==================================================================
BUG: KASAN: use-after-free in kobject_get+0x113/0x120 lib/kobject.c:663
Read of size 1 at addr ffff88811a03403c by task syz.2.813/2597
CPU: 0 PID: 2597 Comm: syz.2.813 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
__dump_stack+0x21/0x30 lib/dump_stack.c:88
dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:427 [inline]
kasan_report+0x10f/0x150 mm/kasan/report.c:444
__asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:306
kobject_get+0x113/0x120 lib/kobject.c:663
get_device drivers/base/core.c:3518 [inline]
device_add+0x2f0/0xe90 drivers/base/core.c:3342
device_create_groups_vargs drivers/base/core.c:4118 [inline]
device_create+0x26c/0x300 drivers/base/core.c:4160
create_function_device+0x60/0x70 drivers/usb/gadget/configfs.c:31
create_alsa_device drivers/usb/gadget/function/f_midi.c:1262 [inline]
f_midi_alloc_inst+0x1a8/0x380 drivers/usb/gadget/function/f_midi.c:1303
try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline]
usb_get_function_instance+0xe2/0x2f0 drivers/usb/gadget/functions.c:44
function_make+0x118/0x350 drivers/usb/gadget/configfs.c:642
configfs_mkdir+0x50a/0x9c0 fs/configfs/dir.c:1329
vfs_mkdir+0x38b/0x590 fs/namei.c:4073
do_mkdirat+0x174/0x4d0 fs/namei.c:4098
__do_sys_mkdirat fs/namei.c:4113 [inline]
__se_sys_mkdirat fs/namei.c:4111 [inline]
__x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4111
x64_sys_call+0x37e/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:259
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f09b999a0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f09b83f3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f09b9c21fa0 RCX: 00007f09b999a0d9
RDX: 00000000000001ff RSI: 0000200000000100 RDI: ffffffffffffff9c
RBP: 00007f09b9a31024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f09b9c22038 R14: 00007f09b9c21fa0 R15: 00007ffcfdbb60d8
Allocated by task 2329:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:45 [inline]
set_alloc_info mm/kasan/common.c:433 [inline]
____kasan_kmalloc mm/kasan/common.c:512 [inline]
__kasan_kmalloc+0xd4/0x100 mm/kasan/common.c:521
kasan_kmalloc include/linux/kasan.h:227 [inline]
__kmalloc_track_caller+0x13c/0x2c0 mm/slub.c:4959
kmalloc_reserve net/core/skbuff.c:357 [inline]
__alloc_skb+0x210/0x730 net/core/skbuff.c:428
alloc_skb include/linux/skbuff.h:1183 [inline]
alloc_skb_with_frags+0xa8/0x620 net/core/skbuff.c:6207
sock_alloc_send_pskb+0x87f/0x9a0 net/core/sock.c:2542
sock_alloc_send_skb+0x32/0x40 net/core/sock.c:2559
__ip6_append_data+0x2500/0x37e0 net/ipv6/ip6_output.c:1596
ip6_make_skb+0x388/0x6e0 net/ipv6/ip6_output.c:1965
udpv6_sendmsg+0x1bc7/0x2690 net/ipv6/udp.c:1580
inet6_sendmsg+0xa5/0xc0 net/ipv6/af_inet6.c:660
sock_sendmsg_nosec net/socket.c:704 [inline]
__sock_sendmsg net/socket.c:716 [inline]
____sys_sendmsg+0x5be/0x8f0 net/socket.c:2436
___sys_sendmsg+0x236/0x2e0 net/socket.c:2490
__sys_sendmmsg+0x2ba/0x4e0 net/socket.c:2576
__do_sys_sendmmsg net/socket.c:2605 [inline]
__se_sys_sendmmsg net/socket.c:2602 [inline]
__x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2602
x64_sys_call+0x6c6/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:308
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
Freed by task 2329:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4a/0x70 mm/kasan/common.c:45
kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
____kasan_slab_free+0x125/0x160 mm/kasan/common.c:365
__kasan_slab_free+0x11/0x20 mm/kasan/common.c:373
kasan_slab_free include/linux/kasan.h:193 [inline]
slab_free_hook mm/slub.c:1728 [inline]
slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1754
slab_free mm/slub.c:3526 [inline]
kfree+0xc4/0x270 mm/slub.c:4588
skb_free_head net/core/skbuff.c:656 [inline]
skb_release_data+0x7bd/0xa20 net/core/skbuff.c:678
skb_release_all net/core/skbuff.c:743 [inline]
__kfree_skb net/core/skbuff.c:757 [inline]
kfree_skb_reason net/core/skbuff.c:778 [inline]
