================================================================== BUG: KASAN: slab-use-after-free in strlen+0x85/0xa0 lib/string.c:402 Read of size 1 at addr ffff888117b2ba20 by task syz.4.1786/12690 CPU: 1 UID: 0 PID: 12690 Comm: syz.4.1786 Not tainted syzkaller #0 PREEMPT(lazy) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595 strlen+0x85/0xa0 lib/string.c:402 __fortify_strlen include/linux/fortify-string.h:218 [inline] str_to_user+0x26/0xa0 drivers/input/evdev.c:774 evdev_do_ioctl+0x1333/0x1b40 drivers/input/evdev.c:1177 evdev_ioctl_handler drivers/input/evdev.c:1277 [inline] evdev_ioctl+0x16f/0x1a0 drivers/input/evdev.c:1286 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x119/0x710 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb92bd1e199 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:00007fb92a777028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fb92bfa5fa0 RCX: 00007fb92bd1e199 RDX: 0000200000000540 RSI: 0000000080404507 RDI: 0000000000000003 RBP: 00007fb92bdb50b8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb92bfa6038 R14: 00007fb92bfa5fa0 R15: 00007ffcdeaf8da8 Allocated by task 5248: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:409 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:426 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5414 [inline] __kmalloc_node_track_caller_noprof+0x323/0x820 mm/slub.c:5545 kmalloc_reserve+0xe8/0x350 net/core/skbuff.c:637 __alloc_skb+0x185/0x710 net/core/skbuff.c:715 alloc_skb include/linux/skbuff.h:1384 [inline] netlink_alloc_large_skb+0x69/0x150 net/netlink/af_netlink.c:1204 netlink_sendmsg+0x680/0xda0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:800 [inline] __sock_sendmsg net/socket.c:815 [inline] ____sys_sendmsg+0xa4d/0xbe0 net/socket.c:2713 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2767 __sys_sendmsg+0x160/0x210 net/socket.c:2799 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x119/0x710 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5248: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:264 [inline] __kasan_slab_free+0x43/0x70 mm/kasan/common.c:296 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6509 [inline] kfree+0x20c/0x650 mm/slub.c:6802 skb_kfree_head net/core/skbuff.c:1083 [inline] skb_free_head+0xb9/0x160 net/core/skbuff.c:1095 skb_release_data+0x659/0x860 net/core/skbuff.c:1122 skb_release_all net/core/skbuff.c:1197 [inline] __kfree_skb net/core/skbuff.c:1211 [inline] consume_skb net/core/skbuff.c:1448 [inline] consume_skb+0xc4/0x110 net/core/skbuff.c:1442 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline] netlink_unicast+0x58d/0x850 net/netlink/af_netlink.c:1364 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:800 [inline] __sock_sendmsg net/socket.c:815 [inline] ____sys_sendmsg+0xa4d/0xbe0 net/socket.c:2713 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2767 __sys_sendmsg+0x160/0x210 net/socket.c:2799 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x119/0x710 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888117b2b800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 544 bytes inside of freed 1024-byte region [ffff888117b2b800, ffff888117b2bc00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888117b2e000 pfn:0x117b28 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x200000000000240(workingset|head|node=0|zone=2) page_type: f5(slab) raw: 0200000000000240 ffff888100041dc0 ffffea00046ae010 ffffea000423ae10 raw: ffff888117b2e000 000000000010000e 00000000f5000000 0000000000000000 head: 0200000000000240 ffff888100041dc0 ffffea00046ae010 ffffea000423ae10 head: ffff888117b2e000 000000000010000e 00000000f5000000 0000000000000000 head: 0200000000000003 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 2857, tgid 2857 (start-stop-daem), ts 19695021369 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871 prep_new_page mm/page_alloc.c:1879 [inline] get_page_from_freelist+0xf4b/0x3440 mm/page_alloc.c:3943 __alloc_frozen_pages_noprof+0x2d7/0x2f70 mm/page_alloc.c:5436 alloc_slab_page mm/slub.c:3347 [inline] allocate_slab mm/slub.c:3462 [inline] new_slab+0xa9/0x6e0 mm/slub.c:3513 refill_objects+0xe3/0x410 mm/slub.c:7418 refill_sheaf mm/slub.c:2885 [inline] __pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4774 alloc_from_pcs mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:4984 [inline] __do_kmalloc_node mm/slub.c:5413 [inline] __kmalloc_noprof+0x61c/0x7e0 mm/slub.c:5439 _kmalloc_noprof include/linux/slab.h:995 [inline] load_elf_phdrs+0x102/0x210 fs/binfmt_elf.c:537 load_elf_binary+0x298/0x50a0 fs/binfmt_elf.c:866 search_binary_handler fs/exec.c:1779 [inline] exec_binprm fs/exec.c:1811 [inline] bprm_execve fs/exec.c:1867 [inline] bprm_execve+0x8cb/0x17e0 fs/exec.c:1843 do_execveat_common.isra.0+0x4a5/0x580 fs/exec.c:1965 __do_sys_execve fs/exec.c:2038 [inline] __se_sys_execve fs/exec.c:2032 [inline] __x64_sys_execve+0x93/0xd0 fs/exec.c:2032 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x119/0x710 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f page_owner free stack trace missing Memory state around the buggy address: ffff888117b2b900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888117b2b980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888117b2ba00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888117b2ba80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888117b2bb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================