================================================================== BUG: KASAN: use-after-free in string_nocheck lib/vsprintf.c:643 [inline] BUG: KASAN: use-after-free in string+0x39c/0x3d0 lib/vsprintf.c:725 Read of size 1 at addr ffff8880771def8c by task udevd/14094 CPU: 1 PID: 14094 Comm: udevd Not tainted 6.1.0-rc1-next-20221019-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:253 [inline] print_report+0x15e/0x45d mm/kasan/report.c:364 kasan_report+0xbb/0x1f0 mm/kasan/report.c:464 string_nocheck lib/vsprintf.c:643 [inline] string+0x39c/0x3d0 lib/vsprintf.c:725 vsnprintf+0x71b/0x14f0 lib/vsprintf.c:2800 add_uevent_var+0x15d/0x380 lib/kobject_uevent.c:665 dev_uevent+0x18d/0x770 drivers/base/core.c:2421 uevent_show+0x1b8/0x380 drivers/base/core.c:2492 dev_attr_show+0x4b/0x90 drivers/base/core.c:2195 sysfs_kf_seq_show+0x219/0x3d0 fs/sysfs/file.c:59 seq_read_iter+0x4f5/0x1280 fs/seq_file.c:230 kernfs_fop_read_iter+0x542/0x7a0 fs/kernfs/file.c:275 call_read_iter include/linux/fs.h:2185 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x67d/0x930 fs/read_write.c:470 ksys_read+0x127/0x250 fs/read_write.c:613 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f2399f258fe Code: c0 e9 e6 fe ff ff 50 48 8d 3d 0e c7 09 00 e8 c9 cf 01 00 66 0f 1f 84 00 00 00 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 0f 05 <48> 3d 00 f0 ff ff 77 5a c3 66 0f 1f 84 00 00 00 00 00 48 83 ec 28 RSP: 002b:00007fffb60c3118 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00005626db260750 RCX: 00007f2399f258fe RDX: 0000000000001000 RSI: 00005626db233970 RDI: 0000000000000008 RBP: 00007f2399ff2380 R08: 0000000000000008 R09: 00007f2399ff5a60 R10: 0000000000000010 R11: 0000000000000246 R12: 00005626db260750 R13: 0000000000000d68 R14: 00007f2399ff1780 R15: 0000000000000d68 Allocated by task 14090: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:45 __kasan_unpoison_range-0xf/0x10 ____kasan_slab_free-0xf/0x1c0 kmalloc include/linux/slab.h:582 [inline] raw_ioctl_init+0x152/0x820 drivers/usb/gadget/legacy/raw_gadget.c:460 raw_ioctl+0x8ef/0x27c0 drivers/usb/gadget/legacy/raw_gadget.c:1250 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 14100: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:45 __kasan_unpoison_range-0xf/0x10 kasan_save_free_info+0x2a/0x40 mm/kasan/generic.c:511 ____kasan_slab_free mm/kasan/common.c:236 [inline] ____kasan_slab_free+0x160/0x1c0 mm/kasan/common.c:200 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1724 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1750 slab_free mm/slub.c:3666 [inline] __kmem_cache_free+0xab/0x3b0 mm/slub.c:3679 dev_free+0x9a/0x700 drivers/usb/gadget/legacy/raw_gadget.c:210 kref_put include/linux/kref.h:65 [inline] raw_release+0x219/0x290 drivers/usb/gadget/legacy/raw_gadget.c:424 __fput+0x27c/0xa90 fs/file_table.c:320 task_work_run+0x16b/0x270 kernel/task_work.c:179 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xb35/0x29a0 kernel/exit.c:820 do_group_exit+0xd0/0x2a0 kernel/exit.c:950 __do_sys_exit_group kernel/exit.c:961 [inline] __se_sys_exit_group kernel/exit.c:959 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:959 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd The buggy address belongs to the object at ffff8880771def80 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 12 bytes inside of 32-byte region [ffff8880771def80, ffff8880771defa0) The buggy address belongs to the physical page: page:ffffea0001dc7780 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x771de flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffff888011841500 dead000000400040 0000000000000000 raw: 0000000000000000 dead000000000001 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 11644, tgid 11639 (syz-executor.2), ts 1604685639785, free_ts 1604684982328 prep_new_page mm/page_alloc.c:2538 [inline] get_page_from_freelist+0x10b5/0x2d50 mm/page_alloc.c:4287 __alloc_pages+0x1c7/0x5a0 mm/page_alloc.c:5546 __alloc_pages_node include/linux/gfp.h:223 [inline] alloc_slab_page mm/slub.c:1796 [inline] allocate_slab+0x80/0x300 mm/slub.c:1939 new_slab mm/slub.c:1992 [inline] ___slab_alloc+0xa91/0x1400 mm/slub.c:3185 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3284 slab_alloc_node mm/slub.c:3369 [inline] __kmem_cache_alloc_node+0x191/0x3e0 mm/slub.c:3442 __do_kmalloc_node mm/slab_common.c:954 [inline] __kmalloc_node+0x47/0xc0 mm/slab_common.c:962 kmalloc_array_node include/linux/slab.h:695 [inline] kcalloc_node include/linux/slab.h:700 [inline] memcg_alloc_slab_cgroups+0x8b/0x140 mm/memcontrol.c:2885 account_slab mm/slab.h:652 [inline] allocate_slab+0x270/0x300 mm/slub.c:1957 new_slab mm/slub.c:1992 [inline] ___slab_alloc+0xa91/0x1400 mm/slub.c:3185 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3284 slab_alloc_node mm/slub.c:3369 [inline] __kmem_cache_alloc_node+0x191/0x3e0 mm/slub.c:3442 kmalloc_trace+0x22/0x60 mm/slab_common.c:1046 kmalloc include/linux/slab.h:582 [inline] kzalloc include/linux/slab.h:718 [inline] snmp6_alloc_dev net/ipv6/addrconf.c:353 [inline] ipv6_add_dev+0x614/0x1320 net/ipv6/addrconf.c:403 addrconf_notify+0x6f9/0x1c10 net/ipv6/addrconf.c:3528 notifier_call_chain+0xb5/0x200 kernel/notifier.c:87 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1458 [inline] free_pcp_prepare+0x65c/0xd90 mm/page_alloc.c:1508 free_unref_page_prepare mm/page_alloc.c:3386 [inline] free_unref_page+0x19/0x4d0 mm/page_alloc.c:3482 mm_free_pgd kernel/fork.c:737 [inline] __mmdrop+0xd1/0x400 kernel/fork.c:788 mmdrop include/linux/sched/mm.h:50 [inline] __mmput+0x3fd/0x4c0 kernel/fork.c:1199 mmput+0x5c/0x70 kernel/fork.c:1210 exit_mm kernel/exit.c:516 [inline] do_exit+0xa39/0x29a0 kernel/exit.c:807 do_group_exit+0xd0/0x2a0 kernel/exit.c:950 get_signal+0x21a1/0x2430 kernel/signal.c:2858 arch_do_signal_or_restart+0x82/0x2300 arch/x86/kernel/signal.c:869 exit_to_user_mode_loop kernel/entry/common.c:168 [inline] exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:203 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:296 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd Memory state around the buggy address: ffff8880771dee80: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc ffff8880771def00: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc >ffff8880771def80: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ^ ffff8880771df000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880771df080: 00 00 00 00 00 fc fc fc fc fc fc fc fc 00 00 00 ==================================================================