================================================================== BUG: KASAN: use-after-free in tw_timer_handler+0x8f/0xf0 include/net/net_namespace.h:-1 Read of size 8 at addr ffff888125393b50 by task syz.1.6144/21791 CPU: 0 PID: 21791 Comm: syz.1.6144 Tainted: G W 5.10.238-syzkaller-00282-gd76d4cd0623a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: __dump_stack+0x21/0x24 lib/dump_stack.c:77 dump_stack_lvl+0x169/0x1d8 lib/dump_stack.c:118 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:435 [inline] kasan_report+0xe2/0x130 mm/kasan/report.c:452 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:309 tw_timer_handler+0x8f/0xf0 include/net/net_namespace.h:-1 call_timer_fn+0x38/0x290 kernel/time/timer.c:1450 expire_timers kernel/time/timer.c:1495 [inline] __run_timers+0x639/0x9a0 kernel/time/timer.c:1789 run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1802 __do_softirq+0x255/0x563 kernel/softirq.c:309 asm_call_irq_on_stack+0xf/0x20 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline] do_softirq_own_stack+0x60/0x80 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:405 [inline] __irq_exit_rcu+0x128/0x150 kernel/softirq.c:435 irq_exit_rcu+0x9/0x10 kernel/softirq.c:447 sysvec_apic_timer_interrupt+0xbf/0xe0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:635 RIP: 0010:sock_recvmsg_nosec net/socket.c:-1 [inline] RIP: 0010:____sys_recvmsg+0x46f/0x580 net/socket.c:2593 Code: 5d c3 e8 94 27 d6 fd 4d 8d 7e 20 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 4c 89 ff e8 d1 17 10 fe <41> bc 90 00 00 00 4d 03 27 4c 89 e0 48 c1 e8 03 48 b9 00 00 00 00 RSP: 0018:ffffc90000f7f920 EFLAGS: 00000246 RAX: 1ffff11025c47a5c RBX: ffffc90000f7fd60 RCX: dffffc0000000000 RDX: ffffc9000bc42000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc90000f7fab0 R08: dffffc0000000000 R09: ffffc90000f7f9c0 R10: fffff520001eff48 R11: 1ffff920001eff38 R12: 000000000000bf11 R13: 0000000000000002 R14: ffff88812e23d2c0 R15: ffff88812e23d2e0 ___sys_recvmsg+0x1af/0x4f0 net/socket.c:2637 do_recvmmsg+0x347/0x790 net/socket.c:2731 __sys_recvmmsg net/socket.c:2810 [inline] __do_sys_recvmmsg net/socket.c:2833 [inline] __se_sys_recvmmsg net/socket.c:2826 [inline] __x64_sys_recvmmsg+0x18d/0x240 net/socket.c:2826 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f3d37e3e929 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:00007f3d36486038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f3d38066080 RCX: 00007f3d37e3e929 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003 RBP: 00007f3d37ec0b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f3d38066080 R15: 00007fff69425488 Allocated by task 11250: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:430 [inline] __kasan_slab_alloc+0xbd/0xf0 mm/kasan/common.c:463 kasan_slab_alloc include/linux/kasan.h:244 [inline] slab_post_alloc_hook+0x5d/0x2f0 mm/slab.h:583 slab_alloc_node mm/slub.c:2947 [inline] slab_alloc mm/slub.c:2955 [inline] kmem_cache_alloc+0x165/0x2e0 mm/slub.c:2960 kmem_cache_zalloc include/linux/slab.h:654 [inline] net_alloc net/core/net_namespace.c:421 [inline] copy_net_ns+0x13f/0x520 net/core/net_namespace.c:473 create_new_namespaces+0x3a2/0x650 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x120/0x170 kernel/nsproxy.c:231 ksys_unshare+0x4ac/0x7d0 kernel/fork.c:3156 __do_sys_unshare kernel/fork.c:3224 [inline] __se_sys_unshare kernel/fork.c:3222 [inline] __x64_sys_unshare+0x38/0x40 kernel/fork.c:3222 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb Freed by task 15509: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4a/0x70 mm/kasan/common.c:45 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:362 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370 kasan_slab_free include/linux/kasan.h:220 [inline] slab_free_hook mm/slub.c:1595 [inline] slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1621 slab_free mm/slub.c:3203 [inline] kmem_cache_free+0x100/0x2d0 mm/slub.c:3219 net_free net/core/net_namespace.c:449 [inline] net_drop_ns net/core/net_namespace.c:456 [inline] cleanup_net+0xae3/0xb70 net/core/net_namespace.c:630 process_one_work+0x6e1/0xba0 kernel/workqueue.c:2301 worker_thread+0xa6a/0x13b0 kernel/workqueue.c:2447 kthread+0x346/0x3d0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 The buggy address belongs