[Android 5.15] KASAN: use-after-free Read in device_create
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syzbot
Jul 30, 2026, 12:16:45 PM (2 days ago) Jul 30
to syzkaller-a...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 61d896ee2a80 Revert "hdlc_ppp: sync per-proto timers befor..
git tree: android13-5.15-lts
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1003649e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=43676e801f1929a9
dashboard link: https://syzkaller.appspot.com/bug?extid=1573af6fa2e41a961e8e
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=127c97b1580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10083632580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bcb85cf50754/disk-61d896ee.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7e4ac22ab0e5/vmlinux-61d896ee.xz
kernel image: https://storage.googleapis.com/syzbot-assets/14b47a248e31/bzImage-61d896ee.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1573af...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in kobject_get+0x113/0x120 lib/kobject.c:663
Read of size 1 at addr ffff88810b07083c by task syz-executor360/303
CPU: 0 PID: 303 Comm: syz-executor360 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
<TASK>
__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: 0033:0x7fbe667cdc79
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd10a8fa78 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 0000200000000100 RCX: 00007fbe667cdc79
RDX: 00000000000001ff RSI: 0000200000000100 RDI: 00000000ffffff9c
RBP: 0032672f74656764 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd10a8fbb8
R13: 0000000000000002 R14: 00007fbe6685eca0 R15: 0000000000000002
</TASK>
Allocated by task 303:
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]
kmem_cache_alloc_trace+0x119/0x270 mm/slub.c:3274
kmalloc include/linux/slab.h:619 [inline]
kzalloc include/linux/slab.h:750 [inline]
device_create_groups_vargs drivers/base/core.c:4100 [inline]
device_create+0x13a/0x300 drivers/base/core.c:4160
android_device_create drivers/usb/gadget/configfs.c:1788 [inline]
gadgets_make+0x816/0xa70 drivers/usb/gadget/configfs.c:1885
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_mkdir fs/namei.c:4118 [inline]
__se_sys_mkdir fs/namei.c:4116 [inline]
__x64_sys_mkdir+0x6e/0x80 fs/namei.c:4116
x64_sys_call+0x124/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:84
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 303:
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
device_create_release+0x15/0x20 drivers/base/core.c:4085
device_release+0x96/0x1c0 drivers/base/core.c:-1
kobject_cleanup lib/kobject.c:713 [inline]
kobject_release lib/kobject.c:744 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x18a/0x270 lib/kobject.c:761
put_device drivers/base/core.c:3530 [inline]
device_unregister drivers/base/core.c:3656 [inline]
device_destroy+0xb4/0xf0 drivers/base/core.c:4226
android_device_destroy drivers/usb/gadget/configfs.c:1820 [inline]
gadgets_drop+0xa0/0xd0 drivers/usb/gadget/configfs.c:1901
client_drop_item fs/configfs/dir.c:933 [inline]
configfs_rmdir+0x871/0x960 fs/configfs/dir.c:1536
vfs_rmdir+0x1ae/0x450 fs/namei.c:4157
do_rmdir+0x261/0x6b0 fs/namei.c:4218
__do_sys_rmdir fs/namei.c:4237 [inline]
__se_sys_rmdir fs/namei.c:4235 [inline]
__x64_sys_rmdir+0x49/0x50 fs/namei.c:4235
x64_sys_call+0x25f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:85
