================================================================== BUG: KASAN: use-after-free in tcp_retransmit_timer+0x6ee/0x2890 net/ipv4/tcp_timer.c:515 Read of size 8 at addr ffff888022f68258 by task kworker/u4:4/1127 CPU: 0 PID: 1127 Comm: kworker/u4:4 Not tainted 5.15.111-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023 Workqueue: netns cleanup_net Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb 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+0x6ee/0x2890 net/ipv4/tcp_timer.c:515 tcp_write_timer_handler+0x1f7/0x9c0 net/ipv4/tcp_timer.c:626 tcp_write_timer+0x12e/0x280 net/ipv4/tcp_timer.c:646 call_timer_fn+0x16d/0x560 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers+0x67c/0x890 kernel/time/timer.c:1737 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1750 __do_softirq+0x3b3/0x93a kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x155/0x240 kernel/softirq.c:636 irq_exit_rcu+0x5/0x20 kernel/softirq.c:648 sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1096 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:29 [inline] RIP: 0010:rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:330 [inline] RIP: 0010:rcu_is_watching+0x56/0xa0 kernel/rcu/tree.c:1122 Code: f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 b0 7e 5e 00 48 c7 c3 48 a6 03 00 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 <84> c0 75 1a 8b 03 65 ff 0d 65 af 97 7e 74 08 24 01 5b 41 5e 41 5f RSP: 0018:ffffc900054a7a40 EFLAGS: 00000a06 RAX: 0000000000000000 RBX: ffff8880b9a3a648 RCX: ffff88801d038000 RDX: ffff88801d038000 RSI: ffffffff8ad85ba0 RDI: ffffffff8ad85b60 RBP: ffffc900054a7b70 R08: ffffffff88bb60f1 R09: fffffbfff1f78e21 R10: 0000000000000000 R11: dffffc0000000001 R12: 000000000007b1a7 R13: 1ffffffff1b775e0 R14: ffffffff8c3487e0 R15: dffffc0000000000 rcu_read_unlock include/linux/rcupdate.h:725 [inline] inet_twsk_purge+0x8fa/0xa20 net/ipv4/inet_timewait_sock.c:299 ops_exit_list net/core/net_namespace.c:174 [inline] cleanup_net+0x763/0xb60 net/core/net_namespace.c:596 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2307 worker_thread+0xaca/0x1280 kernel/workqueue.c:2454 kthread+0x3f6/0x4f0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 Allocated by task 3516: 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:711 [inline] net_alloc net/core/net_namespace.c:405 [inline] copy_net_ns+0x143/0x5d0 net/core/net_namespace.c:460 create_new_namespaces+0x425/0x7a0 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x11e/0x170 kernel/nsproxy.c:226 ksys_unshare+0x580/0xb20 kernel/fork.c:3094 __do_sys_unshare kernel/fork.c:3168 [inline] __se_sys_unshare kernel/fork.c:3166 [inline] __x64_sys_unshare+0x34/0x40 kernel/fork.c:3166 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x61/0xcb The buggy address belongs to the object at ffff888022f68000 which belongs to the cache net_namespace of size 6464 The buggy address is located 600 bytes inside of 6464-byte region [ffff888022f68000, ffff888022f69940) The buggy address belongs to the page: page:ffffea00008bda00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888022f68000 pfn:0x22f68 head:ffffea00008bda00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 0000000100000001 ffff8881400053c0 raw: ffff888022f68000 0000000080040001 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 3516, ts 77953440362, free_ts 77857893772 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x322a/0x33c0 mm/page_alloc.c:4159 __alloc_pages+0x272/0x700 mm/page_alloc.c:5421 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:711 [inline] net_alloc net/core/net_namespace.c:405 [inline] copy_net_ns+0x143/0x5d0 net/core/net_namespace.c:460 create_new_namespaces+0x425/0x7a0 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x11e/0x170 kernel/nsproxy.c:226 ksys_unshare+0x580/0xb20 kernel/fork.c:3094 __do_sys_unshare kernel/fork.c:3168 [inline] __se_sys_unshare kernel/fork.c:3166 [inline] __x64_sys_unshare+0x34/0x40 kernel/fork.c:3166 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x61/0xcb 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_trace+0xfb/0x290 mm/slub.c:3245 kmalloc include/linux/slab.h:591 [inline] kzalloc include/linux/slab.h:721 [inline] kernfs_fop_open+0x3b5/0xbc0 fs/kernfs/file.c:628 do_dentry_open+0x807/0xfb0 fs/open.c:826 do_open fs/namei.c:3538 [inline] path_openat+0x2702/0x2f20 fs/namei.c:3672 do_filp_open+0x21c/0x460 fs/namei.c:3699 do_sys_openat2+0x13b/0x500 fs/open.c:1211 do_sys_open fs/open.c:1227 [inline] __do_sys_openat fs/open.c:1243 [inline] __se_sys_openat fs/open.c:1238 [inline] __x64_sys_openat+0x243/0x290 fs/open.c:1238 Memory state around the buggy address: ffff888022f68100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888022f68180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888022f68200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888022f68280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888022f68300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess): 0: f0 48 c1 e8 03 lock shr $0x3,%rax 5: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) a: 74 08 je 0x14 c: 4c 89 f7 mov %r14,%rdi f: e8 b0 7e 5e 00 callq 0x5e7ec4 14: 48 c7 c3 48 a6 03 00 mov $0x3a648,%rbx 1b: 49 03 1e add (%r14),%rbx 1e: 48 89 d8 mov %rbx,%rax 21: 48 c1 e8 03 shr $0x3,%rax 25: 42 0f b6 04 38 movzbl (%rax,%r15,1),%eax * 2a: 84 c0 test %al,%al <-- trapping instruction 2c: 75 1a jne 0x48 2e: 8b 03 mov (%rbx),%eax 30: 65 ff 0d 65 af 97 7e decl %gs:0x7e97af65(%rip) # 0x7e97af9c 37: 74 08 je 0x41 39: 24 01 and $0x1,%al 3b: 5b pop %rbx 3c: 41 5e pop %r14 3e: 41 5f pop %r15