kfree_skb+0xb9/0x2f0 net/core/skbuff.c:792
ipip_tunnel_xmit+0x1fc/0x440 net/ipv4/ipip.c:311
__netdev_start_xmit include/linux/netdevice.h:5064 [inline]
netdev_start_xmit include/linux/netdevice.h:5078 [inline]
xmit_one net/core/dev.c:3670 [inline]
dev_hard_start_xmit+0x245/0x680 net/core/dev.c:3686
__dev_queue_xmit+0x17a3/0x2d60 net/core/dev.c:4313
dev_queue_xmit+0x17/0x20 net/core/dev.c:4355
neigh_connected_output+0x434/0x470 net/core/neighbour.c:1533
neigh_output include/net/neighbour.h:517 [inline]
ip6_finish_output2+0x10d0/0x1790 net/ipv6/ip6_output.c:130
__ip6_finish_output+0x621/0x7e0 net/ipv6/ip6_output.c:201
ip6_finish_output+0x31/0x220 net/ipv6/ip6_output.c:211
NF_HOOK_COND include/linux/netfilter.h:294 [inline]
ip6_output+0x1fa/0x410 net/ipv6/ip6_output.c:234
dst_output include/net/dst.h:453 [inline]
ip6_local_out+0x200/0x3c0 net/ipv6/output_core.c:161
ip6_send_skb+0xb6/0x1c0 net/ipv6/ip6_output.c:1885
udp_v6_send_skb+0x9e6/0x1450 net/ipv6/udp.c:1285
udpv6_sendmsg+0x1c01/0x2690 net/ipv6/udp.c:1586
inet6_sendmsg+0xa5/0xc0 net/ipv6/af_inet6.c:660
sock_sendmsg_nosec net/socket.c:704 [inline]
__sock_sendmsg net/socket.c:716 [inline]
____sys_sendmsg+0x5be/0x8f0 net/socket.c:2436
___sys_sendmsg+0x236/0x2e0 net/socket.c:2490
__sys_sendmmsg+0x2ba/0x4e0 net/socket.c:2576
__do_sys_sendmmsg net/socket.c:2605 [inline]
__se_sys_sendmmsg net/socket.c:2602 [inline]
__x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2602
x64_sys_call+0x6c6/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:308
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
The buggy address belongs to the object at ffff88811a034000
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 60 bytes inside of
1024-byte region [ffff88811a034000, ffff88811a034400)
The buggy address belongs to the page:
page:ffffea0004680c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11a030
head:ffffea0004680c00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 dead000000000100 dead000000000122 ffff888100043080
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 103, ts 4529139309, free_ts 0
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2607
prep_new_page+0x1c/0x110 mm/page_alloc.c:2613
get_page_from_freelist+0x2c3a/0x2cd0 mm/page_alloc.c:4487
__alloc_pages+0x1a2/0x460 mm/page_alloc.c:5824
alloc_slab_page mm/slub.c:-1 [inline]
allocate_slab mm/slub.c:1937 [inline]
new_slab+0xa0/0x4d0 mm/slub.c:2000
___slab_alloc+0x3ac/0x840 mm/slub.c:3033
__slab_alloc+0x49/0x90 mm/slub.c:3120
slab_alloc_node mm/slub.c:3211 [inline]
slab_alloc mm/slub.c:3255 [inline]
__kmalloc_track_caller+0x169/0x2c0 mm/slub.c:4954
kmalloc_reserve net/core/skbuff.c:357 [inline]
__alloc_skb+0x210/0x730 net/core/skbuff.c:428
alloc_skb include/linux/skbuff.h:1183 [inline]
netlink_alloc_large_skb net/netlink/af_netlink.c:1186 [inline]
netlink_sendmsg+0x611/0xb80 net/netlink/af_netlink.c:1902
sock_sendmsg_nosec net/socket.c:704 [inline]
__sock_sendmsg net/socket.c:716 [inline]
____sys_sendmsg+0x5be/0x8f0 net/socket.c:2436
___sys_sendmsg+0x236/0x2e0 net/socket.c:2490
__sys_sendmsg net/socket.c:2519 [inline]
__do_sys_sendmsg net/socket.c:2528 [inline]
__se_sys_sendmsg net/socket.c:2526 [inline]
__x64_sys_sendmsg+0x201/0x2d0 net/socket.c:2526
x64_sys_call+0x4b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:47
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
page_owner free stack trace missing
Memory state around the buggy address:
ffff88811a033f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811a033f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88811a034000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811a034080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811a034100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
------------[ cut here ]------------
kobject: '' (ffff88811a034000): is not initialized, yet kobject_get() is being called.