to the object at ffff8881253939c0 which belongs to the cache net_namespace of size 4672 The buggy address is located 400 bytes inside of 4672-byte region [ffff8881253939c0, ffff888125394c00) The buggy address belongs to the page: page:ffffea000494e400 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888125391340 pfn:0x125390 head:ffffea000494e400 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head) raw: 4000000000010200 ffffea0004680e00 0000000300000003 ffff888107fdd080 raw: ffff888125391340 0000000080060002 00000001ffffffff 0000000000000000 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 276, ts 22231391795, free_ts 22231046553 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2456 [inline] prep_new_page+0x179/0x180 mm/page_alloc.c:2462 get_page_from_freelist+0x2235/0x23d0 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x268/0x5f0 mm/page_alloc.c:5357 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1808 [inline] new_slab+0x84/0x3f0 mm/slub.c:1869 new_slab_objects mm/slub.c:2627 [inline] ___slab_alloc+0x2a6/0x450 mm/slub.c:2791 __slab_alloc+0x63/0xa0 mm/slub.c:2831 slab_alloc_node mm/slub.c:2913 [inline] slab_alloc mm/slub.c:2955 [inline] kmem_cache_alloc+0x1af/0x2e0 mm/slub.c:2960 kmem_cache_zalloc include/linux/slab.h:654 [inline] net_alloc net/core/net_namespace.c:421 [inline] copy_net_ns+0x13f/0x520 net/core/net_namespace.c:473 create_new_namespaces+0x3a2/0x650 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x120/0x170 kernel/nsproxy.c:231 ksys_unshare+0x4ac/0x7d0 kernel/fork.c:3156 __do_sys_unshare kernel/fork.c:3224 [inline] __se_sys_unshare kernel/fork.c:3222 [inline] __x64_sys_unshare+0x38/0x40 kernel/fork.c:3222 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb page last free stack trace: reset_page_owner include/linux/page_owner.h:28 [inline] free_pages_prepare mm/page_alloc.c:1349 [inline] __free_pages_ok+0x7fc/0x820 mm/page_alloc.c:1629 free_the_page mm/page_alloc.c:5418 [inline] __free_pages+0xdd/0x380 mm/page_alloc.c:5427 free_pages+0x82/0x90 mm/page_alloc.c:5438 __stack_depot_save+0x48b/0x4c0 lib/stackdepot.c:359 stack_depot_save+0xe/0x10 lib/stackdepot.c:384 save_stack+0x141/0x1f0 mm/page_owner.c:159 __set_page_owner+0x3b/0x2a0 mm/page_owner.c:219 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2456 [inline] prep_new_page+0x179/0x180 mm/page_alloc.c:2462 get_page_from_freelist+0x2235/0x23d0 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x268/0x5f0 mm/page_alloc.c:5357 __alloc_pages include/linux/gfp.h:544 [inline] __alloc_pages_node include/linux/gfp.h:557 [inline] alloc_pages_node include/linux/gfp.h:571 [inline] alloc_pages include/linux/gfp.h:590 [inline] __stack_depot_save+0x3bb/0x4c0 lib/stackdepot.c:327 kasan_save_stack mm/kasan/common.c:39 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:430 [inline] __kasan_slab_alloc+0xcf/0xf0 mm/kasan/common.c:463 kasan_slab_alloc include/linux/kasan.h:244 [inline] slab_post_alloc_hook+0x5d/0x2f0 mm/slab.h:583 slab_alloc_node mm/slub.c:2947 [inline] slab_alloc mm/slub.c:2955 [inline] kmem_cache_alloc+0x165/0x2e0 mm/slub.c:2960 kmem_cache_alloc_node include/linux/slab.h:423 [inline] alloc_unbound_pwq kernel/workqueue.c:3850 [inline] apply_wqattrs_prepare+0x8a0/0xf70 kernel/workqueue.c:3995 apply_workqueue_attrs_locked kernel/workqueue.c:4078 [inline] apply_workqueue_attrs+0xd4/0x180 kernel/workqueue.c:4115 Memory state around the buggy address: ffff888125393a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888125393a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888125393b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888125393b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888125393c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess): 0: 5d pop %rbp 1: c3 ret 2: e8 94 27 d6 fd call 0xfdd6279b 7: 4d 8d 7e 20 lea 0x20(%r14),%r15 b: 4c 89 f8 mov %r15,%rax e: 48 c1 e8 03 shr $0x3,%rax 12: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx 19: fc ff df 1c: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) 20: 74 08 je 0x2a 22: 4c 89 ff mov %r15,%rdi 25: e8 d1 17 10 fe call 0xfe1017fb * 2a: 41 bc 90 00 00 00 mov $0x90,%r12d <-- trapping instruction 30: 4d 03 27 add (%r15),%r12 33: 4c 89 e0 mov %r12,%rax 36: 48 c1 e8 03 shr $0x3,%rax 3a: 48 rex.W 3b: b9 00 00 00 00 mov $0x0,%ecx