================================================================== BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:112 [inline] BUG: KASAN: slab-use-after-free in atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:252 [inline] BUG: KASAN: slab-use-after-free in __refcount_add include/linux/refcount.h:283 [inline] BUG: KASAN: slab-use-after-free in __refcount_inc include/linux/refcount.h:366 [inline] BUG: KASAN: slab-use-after-free in refcount_inc include/linux/refcount.h:383 [inline] BUG: KASAN: slab-use-after-free in kref_get include/linux/kref.h:45 [inline] BUG: KASAN: slab-use-after-free in config_item_get+0x26/0x90 fs/configfs/item.c:104 Write of size 4 at addr ffff8880426a701c by task syz.2.692/6683 CPU: 1 UI[ 140.029301][ T6683] CPU: 1 UID: 0 PID: 6683 Comm: syz.2.692 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200 instrument_atomic_read_write include/linux/instrumented.h:112 [inline] atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:252 [inline] __refcount_add include/linux/refcount.h:283 [inline] __refcount_inc include/linux/refcount.h:366 [inline] refcount_inc include/linux/refcount.h:383 [inline] kref_get include/linux/kref.h:45 [inline] config_item_get+0x26/0x90 fs/configfs/item.c:104 configfs_get_config_item fs/configfs/configfs_internal.h:127 [inline] get_target fs/configfs/symlink.c:128 [inline] configfs_symlink+0x4ab/0x1030 fs/configfs/symlink.c:185 vfs_symlink+0x18b/0x330 fs/namei.c:5660 filename_symlinkat+0x1cd/0x420 fs/namei.c:5685 __do_sys_symlinkat fs/namei.c:5705 [inline] __se_sys_symlinkat+0x4e/0x2b0 fs/namei.c:5700 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f87d20cde99 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:00007ffe3c3c3e08 EFLAGS: 00000246 ORIG_RAX: 000000000000010a RAX: ffffffffffffffda RBX: 00007f87d2355fa0 RCX: 00007f87d20cde99 RDX: 0000200000000340 RSI: ffffffffffffff9c RDI: 0000200000000300 RBP: 00007f87d2163eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f87d2355fac R14: 00007f87d2355fa0 R15: 00007f87d2355fa0 Allocated by task 6683: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x3d2/0x6b0 mm/slub.c:5489 _kmalloc_noprof include/linux/slab.h:988 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] afunc_alloc_inst+0x4c/0x770 drivers/usb/gadget/function/f_uac2.c:2192 try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline] usb_get_function_instance+0xe3/0x2f0 drivers/usb/gadget/functions.c:44 function_make+0x127/0x360 drivers/usb/gadget/configfs.c:626 configfs_mkdir+0x4f6/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x402/0x620 fs/namei.c:5276 filename_mkdirat+0x289/0x520 fs/namei.c:5309 __do_sys_mkdirat fs/namei.c:5330 [inline] __se_sys_mkdirat+0x35/0x150 fs/namei.c:5327 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6682: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2677 [inline] slab_free mm/slub.c:6377 [inline] kfree+0x1c5/0x6c0 mm/slub.c:6692 usb_put_function_instance+0x90/0xb0 drivers/usb/gadget/functions.c:77 config_item_cleanup fs/configfs/item.c:128 [inline] config_item_release+0x13a/0x2d0 fs/configfs/item.c:137 configfs_rmdir+0x885/0x950 fs/configfs/dir.c:1571 vfs_rmdir+0x3e9/0x6b0 fs/namei.c:5381 filename_rmdir+0x292/0x520 fs/namei.c:5438 __do_sys_unlinkat fs/namei.c:5613 [inline] __se_sys_unlinkat+0x71/0x1a0 fs/namei.c:5606 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8880426a7000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 28 bytes inside of freed 2048-byte region [ffff8880426a7000, ffff8880426a7800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880426a5000 pfn:0x426a0 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x80000000000240(workingset|head|node=0|zone=1) page_type: f5(slab) raw: 0080000000000240 ffff88813ffb2000 ffffea0000f85210 ffffea0000ed2010 raw: ffff8880426a5000 0000000800080007 00000000f5000000 0000000000000000 head: 0080000000000240 ffff88813ffb2000 ffffea0000f85210 ffffea0000ed2010 head: ffff8880426a5000 0000000800080007 00000000f5000000 0000000000000000 head: 0080000000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008 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 5627, tgid 5627 (syz-executor), ts 94010819671, free_ts 71354825921 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859 prep_new_page mm/page_alloc.c:1867 [inline] get_page_from_freelist+0x262a/0x26a0 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304 alloc_slab_page mm/slub.c:3266 [inline] allocate_slab+0x79/0x5e0 mm/slub.c:3380 new_slab mm/slub.c:3426 [inline] refill_objects+0x2d8/0x350 mm/slub.c:7310 refill_sheaf mm/slub.c:2804 [inline] __pcs_replace_empty_main+0x330/0x690 mm/slub.c:4675 alloc_from_pcs mm/slub.c:4773 [inline] slab_alloc_node mm/slub.c:4905 [inline] __do_kmalloc_node mm/slub.c:5333 [inline] __kmalloc_noprof+0x544/0x780 mm/slub.c:5359 _kmalloc_noprof include/linux/slab.h:992 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] ops_init+0x7b/0x5d0 net/core/net_namespace.c:127 setup_net+0x118/0x350 net/core/net_namespace.c:446 copy_net_ns+0x4f9/0x720 net/core/net_namespace.c:579 create_new_namespaces+0x3f0/0x6b0 kernel/nsproxy.c:132 unshare_nsproxy_namespaces+0x149/0x190 kernel/nsproxy.c:234 ksys_unshare+0x57d/0xa00 kernel/fork.c:3269 __do_sys_unshare kernel/fork.c:3343 [inline] __se_sys_unshare kernel/fork.c:3341 [inline] __x64_sys_unshare+0x38/0x50 kernel/fork.c:3341 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 5447 tgid 5447 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0x10e7/0x11c0 mm/page_alloc.c:2950 __folio_put+0x30f/0x3c0 mm/swap.c:112 pipe_buf_release include/linux/pipe_fs_i.h:273 [inline] pipe_update_tail fs/pipe.c:334 [inline] anon_pipe_read+0x67a/0x10c0 fs/pipe.c:453 new_sync_read fs/read_write.c:493 [inline] vfs_read+0x59e/0xa90 fs/read_write.c:574 ksys_read+0x156/0x270 fs/read_write.c:716 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff8880426a6f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880426a6f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880426a7000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880426a7080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880426a7100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================