================================================================== BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] BUG: KASAN: use-after-free in refcount_sub_and_test_checked+0x87/0x200 lib/refcount.c:182 Read of size 4 at addr ffff888064c4e1a0 by task syz-executor.3/8053 CPU: 1 PID: 8053 Comm: syz-executor.3 Not tainted 5.0.0-rc6-next-20190215 #36 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:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 check_memory_region_inline mm/kasan/generic.c:185 [inline] check_memory_region+0x123/0x190 mm/kasan/generic.c:191 kasan_check_read+0x11/0x20 mm/kasan/common.c:102 atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] refcount_sub_and_test_checked+0x87/0x200 lib/refcount.c:182 refcount_dec_and_test_checked+0x1b/0x20 lib/refcount.c:220 put_task_struct include/linux/sched/task.h:97 [inline] _free_event+0x3d7/0x13b0 kernel/events/core.c:4457 free_event+0x5f/0xd0 kernel/events/core.c:4478 perf_event_release_kernel+0x5b2/0xbe0 kernel/events/core.c:4639 perf_release+0x37/0x50 kernel/events/core.c:4653 __fput+0x2e5/0x8d0 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x14a/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x411d31 Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 94 19 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007ffd863df200 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000411d31 RDX: 0000000000000000 RSI: 00000000000006fd RDI: 0000000000000004 RBP: 0000000000000000 R08: 00000000863ec6fd R09: 00000000863ec701 R10: 00007ffd863df130 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000002146 R15: 0000000000000003 Allocated by task 8070: save_stack+0x45/0xd0 mm/kasan/common.c:75 set_track mm/kasan/common.c:87 [inline] __kasan_kmalloc mm/kasan/common.c:497 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:470 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:505 kmem_cache_alloc_node+0x144/0x710 mm/slab.c:3641 alloc_task_struct_node kernel/fork.c:157 [inline] dup_task_struct kernel/fork.c:844 [inline] copy_process.part.0+0x1d35/0x79e0 kernel/fork.c:1753 copy_process kernel/fork.c:1710 [inline] _do_fork+0x257/0xfd0 kernel/fork.c:2227 __do_sys_clone kernel/fork.c:2334 [inline] __se_sys_clone kernel/fork.c:2328 [inline] __x64_sys_clone+0xbf/0x150 kernel/fork.c:2328 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 8070: save_stack+0x45/0xd0 mm/kasan/common.c:75 set_track mm/kasan/common.c:87 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:459 kasan_slab_free+0xe/0x10 mm/kasan/common.c:467 __cache_free mm/slab.c:3491 [inline] kmem_cache_free+0x86/0x260 mm/slab.c:3759 free_task_struct kernel/fork.c:162 [inline] free_task+0xdd/0x120 kernel/fork.c:457 copy_process.part.0+0x1a67/0x79e0 kernel/fork.c:2159 copy_process kernel/fork.c:1710 [inline] _do_fork+0x257/0xfd0 kernel/fork.c:2227 __do_sys_clone kernel/fork.c:2334 [inline] __se_sys_clone kernel/fork.c:2328 [inline] __x64_sys_clone+0xbf/0x150 kernel/fork.c:2328 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff888064c4e180 which belongs to the cache task_struct(65:syz3) of size 6080 The buggy address is located 32 bytes inside of 6080-byte region [ffff888064c4e180, ffff888064c4f940) The buggy address belongs to the page: page:ffffea0001931380 count:1 mapcount:0 mapping:ffff88802fe80b00 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea0000aa1f88 ffffea0000fcd188 ffff88802fe80b00 raw: 0000000000000000 ffff888064c4e180 0000000100000001 ffff88805353aa00 page dumped because: kasan: bad access detected page->mem_cgroup:ffff88805353aa00 Memory state around the buggy address: ffff888064c4e080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888064c4e100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888064c4e180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888064c4e200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888064c4e280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================