================================================================== BUG: KASAN: use-after-free in tcp_retransmit_timer+0x6a1/0x26b0 net/ipv4/tcp_timer.c:542 Read of size 8 at addr ffff88802a3e8258 by task syz.2.2269/13777 CPU: 0 PID: 13777 Comm: syz.2.2269 Not tainted 5.15.180-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106 print_address_description+0x63/0x3b0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0x16b/0x1c0 mm/kasan/report.c:451 tcp_retransmit_timer+0x6a1/0x26b0 net/ipv4/tcp_timer.c:542 tcp_write_timer_handler+0x1f7/0x980 net/ipv4/tcp_timer.c:655 tcp_write_timer+0x12e/0x280 net/ipv4/tcp_timer.c:675 call_timer_fn+0x16d/0x560 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x67c/0x890 kernel/time/timer.c:1767 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780 handle_softirqs+0x3a7/0x930 kernel/softirq.c:558 __do_softirq kernel/softirq.c:592 [inline] invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x157/0x240 kernel/softirq.c:641 irq_exit_rcu+0x5/0x20 kernel/softirq.c:653 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:_copy_from_user+0x2/0x170 lib/usercopy.c:12 Code: c7 e0 bf f9 8a e8 0e 00 38 fd 0f 0b eb 89 89 d9 80 e1 07 80 c1 03 38 c1 7c c2 48 89 df e8 f6 5f b6 fd eb b8 cc cc cc cc 41 57 <41> 56 41 55 41 54 53 49 89 d4 49 89 f7 49 89 fe e8 e9 6b 6c fd 48 RSP: 0018:ffffc90002ecfa70 EFLAGS: 00000202 RAX: ffffc90002ecfae0 RBX: 0000000000000002 RCX: 0000000000000000 RDX: 0000000000000038 RSI: 000020000011bbc0 RDI: ffffc90002ecfae0 RBP: ffffc90002ecfc70 R08: dffffc0000000000 R09: ffffc90002ecfae0 R10: 0000000000000000 R11: dffffc0000000001 R12: ffffc90002ecfbe0 R13: dffffc0000000000 R14: 1ffff920005d9f58 R15: ffffc90002ecfae0 copy_from_user include/linux/uaccess.h:192 [inline] __copy_msghdr_from_user net/socket.c:2318 [inline] copy_msghdr_from_user net/socket.c:2369 [inline] recvmsg_copy_msghdr net/socket.c:2621 [inline] ___sys_recvmsg+0x150/0x690 net/socket.c:2693 do_recvmmsg+0x36f/0x8f0 net/socket.c:2791 __sys_recvmmsg net/socket.c:2870 [inline] __do_sys_recvmmsg net/socket.c:2893 [inline] __se_sys_recvmmsg net/socket.c:2886 [inline] __x64_sys_recvmmsg+0x195/0x240 net/socket.c:2886 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f506f355169 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f506d19c038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f506f57d080 RCX: 00007f506f355169 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000004 RBP: 00007f506f3d7a68 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f506f57d080 R15: 00007fff772e0198 Allocated by task 4169: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] __kasan_slab_alloc+0x8e/0xc0 mm/kasan/common.c:467 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook+0x53/0x380 mm/slab.h:519 slab_alloc_node mm/slub.c:3220 [inline] slab_alloc mm/slub.c:3228 [inline] kmem_cache_alloc+0xf3/0x280 mm/slub.c:3233 kmem_cache_zalloc include/linux/slab.h:725 [inline] net_alloc net/core/net_namespace.c:418 [inline] copy_net_ns+0x140/0x5d0 net/core/net_namespace.c:473 create_new_namespaces+0x425/0x7a0 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x11e/0x170 kernel/nsproxy.c:226 ksys_unshare+0x531/0xa40 kernel/fork.c:3099 __do_sys_unshare kernel/fork.c:3173 [inline] __se_sys_unshare kernel/fork.c:3171 [inline] __x64_sys_unshare+0x34/0x40 kernel/fork.c:3171 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 Freed by task 4291: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x80 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0xd8/0x120 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1705 [inline] slab_free_freelist_hook+0xdd/0x160 mm/slub.c:1731 slab_free mm/slub.c:3499 [inline] kmem_cache_free+0x91/0x1f0 mm/slub.c:3515 net_free net/core/net_namespace.c:447 [inline] cleanup_net+0xbd8/0xc90 net/core/net_namespace.c:639 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 The buggy address belongs to the