WARNING: CPU: 1 PID: 2597 at lib/kobject.c:666 kobject_get+0x7c/0x120 lib/kobject.c:664
configfs_mkdir+0x50a/0x9c0 fs/configfs/dir.c:1329
vfs_mkdir+0x38b/0x590 fs/namei.c:4073
do_mkdirat+0x174/0x4d0 fs/namei.c:4098
__do_sys_mkdirat fs/namei.c:4113 [inline]
__se_sys_mkdirat fs/namei.c:4111 [inline]
__x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4111
x64_sys_call+0x37e/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:259
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f09b999a0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f09b83f3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f09b9c21fa0 RCX: 00007f09b999a0d9
RDX: 00000000000001ff RSI: 0000200000000100 RDI: ffffffffffffff9c
RBP: 00007f09b9a31024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f09b9c22038 R14: 00007f09b9c21fa0 R15: 00007ffcfdbb60d8
---[ end trace 07f7494a004bb668 ]---
------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 2597 at lib/refcount.c:25 refcount_warn_saturate+0x104/0x1a0 lib/refcount.c:25
Modules linked in:
CPU: 1 PID: 2597 Comm: syz.2.813 Tainted: G B W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:refcount_warn_saturate+0x104/0x1a0 lib/refcount.c:25
Code: 04 01 48 c7 c7 c0 4a 63 85 e8 58 67 5a 02 0f 0b eb df e8 ef 7f 19 ff c6 05 ab f4 95 04 01 48 c7 c7 00 4a 63 85 e8 3c 67 5a 02 <0f> 0b eb c3 e8 d3 7f 19 ff c6 05 90 f4 95 04 01 48 c7 c7 60 4a 63
RSP: 0018:ffffc9000125f9f8 EFLAGS: 00010246
RAX: 1d4c933dd1e38100 RBX: 0000000000000002 RCX: 0000000000080000
RDX: ffffc90001379000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc9000125fa08 R08: ffff8881f7127493 R09: 1ffff1103ee24e92
R10: dffffc0000000000 R11: ffffed103ee24e93 R12: 1ffff11021b8a80e
R13: dffffc0000000000 R14: 0000000000000002 R15: 0000000000000000
FS: 00007f09b83f36c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31b10ff8 CR3: 000000013a268000 CR4: 00000000003506a0
Call Trace:
__refcount_add include/linux/refcount.h:-1 [inline]
__refcount_inc include/linux/refcount.h:250 [inline]
refcount_inc include/linux/refcount.h:267 [inline]
kref_get include/linux/kref.h:45 [inline]
kobject_get+0xfb/0x120 lib/kobject.c:667
get_device drivers/base/core.c:3518 [inline]
device_add+0x2f0/0xe90 drivers/base/core.c:3342
device_create_groups_vargs drivers/base/core.c:4118 [inline]
device_create+0x26c/0x300 drivers/base/core.c:4160
create_function_device+0x60/0x70 drivers/usb/gadget/configfs.c:31
create_alsa_device drivers/usb/gadget/function/f_midi.c:1262 [inline]
f_midi_alloc_inst+0x1a8/0x380 drivers/usb/gadget/function/f_midi.c:1303
try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline]
usb_get_function_instance+0xe2/0x2f0 drivers/usb/gadget/functions.c:44
function_make+0x118/0x350 drivers/usb/gadget/configfs.c:642
configfs_mkdir+0x50a/0x9c0 fs/configfs/dir.c:1329
vfs_mkdir+0x38b/0x590 fs/namei.c:4073
do_mkdirat+0x174/0x4d0 fs/namei.c:4098
__do_sys_mkdirat fs/namei.c:4113 [inline]
__se_sys_mkdirat fs/namei.c:4111 [inline]
__x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4111
x64_sys_call+0x37e/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:259
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f09b999a0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f09b83f3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f09b9c21fa0 RCX: 00007f09b999a0d9
RDX: 00000000000001ff RSI: 0000200000000100 RDI: ffffffffffffff9c
RBP: 00007f09b9a31024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f09b9c22038 R14: 00007f09b9c21fa0 R15: 00007ffcfdbb60d8
---[ end trace 07f7494a004bb669 ]---
------------[ cut here ]------------
kobject: '' (ffff88811a034000): is not initialized, yet kobject_get() is being called.
