================================================================== 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 ffff8801ca3a3908 by task syz-executor4/7512 CPU: 1 PID: 7512 Comm: syz-executor4 Not tainted 4.15.0-rc7-next-20180110+ #93 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:00007f9626e79c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452ac9 RDX: 0000000000000018 RSI: 0000000020fe8fe8 RDI: 0000000000000001 RBP: 0000000000000036 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006ee5b0 R13: 00000000ffffffff R14: 00007f9626e7a6d4 R15: 0000000000000000 Allocated by task 4845: 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] snd_timer_instance_new+0xda/0x610 sound/core/timer.c:108 snd_timer_open+0xa74/0x1b20 sound/core/timer.c:312 snd_seq_timer_open+0x22f/0x710 sound/core/seq/seq_timer.c:287 queue_use+0x8f/0x1e0 sound/core/seq/seq_queue.c:524 snd_seq_queue_alloc+0x337/0x580 sound/core/seq/seq_queue.c:199 snd_seq_ioctl_create_queue+0xad/0x2f0 sound/core/seq/seq_clientmgr.c:1515 snd_seq_kernel_client_ctl+0x122/0x160 sound/core/seq/seq_clientmgr.c:2347 alloc_seq_queue.isra.1+0x11f/0x200 sound/core/seq/oss/seq_oss_init.c:370 snd_seq_oss_open+0x223/0x8b0 sound/core/seq/oss/seq_oss_init.c:228 odev_open+0x6a/0x90 sound/core/seq/oss/seq_oss.c:138 soundcore_open+0x321/0x630 sound/sound_core.c:639 chrdev_open+0x257/0x730 fs/char_dev.c:417 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_openat fs/open.c:1086 [inline] SyS_openat+0x30/0x40 fs/open.c:1080 entry_SYSCALL_64_fastpath+0x29/0xa0 Freed by task 4848: 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 snd_timer_close_locked+0x8ec/0xf90 sound/core/timer.c:399 snd_timer_close+0x2d/0x60 sound/core/timer.c:424 snd_seq_timer_close+0x90/0xd0 sound/core/seq/seq_timer.c:326 queue_delete+0x4e/0xb0 sound/core/seq/seq_queue.c:147 snd_seq_queue_delete+0x3c/0x50 sound/core/seq/seq_queue.c:219 snd_seq_ioctl_delete_queue+0x6a/0x90 sound/core/seq/seq_clientmgr.c:1537 snd_seq_kernel_client_ctl+0x122/0x160 sound/core/seq/seq_clientmgr.c:2347 delete_seq_queue+0xce/0x150 sound/core/seq/oss/seq_oss_init.c:389 snd_seq_oss_release+0xf1/0x120 sound/core/seq/oss/seq_oss_init.c:434 odev_release+0x52/0x70 sound/core/seq/oss/seq_oss.c:153 __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 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x9bb/0x1ad0 kernel/exit.c:869 do_group_exit+0x149/0x400 kernel/exit.c:972 get_signal+0x73f/0x16c0 kernel/signal.c:2337 do_signal+0x90/0x1eb0 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0x258/0x2f0 arch/x86/entry/common.c:161 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 ffff8801ca3a3840 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 200 bytes inside of 256-byte region [ffff8801ca3a3840, ffff8801ca3a3940) The buggy address belongs to the page: page:ffffea000728e8c0 count:1 mapcount:0 mapping:ffff8801ca3a30c0 index:0xffff8801ca3a3340 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffff8801ca3a30c0 ffff8801ca3a3340 000000010000000b raw: ffffea0007216ae0 ffffea0007272ce0 ffff8801dac007c0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801ca3a3800: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff8801ca3a3880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801ca3a3900: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff8801ca3a3980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801ca3a3a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================