==================================================================
BUG: KASAN: slab-use-after-free in strlen+0x57/0x70 lib/string.c:425
Read of size 1 at addr ffff888025d091e0 by task dhcpcd/5434

CPU: 0 PID: 5434 Comm: dhcpcd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 strlen+0x57/0x70 lib/string.c:425
 nla_put_string+0x19/0x30 include/net/netlink.h:1566
 rtnl_fill_ifinfo+0x1ca8/0x1e50 net/core/rtnetlink.c:1943
 rtnl_dump_ifinfo+0xd09/0x13c0 net/core/rtnetlink.c:2284
 netlink_dump+0x7b1/0xec0 net/netlink/af_netlink.c:2269
 netlink_recvmsg+0x693/0xe60 net/netlink/af_netlink.c:1981
 sock_recvmsg_nosec net/socket.c:1047 [inline]
 sock_recvmsg net/socket.c:1069 [inline]
 ____sys_recvmsg+0x2bd/0x5d0 net/socket.c:2814
 ___sys_recvmsg+0x214/0x590 net/socket.c:2856
 __sys_recvmsg net/socket.c:2886 [inline]
 __do_sys_recvmsg net/socket.c:2896 [inline]
 __se_sys_recvmsg net/socket.c:2893 [inline]
 __x64_sys_recvmsg+0x21e/0x2f0 net/socket.c:2893
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f0d6912d407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffc4e0c2f70 EFLAGS: 00000202 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 00007f0d690a3740 RCX: 00007f0d6912d407
RDX: 0000000000000000 RSI: 00007ffc4e0c3000 RDI: 0000000000000021
RBP: 00007ffc4e0c2fe4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000001dd8
R13: 00007ffc4e0c2ff0 R14: 00007ffc4e0c30e0 R15: 0000000000000000
 </TASK>

Allocated by task 13186:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 ____kasan_kmalloc mm/kasan/common.c:375 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384
 kasan_kmalloc include/linux/kasan.h:198 [inline]
 __do_kmalloc_node mm/slab_common.c:1007 [inline]
 __kmalloc_node_track_caller+0xb4/0x230 mm/slab_common.c:1027
 kvasprintf+0xec/0x1a0 lib/kasprintf.c:25
 kobject_set_name_vargs+0x61/0x110 lib/kobject.c:274
 dev_set_name+0xe3/0x140 drivers/base/core.c:3488
 usb_add_gadget+0x475/0x6f0 drivers/usb/gadget/udc/core.c:1448
 usb_add_gadget_udc_release+0x19c/0x1f0 drivers/usb/gadget/udc/core.c:1506
 dummy_udc_probe+0x68a/0x780 drivers/usb/gadget/udc/dummy_hcd.c:1120
 platform_probe+0x13b/0x1c0 drivers/base/platform.c:1376
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x247/0xae0 drivers/base/dd.c:717
 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:879
 device_driver_attach+0xe0/0x1d0 drivers/base/dd.c:1206
 bind_store+0x1cc/0x210 drivers/base/bus.c:267
 kernfs_fop_write_iter+0x3a4/0x520 fs/kernfs/file.c:352
 call_write_iter include/linux/fs.h:2018 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x474/0x9a0 fs/read_write.c:584
 ksys_write+0x151/0x260 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Freed by task 13242:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x28/0x40 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1811 [inline]
 slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 __kmem_cache_free+0xba/0x1f0 mm/slub.c:3843
 kobject_cleanup lib/kobject.c:695 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x260/0x450 lib/kobject.c:737
 platform_remove+0x6d/0xe0 drivers/base/platform.c:1396
 device_remove drivers/base/dd.c:626 [inline]
 __device_release_driver drivers/base/dd.c:1351 [inline]
 device_release_driver_internal+0x408/0x6f0 drivers/base/dd.c:1374
 unbind_store+0x1a1/0x1d0 drivers/base/bus.c:244
 kernfs_fop_write_iter+0x3a4/0x520 fs/kernfs/file.c:352
 call_write_iter include/linux/fs.h:2018 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x474/0x9a0 fs/read_write.c:584
 ksys_write+0x151/0x260 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff888025d091e0
 which belongs to the cache kmalloc-16 of size 16
The buggy address is located 0 bytes inside of
 freed 16-byte region [ffff888025d091e0, ffff888025d091f0)