WARNING: CPU: 1 PID: 2597 at lib/kobject.c:666 kobject_get lib/kobject.c:664 [inline]
WARNING: CPU: 1 PID: 2597 at lib/kobject.c:666 kobject_add_internal+0x12e/0xde0 lib/kobject.c:248
Modules linked in:
CPU: 1 PID: 2597 Comm: syz.2.813 Tainted: G B W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:kobject_get lib/kobject.c:664 [inline]
RIP: 0010:kobject_add_internal+0x12e/0xde0 lib/kobject.c:248
Code: b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 4c 89 e7 e8 a5 2b 39 ff 49 8b 34 24 48 c7 c7 a0 c5 64 85 4c 89 e2 e8 82 a3 3a 02 <0f> 0b e9 04 01 00 00 e8 16 bc f9 fe b8 fe ff ff ff e9 b0 09 00 00
RSP: 0018:ffffc9000125f898 EFLAGS: 00010246
RAX: 1d4c933dd1e38100 RBX: ffff888122771e00 RCX: 0000000000080000
RDX: ffffc90001379000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc9000125f8f0 R08: ffff8881f7132f3f R09: 1ffff1103ee265e7
R10: dffffc0000000000 R11: ffffed103ee265e8 R12: ffff88811a034000
R13: ffff888122771e18 R14: 0000000000000000 R15: 1ffff110244ee3c0
FS: 00007f09b83f36c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31b10ff8 CR3: 000000013a268000 CR4: 00000000003506a0
Call Trace:
kobject_add_varg lib/kobject.c:398 [inline]
kobject_add+0x165/0x230 lib/kobject.c:450
class_dir_create_and_add drivers/base/core.c:2976 [inline]
get_device_parent+0x3a6/0x410 drivers/base/core.c:3031
device_add+0x308/0xe90 drivers/base/core.c:3343
device_create_groups_vargs drivers/base/core.c:4118 [inline]
device_create+0x26c/0x300 drivers/base/core.c:4160
create_function_device+0x60/0x70 drivers/usb/gadget/configfs.c:31
create_alsa_device drivers/usb/gadget/function/f_midi.c:1262 [inline]
f_midi_alloc_inst+0x1a8/0x380 drivers/usb/gadget/function/f_midi.c:1303
try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline]
usb_get_function_instance+0xe2/0x2f0 drivers/usb/gadget/functions.c:44
function_make+0x118/0x350 drivers/usb/gadget/configfs.c:642
configfs_mkdir+0x50a/0x9c0 fs/configfs/dir.c:1329
vfs_mkdir+0x38b/0x590 fs/namei.c:4073
do_mkdirat+0x174/0x4d0 fs/namei.c:4098
__do_sys_mkdirat fs/namei.c:4113 [inline]
__se_sys_mkdirat fs/namei.c:4111 [inline]
__x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4111
x64_sys_call+0x37e/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:259
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f09b999a0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f09b83f3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f09b9c21fa0 RCX: 00007f09b999a0d9
RDX: 00000000000001ff RSI: 0000200000000100 RDI: ffffffffffffff9c
RBP: 00007f09b9a31024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f09b9c22038 R14: 00007f09b9c21fa0 R15: 00007ffcfdbb60d8
---[ end trace 07f7494a004bb66a ]---
------------[ cut here ]------------
refcount_t: saturated; leaking memory.