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 ffff88810b070800
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 60 bytes inside of
1024-byte region [ffff88810b070800, ffff88810b070c00)
The buggy address belongs to the page:
page:ffffea00042c1c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10b070
head:ffffea00042c1c00 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 0xd2000(__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, ts 2031452132, 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+0x16a/0x2c0 mm/slub.c:4432
__kmalloc_node include/linux/slab.h:487 [inline]
kmalloc_node include/linux/slab.h:642 [inline]
kzalloc_node include/linux/slab.h:761 [inline]
blk_mq_alloc_hctx block/blk-mq.c:2841 [inline]
blk_mq_alloc_and_init_hctx block/blk-mq.c:3255 [inline]
blk_mq_realloc_hw_ctxs+0x40d/0x1660 block/blk-mq.c:3307
blk_mq_init_allocated_queue+0x3ea/0x1770 block/blk-mq.c:3368
blk_mq_init_queue_data block/blk-mq.c:3203 [inline]
blk_mq_init_queue+0x6c/0xd0 block/blk-mq.c:3213
scsi_alloc_sdev+0x66c/0x9c0 drivers/scsi/scsi_scan.c:319
scsi_probe_and_add_lun+0x180/0x35d0 drivers/scsi/scsi_scan.c:1156
__scsi_scan_target+0x1d2/0xb70 drivers/scsi/scsi_scan.c:1637
scsi_scan_channel drivers/scsi/scsi_scan.c:1725 [inline]
scsi_scan_host_selected+0x34e/0x600 drivers/scsi/scsi_scan.c:1754
do_scsi_scan_host drivers/scsi/scsi_scan.c:1893 [inline]
scsi_scan_host+0x39e/0x670 drivers/scsi/scsi_scan.c:1923
page_owner free stack trace missing
Memory state around the buggy address:
ffff88810b070700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88810b070780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88810b070800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88810b070880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88810b070900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 0 PID: 303 at lib/refcount.c:25 refcount_warn_saturate+0x104/0x1a0 lib/refcount.c:25
Modules linked in:
CPU: 0 PID: 303 Comm: syz-executor360 Tainted: G B 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 80 47 63 85 e8 c8 47 5a 02 0f 0b eb df e8 5f 80 19 ff c6 05 1b ea 95 04 01 48 c7 c7 c0 46 63 85 e8 ac 47 5a 02 <0f> 0b eb c3 e8 43 80 19 ff c6 05 00 ea 95 04 01 48 c7 c7 20 47 63
RSP: 0018:ffffc900009979f8 EFLAGS: 00010246
RAX: ec8ae682d7094700 RBX: 0000000000000002 RCX: ffff88811b8862c0
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffc90000997a08 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000132ef0 R12: 1ffff1102160b30e
R13: dffffc0000000000 R14: 0000000000000002 R15: 0000000000000000
FS: 0000555566f423c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f90f3de76e8 CR3: 00000001244c9000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__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: 0033:0x7fbe667cdc79
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd10a8fa78 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 0000200000000100 RCX: 00007fbe667cdc79
RDX: 00000000000001ff RSI: 0000200000000100 RDI: 00000000ffffff9c
RBP: 0032672f74656764 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd10a8fbb8
R13: 0000000000000002 R14: 00007fbe6685eca0 R15: 0000000000000002
</TASK>
---[ end trace e491d44357f168b1 ]---
------------[ cut here ]------------
refcount_t: saturated; leaking memory.
