================================================================== BUG: KASAN: use-after-free in tcp_retransmit_timer+0x68d/0x2680 net/ipv4/tcp_timer.c:542 Read of size 8 at addr ffff88802ad1b758 by task kworker/u4:3/373 CPU: 0 PID: 373 Comm: kworker/u4:3 Not tainted 5.15.177-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Workqueue: bat_events batadv_nc_worker 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+0x68d/0x2680 net/ipv4/tcp_timer.c:542 tcp_write_timer_handler+0x1f7/0x970 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:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:202 Code: 1f 84 00 00 00 00 00 0f 1f 00 53 48 89 fb e8 17 00 00 00 48 8b 3d 98 03 8a 0c 48 89 de 5b e9 47 11 49 00 cc cc cc cc cc cc cc <48> 8b 04 24 65 48 8b 0d 24 ea 81 7e 65 8b 15 25 ea 81 7e 81 e2 00 RSP: 0018:ffffc90002f1fbe8 EFLAGS: 00000287 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88801e771dc0 RDX: 0000000000000000 RSI: ffffffff8af9f2a0 RDI: ffffffff8af9f260 RBP: 0000000000000001 R08: ffffffff8a1c2105 R09: fffffbfff2131821 R10: 0000000000000000 R11: dffffc0000000001 R12: 00000000000001b1 R13: dffffc0000000000 R14: ffff888079380c80 R15: ffff888060f1ce80 rcu_lock_release+0x5/0x20 include/linux/rcupdate.h:316 rcu_read_unlock include/linux/rcupdate.h:772 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:416 [inline] batadv_nc_worker+0x239/0x5b0 net/batman-adv/network-coding.c:723 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 Allocated by task 4170: 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: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 154: 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 ffff88802ad1b500 which belongs to the cache net_namespace of size 6528 The buggy address is located 600 bytes inside of 6528-byte region [ffff88802ad1b500, ffff88802ad1ce80) The buggy address belongs to the page: page:ffffea0000ab4600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2ad18 head:ffffea0000ab4600 order:3 compound_mapcount:0 compound_pincount:0 memcg:ffff888028431d01 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 0000000100000001 ffff8880175ea3c0 raw: 0000000000000000 0000000000040004 00000001ffffffff ffff888028431d01 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 4171, ts 59916535178, free_ts 59865675561 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:5465 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: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 getname_flags+0xb8/0x4e0 fs/namei.c:138 do_sys_openat2+0xd2/0x4f0 fs/open.c:1247 do_sys_open fs/open.c:1269 [inline] __do_sys_openat fs/open.c:1285 [inline] __se_sys_openat fs/open.c:1280 [inline] __x64_sys_openat+0x243/0x290 fs/open.c:1280 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 Memory state around the buggy address: ffff88802ad1b600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802ad1b680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88802ad1b700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802ad1b780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802ad1b800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 84 00 test %al,(%rax) 2: 00 00 add %al,(%rax) 4: 00 00 add %al,(%rax) 6: 0f 1f 00 nopl (%rax) 9: 53 push %rbx a: 48 89 fb mov %rdi,%rbx d: e8 17 00 00 00 call 0x29 12: 48 8b 3d 98 03 8a 0c mov 0xc8a0398(%rip),%rdi # 0xc8a03b1 19: 48 89 de mov %rbx,%rsi 1c: 5b pop %rbx 1d: e9 47 11 49 00 jmp 0x491169 22: cc int3 23: cc int3 24: cc int3 25: cc int3 26: cc int3 27: cc int3 28: cc int3 * 29: 48 8b 04 24 mov (%rsp),%rax <-- trapping instruction 2d: 65 48 8b 0d 24 ea 81 mov %gs:0x7e81ea24(%rip),%rcx # 0x7e81ea59 34: 7e 35: 65 8b 15 25 ea 81 7e mov %gs:0x7e81ea25(%rip),%edx # 0x7e81ea61 3c: 81 .byte 0x81 3d: e2 00 loop 0x3f