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BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: slab-use-after-free in atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:400 [inline]
BUG: KASAN: slab-use-after-free in __refcount_sub_and_test include/linux/refcount.h:389 [inline]
BUG: KASAN: slab-use-after-free in __refcount_dec_and_test include/linux/refcount.h:432 [inline]
BUG: KASAN: slab-use-after-free in refcount_dec_and_test include/linux/refcount.h:450 [inline]
BUG: KASAN: slab-use-after-free in skb_unref include/linux/skbuff.h:1245 [inline]
BUG: KASAN: slab-use-after-free in __sk_skb_reason_drop net/core/skbuff.c:1175 [inline]
BUG: KASAN: slab-use-after-free in sk_skb_reason_drop+0x37/0x170 net/core/skbuff.c:1203
Write of size 4 at addr ffff888052e9cea4 by task syz.0.0/5328

CPU: 0 UID: 0 PID: 5328 Comm: syz.0.0 Not tainted 6.16.0-rc1-syzkaller-00004-gaef17cb3d3c4 #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xd2/0x2b0 mm/kasan/report.c:521
 kasan_report+0x118/0x150 mm/kasan/report.c:634
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:189
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:400 [inline]
 __refcount_sub_and_test include/linux/refcount.h:389 [inline]
 __refcount_dec_and_test include/linux/refcount.h:432 [inline]
 refcount_dec_and_test include/linux/refcount.h:450 [inline]
 skb_unref include/linux/skbuff.h:1245 [inline]
 __sk_skb_reason_drop net/core/skbuff.c:1175 [inline]
 sk_skb_reason_drop+0x37/0x170 net/core/skbuff.c:1203
 kfree_skb_reason include/linux/skbuff.h:1275 [inline]
 kfree_skb include/linux/skbuff.h:1284 [inline]
 nr_transmit_buffer+0x11d/0x1b0 net/netrom/nr_out.c:210
 nr_establish_data_link+0x62/0xb0 net/netrom/nr_out.c:227
 nr_connect+0x6e6/0xde0 net/netrom/af_netrom.c:723
 __sys_connect_file net/socket.c:2038 [inline]
 __sys_connect+0x313/0x440 net/socket.c:2057
 __do_sys_connect net/socket.c:2063 [inline]
 __se_sys_connect net/socket.c:2060 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2060
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f564878e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f564958d038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f56489b6080 RCX: 00007f564878e929
RDX: 0000000000000048 RSI: 0000200000000300 RDI: 0000000000000004
RBP: 00007f5648810b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f56489b6080 R15: 00007ffdbc051128
 </TASK>

Allocated by task 5328:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4148 [inline]
 slab_alloc_node mm/slub.c:4197 [inline]
 kmem_cache_alloc_node_noprof+0x1bb/0x3c0 mm/slub.c:4249
 __alloc_skb+0x112/0x2d0 net/core/skbuff.c:660
 alloc_skb include/linux/skbuff.h:1336 [inline]
 nr_write_internal+0xe2/0xc60 net/netrom/nr_subr.c:144
 nr_establish_data_link+0x62/0xb0 net/netrom/nr_out.c:227
 nr_connect+0x6e6/0xde0 net/netrom/af_netrom.c:723
 __sys_connect_file net/socket.c:2038 [inline]
 __sys_connect+0x313/0x440 net/socket.c:2057
 __do_sys_connect net/socket.c:2063 [inline]
 __se_sys_connect net/socket.c:2060 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2060
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5328:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kmem_cache_free+0x18f/0x400 mm/slub.c:4745
 kfree_skb_reason include/linux/skbuff.h:1275 [inline]
 kfree_skb include/linux/skbuff.h:1284 [inline]
 nr_route_frame+0x467/0x7e0 net/netrom/nr_route.c:820
 nr_transmit_buffer+0xe7/0x1b0 net/netrom/nr_out.c:209
 nr_establish_data_link+0x62/0xb0 net/netrom/nr_out.c:227
 nr_connect+0x6e6/0xde0 net/netrom/af_netrom.c:723
 __sys_connect_file net/socket.c:2038 [inline]
 __sys_connect+0x313/0x440 net/socket.c:2057
 __do_sys_connect net/socket.c:2063 [inline]
 __se_sys_connect net/socket.c:2060 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2060
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888052e9cdc0
 which belongs to the cache skbuff_head_cache of size 240
The buggy address is located 228 bytes inside of
 freed 240-byte region [ffff888052e9cdc0, ffff888052e9ceb0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x52e9c
flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000000 ffff8880304fab40 dead000000000122 0000000000000000
raw: 0000000000000000 00000000000c000c 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5020, tgid 5020 (dhcpcd), ts 92136319816, free_ts 92134111122
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2451 [inline]
 allocate_slab+0x8a/0x3b0 mm/slub.c:2619
 new_slab mm/slub.c:2673 [inline]
 ___slab_alloc+0xbfc/0x1480 mm/slub.c:3859
 __slab_alloc mm/slub.c:3949 [inline]
 __slab_alloc_node mm/slub.c:4024 [inline]
 slab_alloc_node mm/slub.c:4185 [inline]
 kmem_cache_alloc_node_noprof+0x280/0x3c0 mm/slub.c:4249
 __alloc_skb+0x112/0x2d0 net/core/skbuff.c:660
 alloc_skb include/linux/skbuff.h:1336 [inline]
 alloc_skb_with_frags+0xca/0x890 net/core/skbuff.c:6668
 sock_alloc_send_pskb+0x857/0x990 net/core/sock.c:2999
 unix_dgram_sendmsg+0x4f6/0x1870 net/unix/af_unix.c:2071
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:727
 __sys_sendto+0x3bd/0x520 net/socket.c:2180
 __do_sys_sendto net/socket.c:2187 [inline]
 __se_sys_sendto net/socket.c:2183 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2183
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 15 tgid 15 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_frozen_pages+0xc71/0xe70 mm/page_alloc.c:2706
 pagetable_free include/linux/mm.h:2879 [inline]
 pagetable_dtor_free include/linux/mm.h:2977 [inline]
 __tlb_remove_table+0x2d2/0x3b0 include/asm-generic/tlb.h:220
 __tlb_remove_table_free mm/mmu_gather.c:227 [inline]
 tlb_remove_table_rcu+0x85/0x100 mm/mmu_gather.c:290
 rcu_do_batch kernel/rcu/tree.c:2576 [inline]
 rcu_core+0xca5/0x1710 kernel/rcu/tree.c:2832
 handle_softirqs+0x286/0x870 kernel/softirq.c:579
 run_ksoftirqd+0x9b/0x100 kernel/softirq.c:968
 smpboot_thread_fn+0x53f/0xa60 kernel/smpboot.c:164
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff888052e9cd80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
 ffff888052e9ce00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888052e9ce80: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc
                               ^
 ffff888052e9cf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888052e9cf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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