================================================================== 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+0xe5/0x6f0 net/core/skbuff.c:600 Write of size 4 at addr ffff8881a5c3d8e0 by task syz-executor.0/21764 CPU: 0 PID: 21764 Comm: syz-executor.0 Not tainted 5.4.49-syzkaller-00898-g54ec87ec7a59 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x14a/0x1ce lib/dump_stack.c:118 print_address_description+0x93/0x620 mm/kasan/report.c:374 __kasan_report+0x16d/0x1e0 mm/kasan/report.c:506 kasan_report+0x36/0x60 mm/kasan/common.c:634 check_memory_region_inline mm/kasan/generic.c:181 [inline] check_memory_region+0x2b5/0x2f0 mm/kasan/generic.c:191 atomic_sub_return include/asm-generic/atomic-instrumented.h:159 [inline] skb_release_data+0xe5/0x6f0 net/core/skbuff.c:600 skb_release_all net/core/skbuff.c:665 [inline] __kfree_skb+0x55/0x180 net/core/skbuff.c:679 sit_tunnel_xmit+0x443/0x24d0 net/ipv6/sit.c:1054 __netdev_start_xmit include/linux/netdevice.h:4467 [inline] netdev_start_xmit include/linux/netdevice.h:4481 [inline] xmit_one+0x219/0x460 net/core/dev.c:3196 dev_hard_start_xmit net/core/dev.c:3212 [inline] __dev_queue_xmit+0x18d9/0x2680 net/core/dev.c:3771 packet_sendmsg_spkt+0x10a8/0x1730 net/packet/af_packet.c:1991 sock_sendmsg_nosec net/socket.c:638 [inline] sock_sendmsg net/socket.c:658 [inline] ____sys_sendmsg+0x58a/0x8d0 net/socket.c:2298 ___sys_sendmsg net/socket.c:2352 [inline] __sys_sendmmsg+0x3b0/0x730 net/socket.c:2455 __do_sys_sendmmsg net/socket.c:2484 [inline] __se_sys_sendmmsg net/socket.c:2481 [inline] __x64_sys_sendmmsg+0x9c/0xb0 net/socket.c:2481 do_syscall_64+0xcb/0x150 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cb19 Code: 0d b7 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 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fb8fd411c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00000000004fd680 RCX: 000000000045cb19 RDX: 0000000000000001 RSI: 0000000020003700 RDI: 0000000000000003 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000902 R14: 00000000004cbde8 R15: 00007fb8fd4126d4 Allocated by task 21764: save_stack mm/kasan/common.c:69 [inline] set_track mm/kasan/common.c:77 [inline] __kasan_kmalloc+0x12c/0x1c0 mm/kasan/common.c:510 slab_post_alloc_hook mm/slab.h:584 [inline] slab_alloc_node mm/slub.c:2766 [inline] slab_alloc mm/slub.c:2774 [inline] __kmalloc_track_caller+0x201/0x2c0 mm/slub.c:4353 __kmalloc_reserve net/core/skbuff.c:141 [inline] __alloc_skb+0xd1/0x4d0 net/core/skbuff.c:209 alloc_skb include/linux/skbuff.h:1055 [inline] sock_wmalloc+0xaa/0x3d0 net/core/sock.c:2098 packet_sendmsg_spkt+0x3f8/0x1730 net/packet/af_packet.c:1938 sock_sendmsg_nosec net/socket.c:638 [inline] sock_sendmsg net/socket.c:658 [inline] ____sys_sendmsg+0x58a/0x8d0 net/socket.c:2298 ___sys_sendmsg net/socket.c:2352 [inline] __sys_sendmmsg+0x3b0/0x730 net/socket.c:2455 __do_sys_sendmmsg net/socket.c:2484 [inline] __se_sys_sendmmsg net/socket.c:2481 [inline] __x64_sys_sendmmsg+0x9c/0xb0 net/socket.c:2481 do_syscall_64+0xcb/0x150 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 21764: save_stack mm/kasan/common.c:69 [inline] set_track mm/kasan/common.c:77 [inline] kasan_set_free_info mm/kasan/common.c:332 [inline] __kasan_slab_free+0x181/0x230 mm/kasan/common.c:471 slab_free_hook mm/slub.c:1424 [inline] slab_free_freelist_hook+0xd0/0x150 mm/slub.c:1457 slab_free mm/slub.c:3014 [inline] kfree+0x12b/0x600 mm/slub.c:3975 skb_release_all net/core/skbuff.c:665 [inline] __kfree_skb+0x55/0x180 net/core/skbuff.c:679 packet_rcv+0x151/0x1410 net/packet/af_packet.c:2153 dev_queue_xmit_nit+0x946/0x9e0 net/core/dev.c:1991 xmit_one+0x7b/0x460 net/core/dev.c:3192 dev_hard_start_xmit net/core/dev.c:3212 [inline] __dev_queue_xmit+0x18d9/0x2680 net/core/dev.c:3771 packet_sendmsg_spkt+0x10a8/0x1730 net/packet/af_packet.c:1991 sock_sendmsg_nosec net/socket.c:638 [inline] sock_sendmsg net/socket.c:658 [inline] ____sys_sendmsg+0x58a/0x8d0 net/socket.c:2298 ___sys_sendmsg net/socket.c:2352 [inline] __sys_sendmmsg+0x3b0/0x730 net/socket.c:2455 __do_sys_sendmmsg net/socket.c:2484 [inline] __se_sys_sendmmsg net/socket.c:2481 [inline] __x64_sys_sendmmsg+0x9c/0xb0 net/socket.c:2481 do_syscall_64+0xcb/0x150 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff8881a5c3d800 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 224 bytes inside of 512-byte region [ffff8881a5c3d800, ffff8881a5c3da00) The buggy address belongs to the page: page:ffffea0006970f00 refcount:1 mapcount:0 mapping:ffff8881da802500 index:0xffff8881a5c3f000 compound_mapcount: 0 flags: 0x8000000000010200(slab|head) raw: 8000000000010200 ffffea0006a39700 0000000700000007 ffff8881da802500 raw: ffff8881a5c3f000 000000008010000e 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881a5c3d780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881a5c3d800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881a5c3d880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881a5c3d900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881a5c3d980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================