The buggy address belongs to the physical page:
page:ffffea0000974240 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888025d09e00 pfn:0x25d09
flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000800 ffff888017c413c0 ffffea0000abbad0 ffffea00009949d0
raw: ffff888025d09e00 0000000000800078 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 5773, tgid 5773 (syz-executor), ts 105581293961, free_ts 105561746386
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1582
 prep_new_page mm/page_alloc.c:1589 [inline]
 get_page_from_freelist+0x2181/0x22a0 mm/page_alloc.c:3221
 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4501
 __alloc_pages_node include/linux/gfp.h:237 [inline]
 alloc_slab_page+0x4f/0x180 mm/slub.c:1883
 allocate_slab mm/slub.c:2028 [inline]
 new_slab+0x87/0x2d0 mm/slub.c:2081
 ___slab_alloc+0xc5c/0x12f0 mm/slub.c:3253
 __slab_alloc mm/slub.c:3339 [inline]
 __slab_alloc_node mm/slub.c:3392 [inline]
 slab_alloc_node mm/slub.c:3485 [inline]
 __kmem_cache_alloc_node+0x11f/0x250 mm/slub.c:3534
 __do_kmalloc_node mm/slab_common.c:1006 [inline]
 __kmalloc_node+0xa6/0x240 mm/slab_common.c:1014
 kmalloc_node include/linux/slab.h:620 [inline]
 kvmalloc_node+0x70/0x180 mm/util.c:617
 xt_jumpstack_alloc net/netfilter/x_tables.c:1377 [inline]
 xt_replace_table+0x185/0x750 net/netfilter/x_tables.c:1416
 __do_replace+0x169/0x9b0 net/ipv6/netfilter/ip6_tables.c:1079
 do_replace net/ipv6/netfilter/ip6_tables.c:1156 [inline]
 do_ip6t_set_ctl+0xb41/0xe10 net/ipv6/netfilter/ip6_tables.c:1641
 nf_setsockopt+0x263/0x280 net/netfilter/nf_sockopt.c:101
 do_sock_setsockopt+0x175/0x1a0 net/socket.c:2322
 __sys_setsockopt net/socket.c:2345 [inline]
 __do_sys_setsockopt net/socket.c:2354 [inline]
 __se_sys_setsockopt net/socket.c:2351 [inline]
 __x64_sys_setsockopt+0x182/0x200 net/socket.c:2351
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1182 [inline]
 free_unref_page_prepare+0x7d7/0x8f0 mm/page_alloc.c:2366
 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2459
 __slab_free+0x35a/0x400 mm/slub.c:3736
 qlink_free mm/kasan/quarantine.c:166 [inline]
 qlist_free_all+0x75/0xd0 mm/kasan/quarantine.c:185
 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6a/0x4d0 mm/slab.h:770
 slab_alloc_node mm/slub.c:3495 [inline]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc+0x17e/0x2c0 mm/slub.c:3519
 kmem_cache_zalloc include/linux/slab.h:711 [inline]
 jbd2_alloc_handle include/linux/jbd2.h:1608 [inline]
 new_handle fs/jbd2/transaction.c:461 [inline]
 jbd2__journal_start+0x140/0x5b0 fs/jbd2/transaction.c:488
 __ext4_journal_start_sb+0x203/0x560 fs/ext4/ext4_jbd2.c:112
 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
 ext4_dirty_inode+0x93/0x110 fs/ext4/inode.c:6141
 __mark_inode_dirty+0x2cc/0xc90 fs/fs-writeback.c:2522
 generic_update_time fs/inode.c:1981 [inline]
 inode_update_time fs/inode.c:1994 [inline]
 __file_update_time fs/inode.c:2180 [inline]
 file_update_time+0x187/0x1a0 fs/inode.c:2210
 ext4_page_mkwrite+0x1f9/0x11a0 fs/ext4/inode.c:6262
 do_page_mkwrite+0x153/0x3f0 mm/memory.c:2951
 wp_page_shared mm/memory.c:3311 [inline]
 do_wp_page+0xd4d/0x34d0 mm/memory.c:3396

Memory state around the buggy address:
 ffff888025d09080: fa fb fc fc fa fb fc fc fa fb fc fc fa fb fc fc
 ffff888025d09100: fa fb fc fc 00 00 fc fc 00 05 fc fc fa fb fc fc
>ffff888025d09180: fa fb fc fc fa fb fc fc fa fb fc fc fa fb fc fc
                                                       ^
 ffff888025d09200: fa fb fc fc fb fb fc fc fa fb fc fc fa fb fc fc
 ffff888025d09280: fa fb fc fc fa fb fc fc fa fb fc fc fa fb fc fc
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