================================================================== BUG: KASAN: use-after-free in tcp_probe_timer net/ipv4/tcp_timer.c:388 [inline] BUG: KASAN: use-after-free in tcp_write_timer_handler+0x7ef/0x930 net/ipv4/tcp_timer.c:652 Read of size 1 at addr ffff8880941b8745 by task syz-executor.2/28436 CPU: 0 PID: 28436 Comm: syz-executor.2 Not tainted 6.1.81-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 print_address_description mm/kasan/report.c:284 [inline] print_report+0x15f/0x4f0 mm/kasan/report.c:395 kasan_report+0x136/0x160 mm/kasan/report.c:495 tcp_probe_timer net/ipv4/tcp_timer.c:388 [inline] tcp_write_timer_handler+0x7ef/0x930 net/ipv4/tcp_timer.c:652 tcp_write_timer+0x12e/0x280 net/ipv4/tcp_timer.c:665 call_timer_fn+0x1ad/0x6b0 kernel/time/timer.c:1474 expire_timers kernel/time/timer.c:1519 [inline] __run_timers+0x67c/0x890 kernel/time/timer.c:1790 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1803 __do_softirq+0x2e9/0xa4c kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x155/0x240 kernel/softirq.c:650 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662 sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:653 RIP: 0010:rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline] RIP: 0010:rcu_is_watching+0x11/0xb0 kernel/rcu/tree.c:721 Code: 48 c7 c7 a0 11 13 8d 4c 89 f6 e8 8a a9 ef 02 e9 2b ff ff ff e8 20 40 16 09 41 57 41 56 53 65 ff 05 3c 37 8f 7e e8 4f 58 16 09 <89> c3 83 f8 08 73 76 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd 50 RSP: 0018:ffffc900034de740 EFLAGS: 00000286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff816a73d7 RDX: 0000000000000000 RSI: ffffffff8b3d2a20 RDI: ffffffff8b3d29e0 RBP: ffffc900034de898 R08: dffffc0000000000 R09: fffffbfff1ce6bf6 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff9200069bcf8 R13: ffffffff81e9a364 R14: ffffffff81e9a364 R15: dffffc0000000000 trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0xd6/0xa20 kernel/locking/lockdep.c:5673 rcu_lock_release include/linux/rcupdate.h:324 [inline] rcu_read_unlock include/linux/rcupdate.h:793 [inline] percpu_ref_tryget_many include/linux/percpu-refcount.h:250 [inline] percpu_ref_tryget+0xfc/0x170 include/linux/percpu-refcount.h:266 css_tryget include/linux/cgroup.h:357 [inline] get_mem_cgroup_from_objcg+0xc8/0x150 include/linux/memcontrol.h:523 obj_cgroup_charge_pages mm/memcontrol.c:3094 [inline] obj_cgroup_charge+0x374/0x630 mm/memcontrol.c:3387 memcg_slab_pre_alloc_hook mm/slab.h:501 [inline] slab_pre_alloc_hook+0x2dd/0x300 mm/slab.h:715 slab_alloc_node mm/slub.c:3318 [inline] slab_alloc mm/slub.c:3406 [inline] __kmem_cache_alloc_lru mm/slub.c:3413 [inline] kmem_cache_alloc+0x4e/0x2d0 mm/slub.c:3422 kmem_cache_zalloc include/linux/slab.h:682 [inline] alloc_buffer_head+0x20/0xf0 fs/buffer.c:2899 alloc_page_buffers+0x329/0x940 fs/buffer.c:829 create_empty_buffers+0x3a/0x7d0 fs/buffer.c:1543 ext4_block_write_begin+0x33b/0x1400 fs/ext4/inode.c:1082 ext4_da_write_begin+0x5ac/0x9c0 fs/ext4/inode.c:3012 generic_perform_write+0x2fc/0x5e0 mm/filemap.c:3817 ext4_buffered_write_iter+0x122/0x3a0 fs/ext4/file.c:285 ext4_file_write_iter+0x1d2/0x1880 __kernel_write_iter+0x2ff/0x710 fs/read_write.c:517 dump_emit_page fs/coredump.c:881 [inline] dump_user_range+0x43d/0x8e0 fs/coredump.c:908 elf_core_dump+0x3d2b/0x4590 fs/binfmt_elf.c:2312 do_coredump+0x18b7/0x2700 fs/coredump.c:755 get_signal+0x1454/0x17d0 kernel/signal.c:2848 arch_do_signal_or_restart+0xb0/0x1a10 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:168 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:204 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:310 exc_page_fault+0x1c0/0x660 arch/x86/mm/fault.c:1530 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570 RIP: 0033:0x3 Code: Unable to access opcode bytes at 0xffffffffffffffd9. RSP: 002b:0000000020000008 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007f81215abf80 RCX: 00007f812147dda9 RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000000 RBP: 00007f81214ca47a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f81215abf80 R15: 00007ffca92e7408 Allocated by task 13335: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 __kasan_slab_alloc+0x65/0x70 mm/kasan/common.c:328 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x52/0x3a0 mm/slab.h:737 slab_alloc_node mm/slub.c:3398 [inline] slab_alloc mm/slub.c:3406 [inline] __kmem_cache_alloc_lru mm/slub.c:3413 [inline] kmem_cache_alloc+0x10c/0x2d0 mm/slub.c:3422 kmem_cache_zalloc include/linux/slab.h:682 [inline] net_alloc net/core/net_namespace.c:410 [inline] copy_net_ns+0x143/0x5d0 net/core/net_namespace.c:465 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:3203 __do_sys_unshare kernel/fork.c:3274 [inline] __se_sys_unshare kernel/fork.c:3272 [inline] __x64_sys_unshare+0x34/0x40 