================================================================== BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:188 [inline] BUG: KASAN: use-after-free in bpf_fd_array_map_lookup_elem+0x440/0x4c0 kernel/bpf/arraymap.c:374 Read of size 8 at addr ffff8801d4028d88 by task syz-executor7/8625 CPU: 0 PID: 8625 Comm: syz-executor7 Not tainted 4.15.0-rc7-next-20180111+ #94 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report+0x23b/0x360 mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 __read_once_size include/linux/compiler.h:188 [inline] bpf_fd_array_map_lookup_elem+0x440/0x4c0 kernel/bpf/arraymap.c:374 map_lookup_elem+0x6b5/0xbd0 kernel/bpf/syscall.c:577 SYSC_bpf kernel/bpf/syscall.c:1808 [inline] SyS_bpf+0x922/0x4400 kernel/bpf/syscall.c:1782 entry_SYSCALL_64_fastpath+0x29/0xa0 RIP: 0033:0x452ac9 RSP: 002b:00007f1f2d129c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f1f2d12a700 RCX: 0000000000452ac9 RDX: 0000000000000018 RSI: 0000000020fe8fe8 RDI: 0000000000000001 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000 R13: 0000000000a2f7ef R14: 00007f1f2d12a9c0 R15: 0000000000000000 Allocated by task 1782: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:552 kmem_cache_alloc_trace+0x136/0x750 mm/slab.c:3607 kmalloc include/linux/slab.h:515 [inline] kzalloc include/linux/slab.h:704 [inline] seq_open+0x83/0x1f0 fs/seq_file.c:54 kernfs_fop_open+0x684/0xeb0 fs/kernfs/file.c:704 do_dentry_open+0x667/0xd40 fs/open.c:752 vfs_open+0x107/0x220 fs/open.c:866 do_last fs/namei.c:3397 [inline] path_openat+0x1151/0x3530 fs/namei.c:3537 do_filp_open+0x25b/0x3b0 fs/namei.c:3572 do_sys_open+0x502/0x6d0 fs/open.c:1059 SYSC_open fs/open.c:1077 [inline] SyS_open+0x2d/0x40 fs/open.c:1072 entry_SYSCALL_64_fastpath+0x29/0xa0 Freed by task 1782: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527 __cache_free mm/slab.c:3485 [inline] kfree+0xd9/0x260 mm/slab.c:3800 seq_release+0x59/0x70 fs/seq_file.c:366 kernfs_fop_release+0x10b/0x180 fs/kernfs/file.c:781 __fput+0x327/0x7e0 fs/file_table.c:209 ____fput+0x15/0x20 fs/file_table.c:243 task_work_run+0x199/0x270 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x275/0x2f0 arch/x86/entry/common.c:165 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264 entry_SYSCALL_64_fastpath+0x9e/0xa0 The buggy address belongs to the object at ffff8801d4028cc0 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 200 bytes inside of 256-byte region [ffff8801d4028cc0, ffff8801d4028dc0) The buggy address belongs to the page: page:ffffea0007500a00 count:1 mapcount:0 mapping:ffff8801d4028040 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffff8801d4028040 0000000000000000 000000010000000c raw: ffffea0007500720 ffffea000750a7a0 ffff8801dac007c0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d4028c80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff8801d4028d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801d4028d80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff8801d4028e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801d4028e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================