WARNING: CPU: 1 PID: 2597 at lib/refcount.c:22 refcount_warn_saturate+0x158/0x1a0 lib/refcount.c:22
Modules linked in:
CPU: 1 PID: 2597 Comm: syz.2.813 Tainted: G B W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:refcount_warn_saturate+0x158/0x1a0 lib/refcount.c:22
Code: 04 01 48 c7 c7 a0 49 63 85 e8 04 67 5a 02 0f 0b eb 8b e8 9b 7f 19 ff c6 05 56 f4 95 04 01 48 c7 c7 a0 49 63 85 e8 e8 66 5a 02 <0f> 0b e9 6c ff ff ff e8 7c 7f 19 ff c6 05 3b f4 95 04 01 48 c7 c7
RSP: 0018:ffffc9000125f878 EFLAGS: 00010246
RAX: 1d4c933dd1e38100 RBX: 0000000000000001 RCX: 0000000000080000
RDX: ffffc90001379000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc9000125f888 R08: ffff8881f7132f3f R09: 1ffff1103ee265e7
R10: dffffc0000000000 R11: ffffed103ee265e8 R12: 00000000c0000000
R13: ffff888122771e18 R14: 0000000000000001 R15: ffff88811a034038
FS: 00007f09b83f36c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31b10ff8 CR3: 000000013a268000 CR4: 00000000003506a0
Call Trace:
__refcount_add include/linux/refcount.h:-1 [inline]
__refcount_inc include/linux/refcount.h:250 [inline]
refcount_inc include/linux/refcount.h:267 [inline]
kref_get include/linux/kref.h:45 [inline]
kobject_get lib/kobject.c:667 [inline]
kobject_add_internal+0xc44/0xde0 lib/kobject.c:248
kobject_add_varg lib/kobject.c:398 [inline]
kobject_add+0x165/0x230 lib/kobject.c:450
class_dir_create_and_add drivers/base/core.c:2976 [inline]
get_device_parent+0x3a6/0x410 drivers/base/core.c:3031
device_add+0x308/0xe90 drivers/base/core.c:3343
device_create_groups_vargs drivers/base/core.c:4118 [inline]
device_create+0x26c/0x300 drivers/base/core.c:4160
create_function_device+0x60/0x70 drivers/usb/gadget/configfs.c:31
create_alsa_device drivers/usb/gadget/function/f_midi.c:1262 [inline]
f_midi_alloc_inst+0x1a8/0x380 drivers/usb/gadget/function/f_midi.c:1303
try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline]
usb_get_function_instance+0xe2/0x2f0 drivers/usb/gadget/functions.c:44
function_make+0x118/0x350 drivers/usb/gadget/configfs.c:642
configfs_mkdir+0x50a/0x9c0 fs/configfs/dir.c:1329
vfs_mkdir+0x38b/0x590 fs/namei.c:4073
do_mkdirat+0x174/0x4d0 fs/namei.c:4098
__do_sys_mkdirat fs/namei.c:4113 [inline]
__se_sys_mkdirat fs/namei.c:4111 [inline]
__x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4111
x64_sys_call+0x37e/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:259
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f09b999a0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f09b83f3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f09b9c21fa0 RCX: 00007f09b999a0d9
RDX: 00000000000001ff RSI: 0000200000000100 RDI: ffffffffffffff9c
RBP: 00007f09b9a31024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f09b9c22038 R14: 00007f09b9c21fa0 R15: 00007ffcfdbb60d8
---[ end trace 07f7494a004bb66b ]---
------------[ cut here ]------------
kobject: '' (ffff88811a034000): is not initialized, yet kobject_put() is being called.