kernel/fork.c:3272 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd Last potentially related work creation: kasan_save_stack+0x3b/0x60 mm/kasan/common.c:45 __kasan_record_aux_stack+0xb0/0xc0 mm/kasan/generic.c:486 insert_work+0x54/0x3d0 kernel/workqueue.c:1361 __queue_work+0xb4b/0xf90 kernel/workqueue.c:1520 call_timer_fn+0x1ad/0x6b0 kernel/time/timer.c:1474 expire_timers kernel/time/timer.c:1514 [inline] __run_timers+0x6a8/0x890 kernel/time/timer.c:1790 __do_softirq+0x2e9/0xa4c kernel/softirq.c:571 Second to last potentially related work creation: kasan_save_stack+0x3b/0x60 mm/kasan/common.c:45 __kasan_record_aux_stack+0xb0/0xc0 mm/kasan/generic.c:486 insert_work+0x54/0x3d0 kernel/workqueue.c:1361 __queue_work+0xb4b/0xf90 kernel/workqueue.c:1520 call_timer_fn+0x1ad/0x6b0 kernel/time/timer.c:1474 expire_timers kernel/time/timer.c:1514 [inline] __run_timers+0x6a8/0x890 kernel/time/timer.c:1790 __do_softirq+0x2e9/0xa4c kernel/softirq.c:571 The buggy address belongs to the object at ffff8880941b8000 which belongs to the cache net_namespace of size 6976 The buggy address is located 1861 bytes inside of 6976-byte region [ffff8880941b8000, ffff8880941b9b40) The buggy address belongs to the physical page: page:ffffea0002506e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880941b8000 pfn:0x941b8 head:ffffea0002506e00 order:3 compound_mapcount:0 compound_pincount:0 memcg:ffff888097a75841 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888140009500 raw: ffff8880941b8000 0000000080040002 00000001ffffffff ffff888097a75841 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 9824, tgid 9823 (syz-executor.2), ts 338453660163, free_ts 338420068857 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2513 prep_new_page mm/page_alloc.c:2520 [inline] get_page_from_freelist+0x31a1/0x3320 mm/page_alloc.c:4279 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5545 alloc_slab_page+0x6a/0x150 mm/slub.c:1794 allocate_slab mm/slub.c:1939 [inline] new_slab+0x84/0x2d0 mm/slub.c:1992 ___slab_alloc+0xc20/0x1270 mm/slub.c:3180 __slab_alloc mm/slub.c:3279 [inline] slab_alloc_node mm/slub.c:3364 [inline] slab_alloc mm/slub.c:3406 [inline] __kmem_cache_alloc_lru mm/slub.c:3413 [inline] kmem_cache_alloc+0x1a5/0x2d0 mm/slub.c:3422 kmem_cache_zalloc include/linux/slab.h:682 [inline] net_alloc net/core/net_namespace.c:410 [inline] copy_net_ns+0x143/0x5d0 net/core/net_namespace.c:465 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:3203 __do_sys_unshare kernel/fork.c:3274 [inline] __se_sys_unshare kernel/fork.c:3272 [inline] __x64_sys_unshare+0x34/0x40 kernel/fork.c:3272 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1440 [inline] free_pcp_prepare mm/page_alloc.c:1490 [inline] free_unref_page_prepare+0xf63/0x1120 mm/page_alloc.c:3358 free_unref_page+0x33/0x3e0 mm/page_alloc.c:3453 free_slab mm/slub.c:2031 [inline] discard_slab mm/slub.c:2037 [inline] __unfreeze_partials+0x1b7/0x210 mm/slub.c:2586 put_cpu_partial+0x17b/0x250 mm/slub.c:2662 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x156/0x170 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x1f/0x70 mm/kasan/common.c:305 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x52/0x3a0 mm/slab.h:737 slab_alloc_node mm/slub.c:3398 [inline] __kmem_cache_alloc_node+0x137/0x260 mm/slub.c:3437 __do_kmalloc_node mm/slab_common.c:954 [inline] __kmalloc+0xa1/0x230 mm/slab_common.c:968 kmalloc include/linux/slab.h:561 [inline] kzalloc include/linux/slab.h:692 [inline] lsm_task_alloc security/security.c:617 [inline] security_task_alloc+0x3f/0x120 security/security.c:1690 copy_process+0x181d/0x4060 kernel/fork.c:2249 kernel_clone+0x222/0x920 kernel/fork.c:2682 __do_sys_clone kernel/fork.c:2823 [inline] __se_sys_clone kernel/fork.c:2807 [inline] __x64_sys_clone+0x231/0x280 kernel/fork.c:2807 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd Memory state around the buggy address: ffff8880941b8600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880941b8680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880941b8700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880941b8780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880941b8800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess): 0: 48 c7 c7 a0 11 13 8d mov $0xffffffff8d1311a0,%rdi 7: 4c 89 f6 mov %r14,%rsi a: e8 8a a9 ef 02 call 0x2efa999 f: e9 2b ff ff ff jmp 0xffffff3f 14: e8 20 40 16 09 call 0x9164039 19: 41 57 push %r15 1b: 41 56 push %r14 1d: 53 push %rbx 1e: 65 ff 05 3c 37 8f 7e incl %gs:0x7e8f373c(%rip) # 0x7e8f3761 25: e8 4f 58 16 09 call 0x9165879 * 2a: 89 c3 mov %eax,%ebx <-- trapping instruction 2c: 83 f8 08 cmp $0x8,%eax 2f: 73 76 jae 0xa7 31: 49 bf 00 00 00 00 00 movabs $0xdffffc0000000000,%r15 38: fc ff df 3b: 4c rex.WR 3c: 8d .byte 0x8d 3d: 34 dd xor $0xdd,%al 3f: 50 push %rax