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BUG: KASAN: use-after-free in tcp_retransmit_timer+0x59c/0x1da8 net/ipv4/tcp_timer.c:535
Read of size 8 at addr ffff00015ac6d780 by task syz-executor.2/9881

CPU: 0 PID: 9881 Comm: syz-executor.2 Not tainted 6.1.82-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:284 [inline]
 print_report+0x174/0x4c0 mm/kasan/report.c:395
 kasan_report+0xd4/0x130 mm/kasan/report.c:495
 __asan_report_load8_noabort+0x2c/0x38 mm/kasan/report_generic.c:351
 tcp_retransmit_timer+0x59c/0x1da8 net/ipv4/tcp_timer.c:535
 tcp_write_timer_handler+0x18c/0x808 net/ipv4/tcp_timer.c:648
 tcp_write_timer+0x170/0x2e4 net/ipv4/tcp_timer.c:665
 call_timer_fn+0x1c0/0xa1c kernel/time/timer.c:1474
 expire_timers kernel/time/timer.c:1519 [inline]
 __run_timers+0x554/0x718 kernel/time/timer.c:1790
 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1803
 __do_softirq+0x314/0xe38 kernel/softirq.c:571
 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:80
 call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:893
 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:85
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0x264/0x4d4 kernel/softirq.c:650
 irq_exit_rcu+0x14/0x84 kernel/softirq.c:662
 __el1_irq arch/arm64/kernel/entry-common.c:472 [inline]
 el1_interrupt+0x38/0x68 arch/arm64/kernel/entry-common.c:486
 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:491
 el1h_64_irq+0x64/0x68 arch/arm64/kernel/entry.S:581
 balance_dirty_pages_ratelimited+0x28/0x34 mm/page-writeback.c:1953
 generic_perform_write+0x468/0x55c mm/filemap.c:3851
 __generic_file_write_iter+0x168/0x388 mm/filemap.c:3945
 generic_file_write_iter+0xb8/0x2b4 mm/filemap.c:3977
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x610/0x914 fs/read_write.c:584
 ksys_write+0x15c/0x26c fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __arm64_sys_write+0x7c/0x90 fs/read_write.c:646
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Allocated by task 4275:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:52
 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505
 __kasan_slab_alloc+0x74/0x8c mm/kasan/common.c:328
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x74/0x458 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+0x230/0x37c 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+0x124/0x590 net/core/net_namespace.c:465
 create_new_namespaces+0x344/0x614 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x108/0x158 kernel/nsproxy.c:226
 ksys_unshare+0x45c/0x874 kernel/fork.c:3203
 __do_sys_unshare kernel/fork.c:3274 [inline]
 __se_sys_unshare kernel/fork.c:3272 [inline]
 __arm64_sys_unshare+0x3c/0x50 kernel/fork.c:3272
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the object at ffff00015ac6d4c0
 which belongs to the cache net_namespace of size 6976
The buggy address is located 704 bytes inside of
 6976-byte region [ffff00015ac6d4c0, ffff00015ac6f000)

The buggy address belongs to the physical page:
page:00000000649e6179 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff00015ac6d4c0 pfn:0x19ac68
head:00000000649e6179 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 0000000000000000 dead000000000001 ffff0000c03de180
raw: ffff00015ac6d4c0 0000000080040003 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff00015ac6d680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff00015ac6d700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff00015ac6d780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff00015ac6d800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff00015ac6d880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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