WARNING: CPU: 1 PID: 2597 at lib/kobject.c:760 kobject_put+0x8a/0x270 lib/kobject.c:758
Modules linked in:
CPU: 1 PID: 2597 Comm: syz.2.813 Tainted: G B W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:kobject_put+0x8a/0x270 lib/kobject.c:758
Code: 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 f8 42 39 ff 48 8b 33 48 c7 c7 20 c6 64 85 48 89 da e8 d6 ba 3a 02 <0f> 0b eb 0f e8 6d d3 f9 fe e9 7c 01 00 00 e8 63 d3 f9 fe 4c 8d 7b
RSP: 0018:ffffc9000125f860 EFLAGS: 00010246
RAX: 1d4c933dd1e38100 RBX: ffff88811a034000 RCX: 0000000000080000
RDX: ffffc90001379000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc9000125f888 R08: ffffc9000125f2c7 R09: 1ffff9200024be58
R10: dffffc0000000000 R11: fffff5200024be59 R12: ffff88811a034000
R13: ffff88811a03403c R14: 1ffff11023406807 R15: 0000000000000000
FS: 00007f09b83f36c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31b10ff8 CR3: 000000013a268000 CR4: 00000000003506a0
Call Trace:
kobject_add_internal+0xb52/0xde0 lib/kobject.c:266
kobject_add_varg lib/kobject.c:398 [inline]
kobject_add+0x165/0x230 lib/kobject.c:450
class_dir_create_and_add drivers/base/core.c:2976 [inline]
get_device_parent+0x3a6/0x410 drivers/base/core.c:3031
device_add+0x308/0xe90 drivers/base/core.c:3343
device_create_groups_vargs drivers/base/core.c:4118 [inline]
device_create+0x26c/0x300 drivers/base/core.c:4160
create_function_device+0x60/0x70 drivers/usb/gadget/configfs.c:31
create_alsa_device drivers/usb/gadget/function/f_midi.c:1262 [inline]
f_midi_alloc_inst+0x1a8/0x380 drivers/usb/gadget/function/f_midi.c:1303
try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline]
usb_get_function_instance+0xe2/0x2f0 drivers/usb/gadget/functions.c:44
function_make+0x118/0x350 drivers/usb/gadget/configfs.c:642
configfs_mkdir+0x50a/0x9c0 fs/configfs/dir.c:1329
vfs_mkdir+0x38b/0x590 fs/namei.c:4073
do_mkdirat+0x174/0x4d0 fs/namei.c:4098
__do_sys_mkdirat fs/namei.c:4113 [inline]
__se_sys_mkdirat fs/namei.c:4111 [inline]
__x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4111
x64_sys_call+0x37e/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:259
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f09b999a0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f09b83f3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f09b9c21fa0 RCX: 00007f09b999a0d9
RDX: 00000000000001ff RSI: 0000200000000100 RDI: ffffffffffffff9c
RBP: 00007f09b9a31024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f09b9c22038 R14: 00007f09b9c21fa0 R15: 00007ffcfdbb60d8
---[ end trace 07f7494a004bb66c ]---
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 2597 at lib/refcount.c:28 refcount_warn_saturate+0x120/0x1a0 lib/refcount.c:28
Modules linked in:
CPU: 1 PID: 2597 Comm: syz.2.813 Tainted: G B W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:refcount_warn_saturate+0x120/0x1a0 lib/refcount.c:28
Code: 04 01 48 c7 c7 00 4a 63 85 e8 3c 67 5a 02 0f 0b eb c3 e8 d3 7f 19 ff c6 05 90 f4 95 04 01 48 c7 c7 60 4a 63 85 e8 20 67 5a 02 <0f> 0b eb a7 e8 b7 7f 19 ff c6 05 71 f4 95 04 01 48 c7 c7 a0 49 63
RSP: 0018:ffffc9000125f840 EFLAGS: 00010246
RAX: 1d4c933dd1e38100 RBX: 0000000000000003 RCX: 0000000000080000
RDX: ffffc90001379000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc9000125f850 R08: ffffc9000125f2a7 R09: 1ffff9200024be54
R10: dffffc0000000000 R11: fffff5200024be55 R12: 00000000c0000000
R13: ffff88811a03403c R14: 0000000000000003 R15: ffff88811a034038
FS: 00007f09b83f36c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31b10ff8 CR3: 000000013a268000 CR4: 00000000003506a0
Call Trace:
__refcount_sub_and_test include/linux/refcount.h:283 [inline]
__refcount_dec_and_test include/linux/refcount.h:315 [inline]
refcount_dec_and_test include/linux/refcount.h:333 [inline]
kref_put include/linux/kref.h:64 [inline]
kobject_put+0x231/0x270 lib/kobject.c:761
kobject_add_internal+0xb52/0xde0 lib/kobject.c:266
kobject_add_varg lib/kobject.c:398 [inline]
kobject_add+0x165/0x230 lib/kobject.c:450
