==================================================================
BUG: KASAN: use-after-free in gphonet_set_gadget drivers/usb/gadget/function/f_phonet.c:720 [inline]
BUG: KASAN: use-after-free in pn_bind+0x100/0x9c0 drivers/usb/gadget/function/f_phonet.c:510
Write of size 8 at addr ffff0000d88f46c0 by task syz.3.238/5221

CPU: 1 PID: 5221 Comm: syz.3.238 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
Call trace:
 dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 print_address_description+0x88/0x218 mm/kasan/report.c:316
 print_report+0x50/0x68 mm/kasan/report.c:420
 kasan_report+0xa8/0xfc mm/kasan/report.c:524
 __asan_report_store8_noabort+0x2c/0x38 mm/kasan/report_generic.c:356
 gphonet_set_gadget drivers/usb/gadget/function/f_phonet.c:720 [inline]
 pn_bind+0x100/0x9c0 drivers/usb/gadget/function/f_phonet.c:510
 usb_add_function+0x234/0x7a8 drivers/usb/gadget/composite.c:337
 configfs_composite_bind+0x7e0/0xce4 drivers/usb/gadget/configfs.c:1409
 gadget_bind_driver+0x26c/0x684 drivers/usb/gadget/udc/core.c:1651
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x3a0/0xac4 drivers/base/dd.c:638
 __driver_probe_device+0x1c8/0x368 drivers/base/dd.c:804
 driver_probe_device+0x78/0x324 drivers/base/dd.c:834
 __driver_attach+0x3bc/0x614 drivers/base/dd.c:1220
 bus_for_each_dev+0x148/0x1d0 drivers/base/bus.c:303
 driver_attach+0x50/0x60 drivers/base/dd.c:1237
 bus_add_driver+0x2c0/0x518 drivers/base/bus.c:620
 driver_register+0x200/0x37c drivers/base/driver.c:246
 usb_gadget_register_driver_owner+0xf0/0x25c drivers/usb/gadget/udc/core.c:1730
 gadget_dev_desc_UDC_store+0x168/0x268 drivers/usb/gadget/configfs.c:290
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x260/0x338 fs/configfs/file.c:229
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x3c8/0x7c8 fs/read_write.c:584
 ksys_write+0x12c/0x228 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __arm64_sys_write+0x7c/0x90 fs/read_write.c:646
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Allocated by task 4869:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505
 ____kasan_kmalloc mm/kasan/common.c:375 [inline]
 __kasan_kmalloc+0xa0/0xb8 mm/kasan/common.c:384
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slab_common.c:936 [inline]
 __kmalloc_node+0xdc/0x184 mm/slab_common.c:943
 kmalloc_node include/linux/slab.h:589 [inline]
 kvmalloc_node+0x88/0x1d4 mm/util.c:581
 kvmalloc include/linux/slab.h:716 [inline]
 seq_buf_alloc fs/seq_file.c:38 [inline]
 seq_read_iter+0x1d8/0xc24 fs/seq_file.c:210
 kernfs_fop_read_iter+0x13c/0x5d8 fs/kernfs/file.c:297
 call_read_iter include/linux/fs.h:2259 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x3cc/0x7b8 fs/read_write.c:470
 ksys_read+0x12c/0x228 fs/read_write.c:613
 __do_sys_read fs/read_write.c:623 [inline]
 __se_sys_read fs/read_write.c:621 [inline]
 __arm64_sys_read+0x7c/0x90 fs/read_write.c:621
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Freed by task 4869:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
 kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:516
 ____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:237
 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:245
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1729 [inline]
 slab_free_freelist_hook+0x16c/0x1e8 mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 __kmem_cache_free+0xbc/0x21c mm/slub.c:3700
 kfree+0xd0/0x1a8 mm/slab_common.c:988
 kvfree+0x40/0x50 mm/util.c:627
 seq_release+0x58/0x7c fs/seq_file.c:355
 kernfs_fop_release+0x134/0x194 fs/kernfs/file.c:826
 __fput+0x1b4/0x7b0 fs/file_table.c:320
 ____fput+0x20/0x30 fs/file_table.c:348
 task_work_run+0x1f4/0x280 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 do_notify_resume+0x20f8/0x2c84 arch/arm64/kernel/signal.c:1151
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
 el0_svc+0x98/0x128 arch/arm64/kernel/entry-common.c:638
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the object at ffff0000d88f4000
 which belongs to the cache kmalloc-cg-4k of size 4096
The buggy address is located 1728 bytes inside of
 4096-byte region [ffff0000d88f4000, ffff0000d88f5000)

The buggy address belongs to the physical page:
page:00000000b60526ee refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1188f0
head:00000000b60526ee order:3 compound_mapcount:0 compound_pincount:0
memcg:ffff0000f5272001
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 dead000000000100 dead000000000122 ffff0000c0003500
raw: 0000000000000000 0000000000040004 00000001ffffffff ffff0000f5272001
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000d88f4580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000d88f4600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff0000d88f4680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff0000d88f4700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000d88f4780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
------------[ cut here ]------------
kernel BUG at net/core/dev.c:10149!
Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 5221 Comm: syz.3.238 Tainted: G    B              syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : register_netdevice+0x1624/0x1650 net/core/dev.c:10149
lr : register_netdevice+0x1624/0x1650 net/core/dev.c:10149
sp : ffff800022007400
x29: ffff8000220074d0 x28: dfff800000000000 x27: ffff0000d2f9a0d8
x26: ffff800022007460 x25: ffff0000d88f4000 x24: ffff700004400e8c
x23: 0000000000000000 x22: dfff800000000000 x21: 1fffe0001b11e8c7
x20: 0000000000000000 x19: ffff0000d88f4000 x18: 1fffe00033e7697e
x17: ffff80001537d000 x16: ffff800011b90080 x15: 0000000040000000
x14: 0000000000000001 x13: 1ffff00002f409bc x12: 0000000000080000
x11: 000000000002d25e x10: ffff80002823a000 x9 : ffff80000ff13b80
x8 : 000000000002d25f x7 : 0000000000000000 x6 : ffff80000ff4a608
x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff80000ff13880
x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
 register_netdevice+0x1624/0x1650 net/core/dev.c:10149
 register_netdev+0x48/0x64 net/core/dev.c:10371
 gphonet_register_netdev drivers/usb/gadget/function/f_phonet.c:727 [inline]
 pn_bind+0x110/0x9c0 drivers/usb/gadget/function/f_phonet.c:511
 usb_add_function+0x234/0x7a8 drivers/usb/gadget/composite.c:337
 configfs_composite_bind+0x7e0/0xce4 drivers/usb/gadget/configfs.c:1409
 gadget_bind_driver+0x26c/0x684 drivers/usb/gadget/udc/core.c:1651
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x3a0/0xac4 drivers/base/dd.c:638
 __driver_probe_device+0x1c8/0x368 drivers/base/dd.c:804
 driver_probe_device+0x78/0x324 drivers/base/dd.c:834
 __driver_attach+0x3bc/0x614 drivers/base/dd.c:1220
 bus_for_each_dev+0x148/0x1d0 drivers/base/bus.c:303
 driver_attach+0x50/0x60 drivers/base/dd.c:1237
 bus_add_driver+0x2c0/0x518 drivers/base/bus.c:620
 driver_register+0x200/0x37c drivers/base/driver.c:246
 usb_gadget_register_driver_owner+0xf0/0x25c drivers/usb/gadget/udc/core.c:1730
 gadget_dev_desc_UDC_store+0x168/0x268 drivers/usb/gadget/configfs.c:290
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x260/0x338 fs/configfs/file.c:229
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x3c8/0x7c8 fs/read_write.c:584
 ksys_write+0x12c/0x228 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __arm64_sys_write+0x7c/0x90 fs/read_write.c:646
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
Code: d4210000 96167c14 d4210000 96167c12 (d4210000) 
---[ end trace 0000000000000000 ]---