00000000004cc448 R15: 00000000ffffffff Allocated by task 7708: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490 kmem_cache_alloc_node+0x144/0x730 mm/slab.c:3644 alloc_task_struct_node kernel/fork.c:158 [inline] dup_task_struct kernel/fork.c:843 [inline] copy_process+0x1ff3/0x8780 kernel/fork.c:1751 _do_fork+0x1cb/0x11c0 kernel/fork.c:2216 __do_sys_clone kernel/fork.c:2323 [inline] __se_sys_clone kernel/fork.c:2317 [inline] __x64_sys_clone+0xbf/0x150 kernel/fork.c:2317 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 7708: save_stack+0x43/0xd0 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:3498 [inline] kmem_cache_free+0x83/0x290 mm/slab.c:3756 free_task_struct kernel/fork.c:163 [inline] free_task+0x16e/0x1f0 kernel/fork.c:457 copy_process+0x1d99/0x8780 kernel/fork.c:2148 _do_fork+0x1cb/0x11c0 kernel/fork.c:2216 __do_sys_clone kernel/fork.c:2323 [inline] __se_sys_clone kernel/fork.c:2317 [inline] __x64_sys_clone+0xbf/0x150 kernel/fork.c:2317 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8801be55c300 which belongs to the cache task_struct(81:syz4) of size 6080 The buggy address is located 32 bytes inside of 6080-byte region [ffff8801be55c300, ffff8801be55dac0) The buggy address belongs to the page: page:ffffea0006f95700 count:1 mapcount:0 mapping:ffff8801bcb3cc40 index:0x0 compound_mapcount: 0 flags: 0x2fffc0000010200(slab|head) raw: 02fffc0000010200 ffffea0006184d88 ffffea000614b288 ffff8801bcb3cc40 raw: 0000000000000000 ffff8801be55c300 0000000100000001 ffff8801c79daac0 page dumped because: kasan: bad access detected page->mem_cgroup:ffff8801c79daac0 Memory state around the buggy address: ffff8801be55c200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801be55c280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8801be55c300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801be55c380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801be55c400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================