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BUG: KASAN: use-after-free in __list_add_valid+0x8f/0xb0 lib/list_debug.c:26
Read of size 8 at addr ffff8880a7bed938 by task syz-executor.3/7727

CPU: 1 PID: 7727 Comm: syz-executor.3 Not tainted 5.4.0-rc2+ #0
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+0x113/0x167 lib/dump_stack.c:113
 print_address_description.constprop.8.cold.10+0x9/0x31d mm/kasan/report.c:374
 __kasan_report.cold.11+0x1b/0x3a mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:634
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
 __list_add_valid+0x8f/0xb0 lib/list_debug.c:26
 __list_add include/linux/list.h:60 [inline]
 list_add_tail include/linux/list.h:93 [inline]
 snd_timer_open+0x1db/0xf50 sound/core/timer.c:268
 snd_timer_user_tselect sound/core/timer.c:1738 [inline]
 __snd_timer_user_ioctl.isra.27+0xc8d/0x1de0 sound/core/timer.c:2008
 snd_timer_user_ioctl+0x77/0xa4 sound/core/timer.c:2038
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0x196/0x1150 fs/ioctl.c:696
 ksys_ioctl+0x62/0x90 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:718
 do_syscall_64+0xca/0x5d0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45a219
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007feaeabf5c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a219
RDX: 0000000020029fcc RSI: 0000000040345410 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007feaeabf66d4
R13: 00000000004cf428 R14: 00000000004d9760 R15: 00000000ffffffff

Allocated by task 7724:
 save_stack+0x21/0x90 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 __kasan_kmalloc.constprop.9+0xc7/0xd0 mm/kasan/common.c:510
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:524
 kmem_cache_alloc_trace+0x15b/0x780 mm/slab.c:3550
 kmalloc include/linux/slab.h:552 [inline]
 kzalloc include/linux/slab.h:686 [inline]
 snd_timer_instance_new+0x46/0x2c0 sound/core/timer.c:96
 snd_timer_user_tselect sound/core/timer.c:1725 [inline]
 __snd_timer_user_ioctl.isra.27+0xb0c/0x1de0 sound/core/timer.c:2008
 snd_timer_user_ioctl+0x77/0xa4 sound/core/timer.c:2038
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0x196/0x1150 fs/ioctl.c:696
 ksys_ioctl+0x62/0x90 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:718
 do_syscall_64+0xca/0x5d0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 7724:
 save_stack+0x21/0x90 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 kasan_set_free_info mm/kasan/common.c:332 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:471
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:480
 __cache_free mm/slab.c:3425 [inline]
 kfree+0x108/0x2c0 mm/slab.c:3756
 snd_timer_instance_free+0x62/0x80 sound/core/timer.c:120
 snd_timer_user_tselect sound/core/timer.c:1740 [inline]
 __snd_timer_user_ioctl.isra.27+0xcbe/0x1de0 sound/core/timer.c:2008
 snd_timer_user_ioctl+0x77/0xa4 sound/core/timer.c:2038
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0x196/0x1150 fs/ioctl.c:696
 ksys_ioctl+0x62/0x90 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:718
 do_syscall_64+0xca/0x5d0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880a7bed8c0
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 120 bytes inside of
 256-byte region [ffff8880a7bed8c0, ffff8880a7bed9c0)
The buggy address belongs to the page:
page:ffffea00029efb40 refcount:1 mapcount:0 mapping:ffff8880aa4008c0 index:0x0
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea00026c4688 ffffea00023b8588 ffff8880aa4008c0
raw: 0000000000000000 ffff8880a7bed000 000000010000000c 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a7bed800: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
 ffff8880a7bed880: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff8880a7bed900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff8880a7bed980: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8880a7beda00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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