================================================================== BUG: KASAN: use-after-free in atomic_sub_return include/asm-generic/atomic-instrumented.h:159 [inline] BUG: KASAN: use-after-free in skb_release_data+0xe4/0x680 net/core/skbuff.c:566 Write of size 4 at addr ffff88807781e320 by task syz-executor.3/7565 CPU: 1 PID: 7565 Comm: syz-executor.3 Not tainted 5.0.0+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x113/0x167 lib/dump_stack.c:113 print_address_description.cold.5+0x9/0x1ff mm/kasan/report.c:187 kasan_report.cold.6+0x1b/0x39 mm/kasan/report.c:317 check_memory_region_inline mm/kasan/generic.c:185 [inline] check_memory_region+0x13e/0x1b0 mm/kasan/generic.c:191 kasan_check_write+0x14/0x20 mm/kasan/common.c:108 atomic_sub_return include/asm-generic/atomic-instrumented.h:159 [inline] skb_release_data+0xe4/0x680 net/core/skbuff.c:566 skb_release_all+0x3d/0x50 net/core/skbuff.c:631 __kfree_skb net/core/skbuff.c:645 [inline] kfree_skb+0x97/0x270 net/core/skbuff.c:663 skb_queue_purge+0x12/0x30 net/core/skbuff.c:2906 packet_release+0x7c2/0xae0 net/packet/af_packet.c:3026 __sock_release+0xc7/0x2a0 net/socket.c:599 sock_close+0x10/0x20 net/socket.c:1247 __fput+0x252/0x800 fs/file_table.c:278 ____fput+0x9/0x10 fs/file_table.c:309 task_work_run+0x10e/0x190 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x9ca/0x2e80 kernel/exit.c:876 do_group_exit+0xf4/0x2f0 kernel/exit.c:980 get_signal+0x2e7/0x1840 kernel/signal.c:2575 do_signal+0x87/0x1930 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x114/0x200 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x40d/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457879 Code: 8d b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 5b b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f00c36d6cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000000 RBX: 000000000071bf08 RCX: 0000000000457879 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000071bf08 RBP: 000000000071bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000071bf0c R13: 00007ffe0be894bf R14: 00007f00c36d7700 R15: 0000000000000000 Allocated by task 7565: save_stack+0x43/0xd0 mm/kasan/common.c:75 set_track mm/kasan/common.c:87 [inline] __kasan_kmalloc.constprop.9+0xc7/0xd0 mm/kasan/common.c:497 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:511 __do_kmalloc_node mm/slab.c:3686 [inline] __kmalloc_node_track_caller+0x4d/0x70 mm/slab.c:3700 __kmalloc_reserve.isra.38+0x2c/0xc0 net/core/skbuff.c:140 __alloc_skb+0xd7/0x570 net/core/skbuff.c:208 alloc_skb_fclone include/linux/skbuff.h:1107 [inline] sk_stream_alloc_skb+0x131/0xc80 net/ipv4/tcp.c:889 tcp_connect+0xd78/0x3fd0 net/ipv4/tcp_output.c:3521 tcp_v4_connect+0x1ac9/0x21b0 net/ipv4/tcp_ipv4.c:315 __inet_stream_connect+0x66b/0xd20 net/ipv4/af_inet.c:655 tcp_sendmsg_fastopen net/ipv4/tcp.c:1158 [inline] tcp_sendmsg_locked+0x20cb/0x36a0 net/ipv4/tcp.c:1200 tcp_sendmsg+0x27/0x40 net/ipv4/tcp.c:1434 inet_sendmsg+0x10d/0x460 net/ipv4/af_inet.c:798 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg+0xb7/0xf0 net/socket.c:661 __sys_sendto+0x1f2/0x2e0 net/socket.c:1932 __do_sys_sendto net/socket.c:1944 [inline] __se_sys_sendto net/socket.c:1940 [inline] __x64_sys_sendto+0xdc/0x1a0 net/socket.c:1940 do_syscall_64+0xd6/0x4e0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 7565: save_stack+0x43/0xd0 mm/kasan/common.c:75 set_track mm/kasan/common.c:87 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:459 kasan_slab_free+0xe/0x10 mm/kasan/common.c:467 __cache_free mm/slab.c:3498 [inline] kfree+0xcf/0x230 mm/slab.c:3821 skb_free_head+0x6e/0x90 net/core/skbuff.c:557 skb_release_data+0x478/0x680 net/core/skbuff.c:577 skb_release_all+0x3d/0x50 net/core/skbuff.c:631 __kfree_skb net/core/skbuff.c:645 [inline] kfree_skb+0x97/0x270 net/core/skbuff.c:663 skb_queue_purge+0x12/0x30 net/core/skbuff.c:2906 packet_release+0x7c2/0xae0 net/packet/af_packet.c:3026 __sock_release+0xc7/0x2a0 net/socket.c:599 sock_close+0x10/0x20 net/socket.c:1247 __fput+0x252/0x800 fs/file_table.c:278 ____fput+0x9/0x10 fs/file_table.c:309 task_work_run+0x10e/0x190 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x9ca/0x2e80 kernel/exit.c:876 do_group_exit+0xf4/0x2f0 kernel/exit.c:980 get_signal+0x2e7/0x1840 kernel/signal.c:2575 do_signal+0x87/0x1930 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x114/0x200 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x40d/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88807781e040 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 736 bytes inside of 1024-byte region [ffff88807781e040, ffff88807781e440) The buggy address belongs to the page: page:ffffea0001de0780 count:1 mapcount:0 mapping:ffff88802d400ac0 index:0x0 compound_mapcount: 0 flags: 0x5fffc0000010200(slab|head) raw: 05fffc0000010200 ffffea0001f7fa88 ffffea0001d2db88 ffff88802d400ac0 raw: 0000000000000000 ffff88807781e040 0000000100000007 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88807781e200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807781e280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807781e300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807781e380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807781e400: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ==================================================================