object at ffff88802a3e8000 which belongs to the cache net_namespace of size 6528 The buggy address is located 600 bytes inside of 6528-byte region [ffff88802a3e8000, ffff88802a3e9980) The buggy address belongs to the page: page:ffffea0000a8fa00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88802a3e9a80 pfn:0x2a3e8 head:ffffea0000a8fa00 order:3 compound_mapcount:0 compound_pincount:0 memcg:ffff888020cefd41 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 0000000100000001 ffff8880175ea3c0 raw: ffff88802a3e9a80 0000000080040003 00000001ffffffff ffff888020cefd41 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 4169, ts 52718786004, free_ts 52681784846 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x3b78/0x3d40 mm/page_alloc.c:4192 __alloc_pages+0x272/0x700 mm/page_alloc.c:5466 alloc_slab_page mm/slub.c:1775 [inline] allocate_slab mm/slub.c:1912 [inline] new_slab+0xbb/0x4b0 mm/slub.c:1975 ___slab_alloc+0x6f6/0xe10 mm/slub.c:3008 __slab_alloc mm/slub.c:3095 [inline] slab_alloc_node mm/slub.c:3186 [inline] slab_alloc mm/slub.c:3228 [inline] kmem_cache_alloc+0x18e/0x280 mm/slub.c:3233 kmem_cache_zalloc include/linux/slab.h:725 [inline] net_alloc net/core/net_namespace.c:418 [inline] copy_net_ns+0x140/0x5d0 net/core/net_namespace.c:473 create_new_namespaces+0x425/0x7a0 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x11e/0x170 kernel/nsproxy.c:226 ksys_unshare+0x531/0xa40 kernel/fork.c:3099 __do_sys_unshare kernel/fork.c:3173 [inline] __se_sys_unshare kernel/fork.c:3171 [inline] __x64_sys_unshare+0x34/0x40 kernel/fork.c:3171 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1340 [inline] free_pcp_prepare mm/page_alloc.c:1391 [inline] free_unref_page_prepare+0xc34/0xcf0 mm/page_alloc.c:3317 free_unref_page+0x95/0x2d0 mm/page_alloc.c:3396 free_slab mm/slub.c:2015 [inline] discard_slab mm/slub.c:2021 [inline] __unfreeze_partials+0x1b7/0x210 mm/slub.c:2507 put_cpu_partial+0x132/0x1a0 mm/slub.c:2587 do_slab_free mm/slub.c:3487 [inline] ___cache_free+0xe3/0x100 mm/slub.c:3506 qlist_free_all+0x36/0x90 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x162/0x180 mm/kasan/quarantine.c:283 __kasan_slab_alloc+0x2f/0xc0 mm/kasan/common.c:444 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook+0x53/0x380 mm/slab.h:519 slab_alloc_node mm/slub.c:3220 [inline] slab_alloc mm/slub.c:3228 [inline] kmem_cache_alloc+0xf3/0x280 mm/slub.c:3233 kmem_cache_zalloc include/linux/slab.h:725 [inline] __kernfs_new_node+0xdb/0x750 fs/kernfs/dir.c:593 kernfs_new_node+0x136/0x230 fs/kernfs/dir.c:669 kernfs_create_link+0xa1/0x1f0 fs/kernfs/symlink.c:39 sysfs_do_create_link_sd+0x85/0x100 fs/sysfs/symlink.c:44 device_add_class_symlinks drivers/base/core.c:3141 [inline] device_add+0x6b5/0xfd0 drivers/base/core.c:3360 hci_conn_add_sysfs+0xe4/0x1f0 net/bluetooth/hci_sysfs.c:46 Memory state around the buggy address: ffff88802a3e8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802a3e8180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88802a3e8200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802a3e8280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802a3e8300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== vkms_vblank_simulate: vblank timer overrun ---------------- Code disassembly (best guess), 2 bytes skipped: 0: bf f9 8a e8 0e mov $0xee88af9,%edi 5: 00 38 add %bh,(%rax) 7: fd std 8: 0f 0b ud2 a: eb 89 jmp 0xffffff95 c: 89 d9 mov %ebx,%ecx e: 80 e1 07 and $0x7,%cl 11: 80 c1 03 add $0x3,%cl 14: 38 c1 cmp %al,%cl 16: 7c c2 jl 0xffffffda 18: 48 89 df mov %rbx,%rdi 1b: e8 f6 5f b6 fd call 0xfdb66016 20: eb b8 jmp 0xffffffda 22: cc int3 23: cc int3 24: cc int3 25: cc int3 26: 41 57 push %r15 * 28: 41 56 push %r14 <-- trapping instruction 2a: 41 55 push %r13 2c: 41 54 push %r12 2e: 53 push %rbx 2f: 49 89 d4 mov %rdx,%r12 32: 49 89 f7 mov %rsi,%r15 35: 49 89 fe mov %rdi,%r14 38: e8 e9 6b 6c fd call 0xfd6c6c26 3d: 48 rex.W