================================================================== BUG: KFENCE: use-after-free read in memcpy_orig+0x16/0x130 arch/x86/lib/memcpy_64.S:61 Use-after-free read at 0xffff88823bffc060 (in kfence-#253): memcpy_orig+0x16/0x130 arch/x86/lib/memcpy_64.S:61 scr_memcpyw include/linux/vt_buffer.h:38 [inline] fbcon_prepare_logo+0x945/0xc50 drivers/video/fbdev/core/fbcon.c:646 fbcon_init+0x10ee/0x1810 drivers/video/fbdev/core/fbcon.c:1179 visual_init+0x320/0x620 drivers/tty/vt/vt.c:1020 do_bind_con_driver.isra.0+0x636/0x9c0 drivers/tty/vt/vt.c:3960 vt_bind drivers/tty/vt/vt.c:4116 [inline] store_bind+0x609/0x730 drivers/tty/vt/vt.c:4188 dev_attr_store+0x58/0x80 drivers/base/core.c:2437 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352 iter_file_splice_write+0x82b/0x10a0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] direct_splice_actor+0x192/0x6c0 fs/splice.c:1161 splice_direct_to_actor+0x345/0xa30 fs/splice.c:1105 do_splice_direct_actor fs/splice.c:1204 [inline] do_splice_direct+0x174/0x240 fs/splice.c:1230 do_sendfile+0xadc/0xe20 fs/read_write.c:1370 __do_sys_sendfile64 fs/read_write.c:1431 [inline] __se_sys_sendfile64 fs/read_write.c:1417 [inline] __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1417 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f kfence-#253: 0xffff88823bffc000-0xffff88823bffcfff, size=4096, cache=kmalloc-4k allocated by task 13 on cpu 1 at 872.819616s (2.089729s ago): kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:608 __alloc_skb+0x186/0x410 net/core/skbuff.c:690 alloc_skb include/linux/skbuff.h:1383 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:818 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:875 [inline] nsim_dev_trap_report_work+0x2af/0xd10 drivers/net/netdevsim/dev.c:921 process_one_work+0x9c2/0x1840 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x5da/0xe40 kernel/workqueue.c:3421 kthread+0x3b3/0x730 kernel/kthread.c:463 ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 freed by task 13 on cpu 1 at 872.819640s (2.089880s ago): skb_kfree_head net/core/skbuff.c:1068 [inline] skb_free_head+0x119/0x220 net/core/skbuff.c:1080 skb_release_data+0x540/0x700 net/core/skbuff.c:1107 skb_release_all net/core/skbuff.c:1182 [inline] __kfree_skb net/core/skbuff.c:1196 [inline] consume_skb net/core/skbuff.c:1429 [inline] consume_skb+0xc4/0x110 net/core/skbuff.c:1423 nsim_dev_trap_report drivers/net/netdevsim/dev.c:891 [inline] nsim_dev_trap_report_work+0x8cf/0xd10 drivers/net/netdevsim/dev.c:921 process_one_work+0x9c2/0x1840 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x5da/0xe40 kernel/workqueue.c:3421 kthread+0x3b3/0x730 kernel/kthread.c:463 ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 CPU: 0 UID: 0 PID: 20366 Comm: syz.0.3149 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 RIP: 0010:memcpy_orig+0x16/0x130 arch/x86/lib/memcpy_64.S:66 Code: 00 00 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 48 89 f8 48 83 fa 20 72 7e 40 38 fe 7c 35 48 83 ea 20 48 83 ea 20 <4c> 8b 06 4c 8b 4e 08 4c 8b 56 10 4c 8b 5e 18 48 8d 76 20 4c 89 07 RSP: 0018:ffffc900040775f0 EFLAGS: 00010206 RAX: ffff88823bffc060 RBX: ffff888028923000 RCX: ffffffff852f90f5 RDX: 00000000000000c0 RSI: ffff88823bffc060 RDI: ffff88823bffc060 RBP: ffff88823bffbfc0 R08: 0000000000000001 R09: ffffed10477ff82b R10: ffff88823bffc15f R11: 0000000000000000 R12: 0000000000000018 R13: ffffffffffffff60 R14: 0000000000000100 R15: ffffed1005124679 FS: 00007f4b808066c0(0000) GS:ffff8881245e2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff88823bffc060 CR3: 000000003e3fc000 CR4: 00000000003526f0 Call Trace: scr_memcpyw include/linux/vt_buffer.h:38 [inline] fbcon_prepare_logo+0x945/0xc50 drivers/video/fbdev/core/fbcon.c:646 fbcon_init+0x10ee/0x1810 drivers/video/fbdev/core/fbcon.c:1179 visual_init+0x320/0x620 drivers/tty/vt/vt.c:1020 do_bind_con_driver.isra.0+0x636/0x9c0 drivers/tty/vt/vt.c:3960 vt_bind drivers/tty/vt/vt.c:4116 [inline] store_bind+0x609/0x730 drivers/tty/vt/vt.c:4188 dev_attr_store+0x58/0x80 drivers/base/core.c:2437 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352 iter_file_splice_write+0x82b/0x10a0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] direct_splice_actor+0x192/0x6c0 fs/splice.c:1161 splice_direct_to_actor+0x345/0xa30 fs/splice.c:1105 do_splice_direct_actor fs/splice.c:1204 [inline] do_splice_direct+0x174/0x240 fs/splice.c:1230 do_sendfile+0xadc/0xe20 fs/read_write.c:1370 __do_sys_sendfile64 fs/read_write.c:1431 [inline] __se_sys_sendfile64 fs/read_write.c:1417 [inline] __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1417 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4b7f99aeb9 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:00007f4b80806028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f4b7fc16180 RCX: 00007f4b7f99aeb9 RDX: 0000000000000000 RSI: 000000000000000c RDI: 0000000000000005 RBP: 00007f4b7fa08c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4b7fc16218 R14: 00007f4b7fc16180 R15: 00007ffdf1108c28 ================================================================== ---------------- Code disassembly (best guess): 0: 00 00 add %al,(%rax) 2: 66 90 xchg %ax,%ax 4: 90 nop 5: 90 nop 6: 90 nop 7: 90 nop 8: 90 nop 9: 90 nop a: 90 nop b: 90 nop c: 90 nop d: 90 nop e: 90 nop f: 90 nop 10: 90 nop 11: 90 nop 12: 90 nop 13: 90 nop 14: 48 89 f8 mov %rdi,%rax 17: 48 83 fa 20 cmp $0x20,%rdx 1b: 72 7e jb 0x9b 1d: 40 38 fe cmp %dil,%sil 20: 7c 35 jl 0x57 22: 48 83 ea 20 sub $0x20,%rdx 26: 48 83 ea 20 sub $0x20,%rdx * 2a: 4c 8b 06 mov (%rsi),%r8 <-- trapping instruction 2d: 4c 8b 4e 08 mov 0x8(%rsi),%r9 31: 4c 8b 56 10 mov 0x10(%rsi),%r10 35: 4c 8b 5e 18 mov 0x18(%rsi),%r11 39: 48 8d 76 20 lea 0x20(%rsi),%rsi 3d: 4c 89 07 mov %r8,(%rdi)