WARNING: CPU: 0 PID: 303 at lib/refcount.c:22 refcount_warn_saturate+0x158/0x1a0 lib/refcount.c:22
Modules linked in:
CPU: 0 PID: 303 Comm: syz-executor360 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 60 46 63 85 e8 74 47 5a 02 0f 0b eb 8b e8 0b 80 19 ff c6 05 c6 e9 95 04 01 48 c7 c7 60 46 63 85 e8 58 47 5a 02 <0f> 0b e9 6c ff ff ff e8 ec 7f 19 ff c6 05 ab e9 95 04 01 48 c7 c7
RSP: 0018:ffffc900009978b8 EFLAGS: 00010246
RAX: ec8ae682d7094700 RBX: 0000000000000001 RCX: ffff88811b8862c0
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffc900009978c8 R08: ffffc90000997327 R09: 1ffff92000132e64
R10: dffffc0000000000 R11: fffff52000132e65 R12: 00000000c0000000
R13: ffff88810b059818 R14: 0000000000000001 R15: ffff88810b070838
FS: 0000555566f423c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f90f3de76e8 CR3: 00000001244c9000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__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
device_add+0x398/0xe90 drivers/base/core.c:3357
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: 0033:0x7fbe667cdc79
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd10a8fa78 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 0000200000000100 RCX: 00007fbe667cdc79
RDX: 00000000000001ff RSI: 0000200000000100 RDI: 00000000ffffff9c
RBP: 0032672f74656764 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd10a8fbb8
R13: 0000000000000002 R14: 00007fbe6685eca0 R15: 0000000000000002
</TASK>
---[ end trace e491d44357f168b2 ]---
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 303 at lib/refcount.c:28 refcount_warn_saturate+0x120/0x1a0 lib/refcount.c:28
Modules linked in:
CPU: 0 PID: 303 Comm: syz-executor360 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 c0 46 63 85 e8 ac 47 5a 02 0f 0b eb c3 e8 43 80 19 ff c6 05 00 ea 95 04 01 48 c7 c7 20 47 63 85 e8 90 47 5a 02 <0f> 0b eb a7 e8 27 80 19 ff c6 05 e1 e9 95 04 01 48 c7 c7 60 46 63
RSP: 0018:ffffc90000997880 EFLAGS: 00010246
RAX: ec8ae682d7094700 RBX: 0000000000000003 RCX: ffff88811b8862c0
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffc90000997890 R08: ffff8881f7032f3f R09: 1ffff1103ee065e7
R10: dffffc0000000000 R11: ffffed103ee065e8 R12: 00000000c0000000
R13: ffff88810b07083c R14: 0000000000000003 R15: ffff88810b070838
FS: 0000555566f423c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f90f3de76e8 CR3: 00000001244c9000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__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
device_add+0x398/0xe90 drivers/base/core.c:3357
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: 0033:0x7fbe667cdc79
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd10a8fa78 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 0000200000000100 RCX: 00007fbe667cdc79
RDX: 00000000000001ff RSI: 0000200000000100 RDI: 00000000ffffff9c
RBP: 0032672f74656764 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd10a8fbb8
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
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If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
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#syz dup: exact-subject-of-another-report
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#syz undup
syzbot found the following issue on:
HEAD commit: 61d896ee2a80 Revert "hdlc_ppp: sync per-proto timers befor..
git tree: android13-5.15-lts
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1003649e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=43676e801f1929a9
dashboard link: https://syzkaller.appspot.com/bug?extid=1573af6fa2e41a961e8e
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=127c97b1580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10083632580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bcb85cf50754/disk-61d896ee.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7e4ac22ab0e5/vmlinux-61d896ee.xz
kernel image: https://storage.googleapis.com/syzbot-assets/14b47a248e31/bzImage-61d896ee.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1573af...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in kobject_get+0x113/0x120 lib/kobject.c:663
Read of size 1 at addr ffff88810b07083c by task syz-executor360/303
CPU: 0 PID: 303 Comm: syz-executor360 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
<TASK>
__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: 0033:0x7fbe667cdc79
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd10a8fa78 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 0000200000000100 RCX: 00007fbe667cdc79
RDX: 00000000000001ff RSI: 0000200000000100 RDI: 00000000ffffff9c
RBP: 0032672f74656764 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd10a8fbb8
R13: 0000000000000002 R14: 00007fbe6685eca0 R15: 0000000000000002
</TASK>
Allocated by task 303:
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]
kmem_cache_alloc_trace+0x119/0x270 mm/slub.c:3274