class_dir_create_and_add drivers/base/core.c:2976 [inline]
get_device_parent+0x3a6/0x410 drivers/base/core.c:3031
device_add+0x308/0xe90 drivers/base/core.c:3343
device_create_groups_vargs drivers/base/core.c:4118 [inline]
device_create+0x26c/0x300 drivers/base/core.c:4160
create_function_device+0x60/0x70 drivers/usb/gadget/configfs.c:31
create_alsa_device drivers/usb/gadget/function/f_midi.c:1262 [inline]
f_midi_alloc_inst+0x1a8/0x380 drivers/usb/gadget/function/f_midi.c:1303
try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline]
usb_get_function_instance+0xe2/0x2f0 drivers/usb/gadget/functions.c:44
function_make+0x118/0x350 drivers/usb/gadget/configfs.c:642
configfs_mkdir+0x50a/0x9c0 fs/configfs/dir.c:1329
vfs_mkdir+0x38b/0x590 fs/namei.c:4073
do_mkdirat+0x174/0x4d0 fs/namei.c:4098
__do_sys_mkdirat fs/namei.c:4113 [inline]
__se_sys_mkdirat fs/namei.c:4111 [inline]
__x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4111
x64_sys_call+0x37e/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:259
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f09b999a0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f09b83f3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f09b9c21fa0 RCX: 00007f09b999a0d9
RDX: 00000000000001ff RSI: 0000200000000100 RDI: ffffffffffffff9c
RBP: 00007f09b9a31024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f09b9c22038 R14: 00007f09b9c21fa0 R15: 00007ffcfdbb60d8
---[ end trace 07f7494a004bb66d ]---
kobject_add_internal failed for android_usb (error: -2 parent: )
------------[ cut here ]------------
kobject: '' (ffff88811a034000): is not initialized, yet kobject_put() is being called.
WARNING: CPU: 1 PID: 2597 at lib/kobject.c:760 kobject_put+0x8a/0x270 lib/kobject.c:758
Modules linked in:
CPU: 1 PID: 2597 Comm: syz.2.813 Tainted: G B W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:kobject_put+0x8a/0x270 lib/kobject.c:758
Code: 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 f8 42 39 ff 48 8b 33 48 c7 c7 20 c6 64 85 48 89 da e8 d6 ba 3a 02 <0f> 0b eb 0f e8 6d d3 f9 fe e9 7c 01 00 00 e8 63 d3 f9 fe 4c 8d 7b
RSP: 0018:ffffc9000125fa08 EFLAGS: 00010246
RAX: 1d4c933dd1e38100 RBX: ffff88811a034000 RCX: 0000000000080000
RDX: ffffc90001379000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc9000125fa30 R08: ffff8881f7132f3f R09: 1ffff1103ee265e7
R10: dffffc0000000000 R11: ffffed103ee265e8 R12: ffff88810dc54068
R13: ffff88811a03403c R14: 1ffff11023406807 R15: 0000000000000000
FS: 00007f09b83f36c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31b10ff8 CR3: 000000013a268000 CR4: 00000000003506a0
Call Trace:
put_device drivers/base/core.c:3530 [inline]
device_add+0x985/0xe90 drivers/base/core.c:3475
device_create_groups_vargs drivers/base/core.c:4118 [inline]
device_create+0x26c/0x300 drivers/base/core.c:4160
create_function_device+0x60/0x70 drivers/usb/gadget/configfs.c:31
create_alsa_device drivers/usb/gadget/function/f_midi.c:1262 [inline]
f_midi_alloc_inst+0x1a8/0x380 drivers/usb/gadget/function/f_midi.c:1303
try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline]
usb_get_function_instance+0xe2/0x2f0 drivers/usb/gadget/functions.c:44
function_make+0x118/0x350 drivers/usb/gadget/configfs.c:642
configfs_mkdir+0x50a/0x9c0 fs/configfs/dir.c:1329
vfs_mkdir+0x38b/0x590 fs/namei.c:4073
do_mkdirat+0x174/0x4d0 fs/namei.c:4098
__do_sys_mkdirat fs/namei.c:4113 [inline]
__se_sys_mkdirat fs/namei.c:4111 [inline]
__x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4111
x64_sys_call+0x37e/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:259
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f09b999a0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f09b83f3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f09b9c21fa0 RCX: 00007f09b999a0d9
RDX: 00000000000001ff RSI: 0000200000000100 RDI: ffffffffffffff9c
RBP: 00007f09b9a31024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f09b9c22038 R14: 00007f09b9c21fa0 R15: 00007ffcfdbb60d8
---[ end trace 07f7494a004bb66e ]---