Hello,

syzbot found the following issue on:

HEAD commit: 3b5e1590a267 Merge tag 'gpio-fixes-for-v5.18' of git://git.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1195135ef00000 kernel config: https://syzkaller.appspot.com/x/.config?x=902c5209311d387c dashboard link: https://syzkaller.appspot.com/bug?extid=6912c9592caca7ca0e7d compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+6912c9592caca7ca0e7d@syzkaller.appspotmail.com

================================================================== BUG: KASAN: use-after-free in __snd_rawmidi_transmit_ack+0x2cd/0x2f0 sound/core/rawmidi.c:1348 Read of size 8 at addr ffff888078b36410 by task kworker/1:1H/754

CPU: 1 PID: 754 Comm: kworker/1:1H Not tainted 5.18.0-rc7-syzkaller-00136-g3b5e1590a267 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_highpri snd_usbmidi_out_work Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0xeb/0x495 mm/kasan/report.c:313 print_report mm/kasan/report.c:429 [inline] kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491 __snd_rawmidi_transmit_ack+0x2cd/0x2f0 sound/core/rawmidi.c:1348 snd_rawmidi_transmit+0xae/0xf0 sound/core/rawmidi.c:1415 snd_usbmidi_standard_output+0x264/0xc10 sound/usb/midi.c:650 snd_usbmidi_do_output+0x200/0x510 sound/usb/midi.c:311 process_one_work+0x996/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e9/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 </TASK>

Allocated by task 9345: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:436 [inline] ____kasan_kmalloc mm/kasan/common.c:515 [inline] ____kasan_kmalloc mm/kasan/common.c:474 [inline] __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:524 kmalloc include/linux/slab.h:581 [inline] kzalloc include/linux/slab.h:714 [inline] snd_rawmidi_runtime_create sound/core/rawmidi.c:148 [inline] open_substream+0xe9/0x8b0 sound/core/rawmidi.c:306 rawmidi_open_priv+0x591/0x6f0 sound/core/rawmidi.c:357 snd_rawmidi_kernel_open+0x1b5/0x270 sound/core/rawmidi.c:392 midisynth_use+0xee/0x270 sound/core/seq/seq_midi.c:215 subscribe_port sound/core/seq/seq_ports.c:412 [inline] check_and_subscribe_port+0x89a/0xb80 sound/core/seq/seq_ports.c:495 snd_seq_port_connect+0x382/0x540 sound/core/seq/seq_ports.c:581 snd_seq_ioctl_subscribe_port+0x1fc/0x400 sound/core/seq/seq_clientmgr.c:1492 snd_seq_kernel_client_ctl+0x102/0x1e0 sound/core/seq/seq_clientmgr.c:2369 snd_seq_oss_midi_open+0x582/0x6e0 sound/core/seq/oss/seq_oss_midi.c:359 snd_seq_oss_synth_setup_midi+0x12d/0x530 sound/core/seq/oss/seq_oss_synth.c:269 snd_seq_oss_open+0x8c3/0xa80 sound/core/seq/oss/seq_oss_init.c:260 odev_open+0x6c/0x90 sound/core/seq/oss/seq_oss.c:128 soundcore_open+0x44e/0x620 sound/sound_core.c:593 chrdev_open+0x266/0x770 fs/char_dev.c:414 do_dentry_open+0x4a1/0x11e0 fs/open.c:824 do_open fs/namei.c:3476 [inline] path_openat+0x1c71/0x2910 fs/namei.c:3609 do_filp_open+0x1aa/0x400 fs/namei.c:3636 do_sys_openat2+0x16d/0x4c0 fs/open.c:1213 do_sys_open fs/open.c:1229 [inline] __do_sys_openat fs/open.c:1245 [inline] __se_sys_openat fs/open.c:1240 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1240 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae

Freed by task 9345: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:45 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free+0x166/0x1a0 mm/kasan/common.c:328 kasan_slab_free include/linux/kasan.h:200 [inline] slab_free_hook mm/slub.c:1728 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1754 slab_free mm/slub.c:3510 [inline] kfree+0xd6/0x4d0 mm/slub.c:4552 snd_rawmidi_runtime_free sound/core/rawmidi.c:177 [inline] close_substream.part.0+0x18d/0x720 sound/core/rawmidi.c:528 close_substream sound/core/rawmidi.c:507 [inline] rawmidi_release_priv+0x192/0x270 sound/core/rawmidi.c:547 snd_rawmidi_kernel_release+0x39/0xd0 sound/core/rawmidi.c:564 midisynth_unuse+0x45/0x80 sound/core/seq/seq_midi.c:244 unsubscribe_port sound/core/seq/seq_ports.c:437 [inline] __delete_and_unsubscribe_port+0x270/0x4c0 sound/core/seq/seq_ports.c:537 snd_seq_port_disconnect+0x41c/0x5d0 sound/core/seq/seq_ports.c:616 snd_seq_ioctl_unsubscribe_port+0x1fc/0x400 sound/core/seq/seq_clientmgr.c:1537 snd_seq_kernel_client_ctl+0x102/0x1e0 sound/core/seq/seq_clientmgr.c:2369 snd_seq_oss_midi_close+0x44f/0x4d0 sound/core/seq/oss/seq_oss_midi.c:404 snd_seq_oss_synth_reset+0x422/0x880 sound/core/seq/oss/seq_oss_synth.c:406 snd_seq_oss_reset+0x6f/0x290 sound/core/seq/oss/seq_oss_init.c:435 snd_seq_oss_release+0x78/0x1a0 sound/core/seq/oss/seq_oss_init.c:412 odev_release+0x4f/0x70 sound/core/seq/oss/seq_oss.c:144 __fput+0x277/0x9d0 fs/file_table.c:317 task_work_run+0xdd/0x1a0 kernel/task_work.c:164 get_signal+0x1c5/0x24c0 kernel/signal.c:2641 arch_do_signal_or_restart+0x82/0x20f0 arch/x86/kernel/signal.c:867 exit_to_user_mode_loop kernel/entry/common.c:166 [inline] exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:294 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff888078b36400 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 16 bytes inside of 512-byte region [ffff888078b36400, ffff888078b36600)

The buggy address belongs to the physical page: page:ffffea0001e2cd00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x78b34 head:ffffea0001e2cd00 order:2 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888010c41c80 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 2967, tgid 2967 (udevadm), ts 15461279103, free_ts 12532036824 prep_new_page mm/page_alloc.c:2441 [inline] get_page_from_freelist+0xba2/0x3e00 mm/page_alloc.c:4182 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5408 alloc_pages+0x1aa/0x310 mm/mempolicy.c:2272 alloc_slab_page mm/slub.c:1799 [inline] allocate_slab+0x26c/0x3c0 mm/slub.c:1944 new_slab mm/slub.c:2004 [inline] ___slab_alloc+0x8df/0xf20 mm/slub.c:3005 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3092 slab_alloc_node mm/slub.c:3183 [inline] __kmalloc_node_track_caller+0x2cb/0x360 mm/slub.c:4947 kmalloc_reserve net/core/skbuff.c:354 [inline] __alloc_skb+0xde/0x340 net/core/skbuff.c:426 alloc_skb include/linux/skbuff.h:1300 [inline] alloc_uevent_skb+0x7b/0x210 lib/kobject_uevent.c:290 uevent_net_broadcast_untagged lib/kobject_uevent.c:326 [inline] kobject_uevent_net_broadcast lib/kobject_uevent.c:409 [inline] kobject_uevent_env+0xc42/0x1660 lib/kobject_uevent.c:593 kobject_synth_uevent+0x701/0x850 lib/kobject_uevent.c:208 store_uevent+0x12/0x20 kernel/module.c:1166 module_attr_store+0x50/0x80 kernel/params.c:919 sysfs_kf_write+0x110/0x160 fs/sysfs/file.c:136 kernfs_fop_write_iter+0x3f8/0x610 fs/kernfs/file.c:291 call_write_iter include/linux/fs.h:2050 [inline] new_sync_write+0x38a/0x560 fs/read_write.c:504 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1356 [inline] free_pcp_prepare+0x549/0xd20 mm/page_alloc.c:1406 free_unref_page_prepare mm/page_alloc.c:3328 [inline] free_unref_page+0x19/0x6a0 mm/page_alloc.c:3423 free_contig_range+0xb1/0x180 mm/page_alloc.c:9418 destroy_args+0xa8/0x646 mm/debug_vm_pgtable.c:1018 debug_vm_pgtable+0x2a51/0x2ae3 mm/debug_vm_pgtable.c:1332 do_one_initcall+0x103/0x650 init/main.c:1298 do_initcall_level init/main.c:1371 [inline] do_initcalls init/main.c:1387 [inline] do_basic_setup init/main.c:1406 [inline] kernel_init_freeable+0x6b1/0x73a init/main.c:1613 kernel_init+0x1a/0x1d0 init/main.c:1502 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

Memory state around the buggy address: ffff888078b36300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888078b36380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc

ffff888078b36400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

^ ffff888078b36480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888078b36500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================

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