kmalloc include/linux/slab.h:619 [inline]
kzalloc include/linux/slab.h:750 [inline]
device_create_groups_vargs drivers/base/core.c:4100 [inline]
device_create+0x13a/0x300 drivers/base/core.c:4160
android_device_create drivers/usb/gadget/configfs.c:1788 [inline]
gadgets_make+0x816/0xa70 drivers/usb/gadget/configfs.c:1885
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_mkdir fs/namei.c:4118 [inline]
__se_sys_mkdir fs/namei.c:4116 [inline]
__x64_sys_mkdir+0x6e/0x80 fs/namei.c:4116
x64_sys_call+0x124/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:84
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 303:
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
device_create_release+0x15/0x20 drivers/base/core.c:4085
device_release+0x96/0x1c0 drivers/base/core.c:-1
kobject_cleanup lib/kobject.c:713 [inline]
kobject_release lib/kobject.c:744 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x18a/0x270 lib/kobject.c:761
put_device drivers/base/core.c:3530 [inline]
device_unregister drivers/base/core.c:3656 [inline]
device_destroy+0xb4/0xf0 drivers/base/core.c:4226
android_device_destroy drivers/usb/gadget/configfs.c:1820 [inline]
gadgets_drop+0xa0/0xd0 drivers/usb/gadget/configfs.c:1901
client_drop_item fs/configfs/dir.c:933 [inline]
configfs_rmdir+0x871/0x960 fs/configfs/dir.c:1536
vfs_rmdir+0x1ae/0x450 fs/namei.c:4157
do_rmdir+0x261/0x6b0 fs/namei.c:4218
__do_sys_rmdir fs/namei.c:4237 [inline]
__se_sys_rmdir fs/namei.c:4235 [inline]
__x64_sys_rmdir+0x49/0x50 fs/namei.c:4235
x64_sys_call+0x25f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:85
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 ffff88810b070800
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 60 bytes inside of
1024-byte region [ffff88810b070800, ffff88810b070c00)
The buggy address belongs to the page:
page:ffffea00042c1c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10b070
head:ffffea00042c1c00 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 0xd2000(__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, ts 2031452132, 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+0x16a/0x2c0 mm/slub.c:4432
__kmalloc_node include/linux/slab.h:487 [inline]
kmalloc_node include/linux/slab.h:642 [inline]
kzalloc_node include/linux/slab.h:761 [inline]
blk_mq_alloc_hctx block/blk-mq.c:2841 [inline]
blk_mq_alloc_and_init_hctx block/blk-mq.c:3255 [inline]
blk_mq_realloc_hw_ctxs+0x40d/0x1660 block/blk-mq.c:3307
blk_mq_init_allocated_queue+0x3ea/0x1770 block/blk-mq.c:3368
blk_mq_init_queue_data block/blk-mq.c:3203 [inline]
blk_mq_init_queue+0x6c/0xd0 block/blk-mq.c:3213
scsi_alloc_sdev+0x66c/0x9c0 drivers/scsi/scsi_scan.c:319
scsi_probe_and_add_lun+0x180/0x35d0 drivers/scsi/scsi_scan.c:1156
__scsi_scan_target+0x1d2/0xb70 drivers/scsi/scsi_scan.c:1637
scsi_scan_channel drivers/scsi/scsi_scan.c:1725 [inline]
scsi_scan_host_selected+0x34e/0x600 drivers/scsi/scsi_scan.c:1754
do_scsi_scan_host drivers/scsi/scsi_scan.c:1893 [inline]
scsi_scan_host+0x39e/0x670 drivers/scsi/scsi_scan.c:1923
page_owner free stack trace missing
Memory state around the buggy address:
ffff88810b070700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88810b070780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88810b070800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88810b070880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88810b070900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 0 PID: 303 at lib/refcount.c:25 refcount_warn_saturate+0x104/0x1a0 lib/refcount.c:25
Modules linked in:
CPU: 0 PID: 303 Comm: syz-executor360 Tainted: G B 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 80 47 63 85 e8 c8 47 5a 02 0f 0b eb df e8 5f 80 19 ff c6 05 1b ea 95 04 01 48 c7 c7 c0 46 63 85 e8 ac 47 5a 02 <0f> 0b eb c3 e8 43 80 19 ff c6 05 00 ea 95 04 01 48 c7 c7 20 47 63
RSP: 0018:ffffc900009979f8 EFLAGS: 00010246
RAX: ec8ae682d7094700 RBX: 0000000000000002 RCX: ffff88811b8862c0
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffc90000997a08 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000132ef0 R12: 1ffff1102160b30e
R13: dffffc0000000000 R14: 0000000000000002 R15: 0000000000000000
FS: 0000555566f423c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f90f3de76e8 CR3: 00000001244c9000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__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: 0033:0x7fbe667cdc79
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd10a8fa78 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 0000200000000100 RCX: 00007fbe667cdc79
RDX: 00000000000001ff RSI: 0000200000000100 RDI: 00000000ffffff9c
RBP: 0032672f74656764 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd10a8fbb8
R13: 0000000000000002 R14: 00007fbe6685eca0 R15: 0000000000000002
</TASK>
---[ end trace e491d44357f168b1 ]---
------------[ cut here ]------------
refcount_t: saturated; leaking memory.
