================================================================== BUG: KASAN: use-after-free in snd_rawmidi_poll+0x559/0x680 sound/core/rawmidi.c:1655 Read of size 8 at addr ffff888026b24ec8 by task syz-executor.1/5291 CPU: 0 PID: 5291 Comm: syz-executor.1 Not tainted 6.2.0-rc3-next-20230112-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:306 [inline] print_report+0x15e/0x45d mm/kasan/report.c:417 kasan_report+0xc0/0xf0 mm/kasan/report.c:517 snd_rawmidi_poll+0x559/0x680 sound/core/rawmidi.c:1655 vfs_poll include/linux/poll.h:88 [inline] io_poll_check_events io_uring/poll.c:279 [inline] io_poll_task_func+0x3a6/0x1220 io_uring/poll.c:327 handle_tw_list+0xa8/0x460 io_uring/io_uring.c:1169 tctx_task_work+0x12e/0x530 io_uring/io_uring.c:1224 task_work_run+0x16f/0x270 kernel/task_work.c:179 get_signal+0x1c7/0x24f0 kernel/signal.c:2635 arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306 exit_to_user_mode_loop kernel/entry/common.c:168 [inline] exit_to_user_mode_prepare+0x11f/0x240 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:297 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fd082c8c0c9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fd08392c168 EFLAGS: 00000246 ORIG_RAX: 0000000000000048 RAX: fffffffffffffe00 RBX: 00007fd082dabf80 RCX: 00007fd082c8c0c9 RDX: 0000000020000180 RSI: 0000000000000026 RDI: 0000000000000006 RBP: 00007fd082ce7ae9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe4aec9b2f R14: 00007fd08392c300 R15: 0000000000022000 Allocated by task 5291: kasan_save_stack+0x22/0x40 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:371 [inline] ____kasan_kmalloc mm/kasan/common.c:330 [inline] __kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:380 kmalloc include/linux/slab.h:580 [inline] snd_rawmidi_open+0x39a/0xb70 sound/core/rawmidi.c:482 snd_open+0x223/0x460 sound/core/sound.c:169 chrdev_open+0x26a/0x770 fs/char_dev.c:414 do_dentry_open+0x6cc/0x13f0 fs/open.c:883 do_open fs/namei.c:3558 [inline] path_openat+0x1bc1/0x2b40 fs/namei.c:3715 do_filp_open+0x1ba/0x410 fs/namei.c:3742 do_sys_openat2+0x16d/0x4c0 fs/open.c:1311 do_sys_open fs/open.c:1327 [inline] __do_sys_openat fs/open.c:1343 [inline] __se_sys_openat fs/open.c:1338 [inline] __x64_sys_openat+0x143/0x1f0 fs/open.c:1338 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 5291: kasan_save_stack+0x22/0x40 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 kasan_save_free_info+0x2e/0x40 mm/kasan/generic.c:518 ____kasan_slab_free mm/kasan/common.c:236 [inline] ____kasan_slab_free+0x160/0x1c0 mm/kasan/common.c:200 kasan_slab_free include/linux/kasan.h:162 [inline] slab_free_hook mm/slub.c:1781 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1807 slab_free mm/slub.c:3787 [inline] __kmem_cache_free+0xaf/0x2d0 mm/slub.c:3800 snd_rawmidi_release+0x6a/0xf0 sound/core/rawmidi.c:619 __fput+0x27c/0xa90 fs/file_table.c:321 task_work_run+0x16f/0x270 kernel/task_work.c:179 get_signal+0x1c7/0x24f0 kernel/signal.c:2635 arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306 exit_to_user_mode_loop kernel/entry/common.c:168 [inline] exit_to_user_mode_prepare+0x11f/0x240 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:297 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd The buggy address belongs to the object at ffff888026b24ec0 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 8 bytes inside of 32-byte region [ffff888026b24ec0, ffff888026b24ee0) The buggy address belongs to the physical page: page:ffffea00009ac900 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x26b24 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffff888012441500 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000400040 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 5125, tgid 5125 (syz-executor.4), ts 333939277140, free_ts 331662368039 prep_new_page mm/page_alloc.c:2549 [inline] get_page_from_freelist+0x11bb/0x2d50 mm/page_alloc.c:4324 __alloc_pages+0x1cb/0x5c0 mm/page_alloc.c:5590 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2281 alloc_slab_page mm/slub.c:1851 [inline] allocate_slab+0x25f/0x350 mm/slub.c:1998 new_slab mm/slub.c:2051 [inline] ___slab_alloc+0xa91/0x1400 mm/slub.c:3193 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3292 __slab_alloc_node mm/slub.c:3345 [inline] slab_alloc_node mm/slub.c:3442 [inline] __kmem_cache_alloc_node+0x136/0x330 mm/slub.c:3491 __do_kmalloc_node mm/slab_common.c:966 [inline] __kmalloc_node_track_caller+0x4b/0xc0 mm/slab_common.c:987 kstrdup+0x3f/0x70 mm/util.c:61 kstrdup_const+0x57/0x80 mm/util.c:84 __kernfs_new_node+0x9d/0x8b0 fs/kernfs/dir.c:610 kernfs_new_node+0x97/0x120 fs/kernfs/dir.c:676 __kernfs_create_file+0x55/0x350 fs/kernfs/file.c:1047 cgroup_add_file kernel/cgroup/cgroup.c:4185 [inline] cgroup_addrm_files+0x3d6/0x9c0 kernel/cgroup/cgroup.c:4245 css_populate_dir+0x19e/0x560 kernel/cgroup/cgroup.c:1767 cgroup_apply_control_enable+0x3fd/0xc00 kernel/cgroup/cgroup.c:3247 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1451 [inline] free_pcp_prepare+0x4d0/0x910 mm/page_alloc.c:1501 free_unref_page_prepare mm/page_alloc.c:3387 [inline] free_unref_page+0x1d/0x490 mm/page_alloc.c:3482 __unfreeze_partials+0x17c/0x1a0 mm/slub.c:2637 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x192/0x220 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x63/0x90 mm/kasan/common.c:302 kasan_slab_alloc include/linux/kasan.h:186 [inline] slab_post_alloc_hook mm/slab.h:769 [inline] slab_alloc_node mm/slub.c:3452 [inline] kmem_cache_alloc_node+0x183/0x350 mm/slub.c:3497 __alloc_skb+0x216/0x310 net/core/skbuff.c:550 alloc_skb include/linux/skbuff.h:1270 [inline] alloc_skb_with_frags+0x97/0x6c0 net/core/skbuff.c:6193 sock_alloc_send_pskb+0x7a7/0x930 net/core/sock.c:2741 sock_alloc_send_skb include/net/sock.h:1888 [inline] mld_newpack.isra.0+0x1b9/0x770 net/ipv6/mcast.c:1748 add_grhead+0x295/0x340 net/ipv6/mcast.c:1851 add_grec+0x1053/0x1610 net/ipv6/mcast.c:1989 mld_send_cr net/ipv6/mcast.c:2115 [inline] mld_ifc_work+0x42c/0xe20 net/ipv6/mcast.c:2653 process_one_work+0x9bf/0x1750 kernel/workqueue.c:2293 worker_thread+0x669/0x1090 kernel/workqueue.c:2440 Memory state around the buggy address: ffff888026b24d80: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc ffff888026b24e00: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc >ffff888026b24e80: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ^ ffff888026b24f00: 00 00 00 fc fc fc fc fc fa fb fb fb fc fc fc fc ffff888026b24f80: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ==================================================================