================================================================== BUG: KASAN: use-after-free in css_task_iter_advance+0x49b/0x540 kernel/cgroup/cgroup.c:4507 Read of size 4 at addr ffff88808b3c6adc by task syz-executor.1/26039 CPU: 1 PID: 26039 Comm: syz-executor.1 Not tainted 5.2.0-rc3-next-20190607 #11 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+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0xd4/0x306 mm/kasan/report.c:351 __kasan_report.cold+0x1b/0x36 mm/kasan/report.c:482 kasan_report+0x12/0x20 mm/kasan/common.c:614 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131 css_task_iter_advance+0x49b/0x540 kernel/cgroup/cgroup.c:4507 css_task_iter_start+0x18b/0x230 kernel/cgroup/cgroup.c:4543 mem_cgroup_scan_tasks+0xaf/0x180 mm/memcontrol.c:1167 select_bad_process mm/oom_kill.c:374 [inline] out_of_memory mm/oom_kill.c:1088 [inline] out_of_memory+0x6b2/0x1280 mm/oom_kill.c:1035 mem_cgroup_out_of_memory+0x1ca/0x230 mm/memcontrol.c:1573 mem_cgroup_oom mm/memcontrol.c:1905 [inline] try_charge+0xfbe/0x1480 mm/memcontrol.c:2468 mem_cgroup_try_charge+0x24d/0x5e0 mm/memcontrol.c:6073 mem_cgroup_try_charge_delay+0x1f/0xa0 mm/memcontrol.c:6088 do_anonymous_page mm/memory.c:3036 [inline] handle_pte_fault mm/memory.c:3890 [inline] __handle_mm_fault+0x1e1a/0x3eb0 mm/memory.c:4016 handle_mm_fault+0x3b7/0xa90 mm/memory.c:4053 do_user_addr_fault arch/x86/mm/fault.c:1455 [inline] __do_page_fault+0x5ef/0xda0 arch/x86/mm/fault.c:1521 do_page_fault+0x71/0x57d arch/x86/mm/fault.c:1552 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1156 RIP: 0033:0x410bbf Code: 0f 84 c8 02 00 00 48 83 bd 78 ff ff ff 00 0f 84 f9 04 00 00 48 8b 95 68 ff ff ff 44 89 95 38 ff ff ff 4c 8d ac 10 00 f7 ff ff <49> 89 85 90 06 00 00 49 8d 85 10 03 00 00 49 89 95 98 06 00 00 41 RSP: 002b:00007fffee1a3ea0 EFLAGS: 00010206 RAX: 00007f2f444b5000 RBX: 0000000000020000 RCX: 00000000004592ca RDX: 0000000000021000 RSI: 0000000000021000 RDI: 0000000000000000 RBP: 00007fffee1a3f80 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffee1a4070 R13: 00007f2f444d5700 R14: 0000000000000001 R15: 000000000075bfcc Allocated by task 8359: save_stack+0x23/0x90 mm/kasan/common.c:71 set_track mm/kasan/common.c:79 [inline] __kasan_kmalloc mm/kasan/common.c:489 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:503 __do_kmalloc_node mm/slab.c:3614 [inline] __kmalloc_node_track_caller+0x4e/0x70 mm/slab.c:3628 __kmalloc_reserve.isra.0+0x40/0xf0 net/core/skbuff.c:139 __alloc_skb+0x10b/0x5e0 net/core/skbuff.c:207 alloc_skb_fclone include/linux/skbuff.h:1104 [inline] sk_stream_alloc_skb+0x2d2/0xc50 net/ipv4/tcp.c:870 tcp_sendmsg_locked+0xc85/0x3920 net/ipv4/tcp.c:1257 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1415 inet_sendmsg+0x141/0x5d0 net/ipv4/af_inet.c:798 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:665 sock_write_iter+0x27c/0x3e0 net/socket.c:994 call_write_iter include/linux/fs.h:1870 [inline] new_sync_write+0x4d3/0x770 fs/read_write.c:483 __vfs_write+0xe1/0x110 fs/read_write.c:496 vfs_write+0x268/0x5d0 fs/read_write.c:558 ksys_write+0x14f/0x290 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write fs/read_write.c:620 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:620 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 9: save_stack+0x23/0x90 mm/kasan/common.c:71 set_track mm/kasan/common.c:79 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459 __cache_free mm/slab.c:3426 [inline] kfree+0x106/0x2a0 mm/slab.c:3753 skb_free_head+0x93/0xb0 net/core/skbuff.c:589 skb_release_data+0x42d/0x7c0 net/core/skbuff.c:609 skb_release_all+0x4d/0x60 net/core/skbuff.c:663 __kfree_skb+0x16/0x30 net/core/skbuff.c:677 sk_wmem_free_skb include/net/sock.h:1476 [inline] tcp_rtx_queue_unlink_and_free include/net/tcp.h:1785 [inline] tcp_clean_rtx_queue net/ipv4/tcp_input.c:3143 [inline] tcp_ack+0x1c28/0x5870 net/ipv4/tcp_input.c:3670 tcp_rcv_established+0x18c7/0x1fa0 net/ipv4/tcp_input.c:5560 tcp_v4_do_rcv+0x610/0x8c0 net/ipv4/tcp_ipv4.c:1536 tcp_v4_rcv+0x2dc8/0x3870 net/ipv4/tcp_ipv4.c:1917 ip_protocol_deliver_rcu+0x5a/0x8e0 net/ipv4/ip_input.c:204 ip_local_deliver_finish+0x23b/0x390 net/ipv4/ip_input.c:231 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_local_deliver+0x1e9/0x520 net/ipv4/ip_input.c:252 dst_input include/net/dst.h:439 [inline] ip_rcv_finish+0x1d9/0x2f0 net/ipv4/ip_input.c:413 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_rcv+0xe8/0x3f0 net/ipv4/ip_input.c:523 __netif_receive_skb_one_core+0x113/0x1a0 net/core/dev.c:4981 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5095 netif_receive_skb_internal+0x108/0x390 net/core/dev.c:5185 napi_skb_finish net/core/dev.c:5648 [inline] napi_gro_receive+0x52d/0x740 net/core/dev.c:5681 receive_buf+0xf8a/0x57c0 drivers/net/virtio_net.c:1061 virtnet_receive drivers/net/virtio_net.c:1323 [inline] virtnet_poll+0x5f8/0xe82 drivers/net/virtio_net.c:1428 napi_poll net/core/dev.c:6329 [inline] net_rx_action+0x4f5/0x1070 net/core/dev.c:6395 __do_softirq+0x25c/0x94c kernel/softirq.c:293 The buggy address belongs to the object at ffff88808b3c6900 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 476 bytes inside of 1024-byte region [ffff88808b3c6900, ffff88808b3c6d00) The buggy address belongs to the page: page:ffffea00022cf180 refcount:1 mapcount:0 mapping:ffff8880aa400ac0 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea0002914b08 ffffea00016f4388 ffff8880aa400ac0 raw: 0000000000000000 ffff88808b3c6000 0000000100000007 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808b3c6980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808b3c6a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88808b3c6a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88808b3c6b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808b3c6b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================