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BUG: KASAN: use-after-free in rose_timer_expiry+0x40c/0x470 net/rose/rose_timer.c:183
Read of size 2 at addr ffff0000cd016c2a by task syz.3.1173/8418

CPU: 1 PID: 8418 Comm: syz.3.1173 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
Call trace:
 dump_backtrace+0x0/0x43c arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106
 print_address_description+0x78/0x30c mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xec/0x15c mm/kasan/report.c:451
 __asan_report_load2_noabort+0x44/0x50 mm/kasan/report_generic.c:307
 rose_timer_expiry+0x40c/0x470 net/rose/rose_timer.c:183
 call_timer_fn+0x19c/0x858 kernel/time/timer.c:1451
 expire_timers kernel/time/timer.c:1496 [inline]
 __run_timers+0x46c/0x6c4 kernel/time/timer.c:1767
 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1780
 handle_softirqs+0x344/0xbf0 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 do_softirq_own_stack include/asm-generic/softirq_stack.h:10 [inline]
 invoke_softirq kernel/softirq.c:457 [inline]
 __irq_exit_rcu+0x240/0x440 kernel/softirq.c:659
 irq_exit+0x14/0x88 kernel/softirq.c:683
 handle_domain_irq+0x14c/0x1fc kernel/irq/irqdesc.c:711
 gic_handle_irq+0x78/0x1c8 drivers/irqchip/irq-gic-v3.c:765
 call_on_irq_stack+0x24/0x30 arch/arm64/kernel/entry.S:855
 do_interrupt_handler+0x6c/0x88 arch/arm64/kernel/entry-common.c:267
 el1_interrupt+0x30/0x58 arch/arm64/kernel/entry-common.c:454
 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:470
 el1h_64_irq+0x78/0x7c arch/arm64/kernel/entry.S:522
 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:122 [inline]
 lock_acquire+0x234/0x620 kernel/locking/lockdep.c:5626
 __might_fault+0xc8/0x128 mm/memory.c:5357
 do_recvmmsg+0x2cc/0x85c net/socket.c:2797
 __sys_recvmmsg net/socket.c:2870 [inline]
 __do_sys_recvmmsg net/socket.c:2893 [inline]
 __se_sys_recvmmsg net/socket.c:2886 [inline]
 __arm64_sys_recvmmsg+0x17c/0x238 net/socket.c:2886
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Allocated by task 8059:
 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_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc+0xb0/0xf0 mm/kasan/common.c:522
 kasan_kmalloc include/linux/kasan.h:264 [inline]
 __kmalloc_node_track_caller+0x234/0x3bc mm/slub.c:4963
 kmalloc_reserve+0xe4/0x26c net/core/skbuff.c:356
 __alloc_skb+0x23c/0x67c net/core/skbuff.c:427
 alloc_skb include/linux/skbuff.h:1162 [inline]
 sock_wmalloc+0xac/0x134 net/core/sock.c:2380
 l2tp_ip_sendmsg+0x1a0/0x1184 net/l2tp/l2tp_ip.c:437
 inet_sendmsg+0x154/0x284 net/ipv4/af_inet.c:834
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x61c/0x920 net/socket.c:2436
 ___sys_sendmsg+0x1d0/0x240 net/socket.c:2490
 __sys_sendmmsg+0x218/0x5f0 net/socket.c:2576
 __do_sys_sendmmsg net/socket.c:2605 [inline]
 __se_sys_sendmmsg net/socket.c:2602 [inline]
 __arm64_sys_sendmmsg+0xa0/0xbc net/socket.c:2602
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Freed by task 8059:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4c/0x84 mm/kasan/common.c:46
 kasan_set_free_info+0x28/0x4c mm/kasan/generic.c:360
 ____kasan_slab_free+0x118/0x164 mm/kasan/common.c:366
 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:374
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1705 [inline]
 slab_free_freelist_hook+0x128/0x1e8 mm/slub.c:1731
 slab_free mm/slub.c:3499 [inline]
 kfree+0x170/0x40c mm/slub.c:4559
 skb_free_head net/core/skbuff.c:655 [inline]
 pskb_expand_head+0x288/0xf94 net/core/skbuff.c:1742
 skb_expand_head+0x1a8/0x3bc net/core/skbuff.c:1867
 ip_finish_output2+0xec0/0x1228 net/ipv4/ip_output.c:209
 __ip_finish_output net/ipv4/ip_output.c:-1 [inline]
 ip_finish_output+0x1b0/0x448 net/ipv4/ip_output.c:316
 NF_HOOK_COND include/linux/netfilter.h:291 [inline]
 ip_output+0x314/0x414 net/ipv4/ip_output.c:430
 dst_output include/net/dst.h:452 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 __ip_queue_xmit+0xe00/0x18f0 net/ipv4/ip_output.c:532
 ip_queue_xmit+0x5c/0x7c net/ipv4/ip_output.c:546
 l2tp_ip_sendmsg+0x4c8/0x1184 net/l2tp/l2tp_ip.c:498
 inet_sendmsg+0x154/0x284 net/ipv4/af_inet.c:834
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x61c/0x920 net/socket.c:2436
 ___sys_sendmsg+0x1d0/0x240 net/socket.c:2490
 __sys_sendmmsg+0x218/0x5f0 net/socket.c:2576
 __do_sys_sendmmsg net/socket.c:2605 [inline]
 __se_sys_sendmmsg net/socket.c:2602 [inline]
 __arm64_sys_sendmmsg+0xa0/0xbc net/socket.c:2602
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

The buggy address belongs to the object at ffff0000cd016c00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 42 bytes inside of
 512-byte region [ffff0000cd016c00, ffff0000cd016e00)
The buggy address belongs to the page:
page:000000006efc063e refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10d014
head:000000006efc063e order:2 compound_mapcount:0 compound_pincount:0
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 dead000000000100 dead000000000122 ffff0000c0002600
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000cd016b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000cd016b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff0000cd016c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff0000cd016c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000cd016d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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