================================================================== BUG: KASAN: slab-use-after-free in string_nocheck lib/vsprintf.c:648 [inline] BUG: KASAN: slab-use-after-free in string+0x471/0x4d0 lib/vsprintf.c:730 Read of size 1 at addr ffff888020eaf758 by task syz.3.5495/17669 CPU: 1 UID: 0 PID: 17669 Comm: syz.3.5495 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2026 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 string_nocheck lib/vsprintf.c:648 [inline] string+0x471/0x4d0 lib/vsprintf.c:730 vsnprintf+0x422/0x1300 lib/vsprintf.c:2949 seq_vprintf fs/seq_file.c:392 [inline] seq_printf+0x1a4/0x250 fs/seq_file.c:407 page_owner t[ 469.555493][T17669] input_devices_seq_show+0x1bf/0x1130 drivers/input/input.c:1178 seq_read_iter+0xbce/0x1270 fs/seq_file.c:273 seq_read+0x344/0x4d0 fs/seq_file.c:163 pde_read fs/proc/inode.c:308 [inline] proc_reg_read+0x240/0x330 fs/proc/inode.c:320 vfs_read+0x1e4/0xb40 fs/read_write.c:572 ksys_read+0x12a/0x250 fs/read_write.c:716 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2f8179e159 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:00007f2f82625028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f2f81a25fa0 RCX: 00007f2f8179e159 RDX: 0000000000002020 RSI: 00002000000028c0 RDI: 0000000000000003 RBP: 00007f2f8183503b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f2f81a26038 R14: 00007f2f81a25fa0 R15: 00007ffcea5d81a8 Allocated by task 5734: 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:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5414 [inline] __kmalloc_node_track_caller_noprof+0x33d/0x870 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] nlmsg_new include/net/netlink.h:1055 [inline] audit_buffer_alloc kernel/audit.c:1846 [inline] audit_log_start+0x350/0x930 kernel/audit.c:1965 common_lsm_audit+0xb2/0x2b0 security/lsm_audit.c:442 slow_avc_audit+0x186/0x210 security/selinux/avc.c:778 audit_inode_permission+0x1ea/0x2a0 security/selinux/hooks.c:3151 selinux_inode_permission+0x7ed/0x1130 security/selinux/hooks.c:3293 security_inode_permission+0xda/0x250 security/security.c:1842 inode_permission+0x36c/0x620 fs/namei.c:661 may_open+0x2b8/0x480 fs/namei.c:4269 do_open fs/namei.c:4835 [inline] path_openat+0x51f/0x2440 fs/namei.c:5000 do_file_open+0x20e/0x430 fs/namei.c:5029 do_sys_openat2+0x10f/0x1e0 fs/open.c:1417 do_sys_open fs/open.c:1423 [inline] __do_sys_openat fs/open.c:1439 [inline] __se_sys_openat fs/open.c:1434 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1434 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 30: 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:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6508 [inline] kfree+0x22b/0x6d0 mm/slub.c:6801 skb_kfree_head net/core/skbuff.c:1083 [inline] skb_free_head+0xb9/0x160 net/core/skbuff.c:1095 skb_release_data+0x6c5/0x8e0 net/core/skbuff.c:1122 skb_release_all net/core/skbuff.c:1197 [inline] __kfree_skb net/core/skbuff.c:1211 [inline] sk_skb_reason_drop+0x102/0x1b0 net/core/skbuff.c:1250 kfree_skb_reason include/linux/skbuff.h:1323 [inline] kfree_skb include/linux/skbuff.h:1332 [inline] kauditd_hold_skb+0x144/0x210 kernel/audit.c:653 kauditd_send_queue+0x232/0x2e0 kernel/audit.c:808 kauditd_thread+0x645/0xb30 kernel/audit.c:932 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff888020eaf000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1880 bytes inside of freed 2048-byte region [ffff888020eaf000, ffff888020eaf800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x20ea8 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801c034000 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801c034000 dead000000000100 dead000000000122 head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 00fff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5734, tgid 5734 (syz-executor), ts 75567722679 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+0x110d/0x35d0 mm/page_alloc.c:3943 __alloc_frozen_pages_noprof+0x2eb/0x3300 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:7417 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_node_track_caller_noprof+0x6a8/0x870 mm/slub.c:5545 kmalloc_reserve+0xe8/0x350 net/core/skbuff.c:637 pskb_expand_head+0x249/0x10e0 net/core/skbuff.c:2315 netlink_trim+0x22d/0x2f0 net/netlink/af_netlink.c:1300 netlink_broadcast_filtered+0x6d/0xf20 net/netlink/af_netlink.c:1518 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline] nlmsg_multicast include/net/netlink.h:1184 [inline] nlmsg_notify+0xb1/0x290 net/netlink/af_netlink.c:2599 rtnl_notify net/core/rtnetlink.c:994 [inline] rtmsg_ifinfo_send net/core/rtnetlink.c:4614 [inline] rtmsg_ifinfo_event net/core/rtnetlink.c:4630 [inline] rtmsg_ifinfo_event net/core/rtnetlink.c:4617 [inline] rtmsg_ifinfo+0x177/0x1b0 net/core/rtnetlink.c:4636 __dev_notify_flags+0x362/0x4b0 net/core/dev.c:9849 netif_change_flags+0x108/0x160 net/core/dev.c:9882 do_setlink.isra.0+0x1ac4/0x3e60 net/core/rtnetlink.c:3271 page last free pid 6020 tgid 6020 ts 75564937813 stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0x79f/0x10f0 mm/page_alloc.c:2962 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] kmem_cache_alloc_noprof+0x269/0x6a0 mm/slub.c:5010 alloc_filename fs/namei.c:147 [inline] do_getname+0x35/0x390 fs/namei.c:187 getname_flags fs/namei.c:230 [inline] getname include/linux/fs.h:2557 [inline] class_filename_constructor include/linux/fs.h:2584 [inline] __do_sys_symlinkat fs/namei.c:5837 [inline] __se_sys_symlinkat fs/namei.c:5834 [inline] __x64_sys_symlinkat+0x7c/0xe0 fs/namei.c:5834 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888020eaf600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888020eaf680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888020eaf700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888020eaf780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888020eaf800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================