WARNING: CPU: 0 PID: 303 at lib/refcount.c:22 refcount_warn_saturate+0x158/0x1a0 lib/refcount.c:22
Modules linked in:
CPU: 0 PID: 303 Comm: syz-executor360 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 60 46 63 85 e8 74 47 5a 02 0f 0b eb 8b e8 0b 80 19 ff c6 05 c6 e9 95 04 01 48 c7 c7 60 46 63 85 e8 58 47 5a 02 <0f> 0b e9 6c ff ff ff e8 ec 7f 19 ff c6 05 ab e9 95 04 01 48 c7 c7
RSP: 0018:ffffc900009978b8 EFLAGS: 00010246
RAX: ec8ae682d7094700 RBX: 0000000000000001 RCX: ffff88811b8862c0
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffc900009978c8 R08: ffffc90000997327 R09: 1ffff92000132e64
R10: dffffc0000000000 R11: fffff52000132e65 R12: 00000000c0000000
R13: ffff88810b059818 R14: 0000000000000001 R15: ffff88810b070838
FS: 0000555566f423c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f90f3de76e8 CR3: 00000001244c9000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__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
device_add+0x398/0xe90 drivers/base/core.c:3357
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: 0033:0x7fbe667cdc79
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd10a8fa78 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 0000200000000100 RCX: 00007fbe667cdc79
RDX: 00000000000001ff RSI: 0000200000000100 RDI: 00000000ffffff9c
RBP: 0032672f74656764 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd10a8fbb8
R13: 0000000000000002 R14: 00007fbe6685eca0 R15: 0000000000000002
</TASK>
---[ end trace e491d44357f168b2 ]---
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 303 at lib/refcount.c:28 refcount_warn_saturate+0x120/0x1a0 lib/refcount.c:28
Modules linked in:
CPU: 0 PID: 303 Comm: syz-executor360 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 c0 46 63 85 e8 ac 47 5a 02 0f 0b eb c3 e8 43 80 19 ff c6 05 00 ea 95 04 01 48 c7 c7 20 47 63 85 e8 90 47 5a 02 <0f> 0b eb a7 e8 27 80 19 ff c6 05 e1 e9 95 04 01 48 c7 c7 60 46 63
RSP: 0018:ffffc90000997880 EFLAGS: 00010246
RAX: ec8ae682d7094700 RBX: 0000000000000003 RCX: ffff88811b8862c0
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffc90000997890 R08: ffff8881f7032f3f R09: 1ffff1103ee065e7
R10: dffffc0000000000 R11: ffffed103ee065e8 R12: 00000000c0000000
R13: ffff88810b07083c R14: 0000000000000003 R15: ffff88810b070838
FS: 0000555566f423c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f90f3de76e8 CR3: 00000001244c9000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__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
device_add+0x398/0xe90 drivers/base/core.c:3357
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: 0033:0x7fbe667cdc79
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd10a8fa78 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 0000200000000100 RCX: 00007fbe667cdc79
RDX: 00000000000001ff RSI: 0000200000000100 RDI: 00000000ffffff9c
RBP: 0032672f74656764 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd10a8fbb8
---
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