===================================================== BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249 CPU: 1 PID: 21883 Comm: syz-executor.5 Tainted: G W 5.12.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x24c/0x2e0 lib/dump_stack.c:120 kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:121 kmsan_internal_check_memory+0x1f5/0x500 mm/kmsan/kmsan.c:399 kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249 instrument_copy_to_user include/linux/instrumented.h:121 [inline] copyout lib/iov_iter.c:145 [inline] _copy_to_iter+0x72d/0x2bc0 lib/iov_iter.c:624 copy_to_iter include/linux/uio.h:137 [inline] simple_copy_to_iter+0xf6/0x150 net/core/datagram.c:519 __skb_datagram_iter+0x2cb/0x1210 net/core/datagram.c:425 skb_copy_datagram_iter+0xd8/0x200 net/core/datagram.c:533 skb_copy_datagram_msg include/linux/skbuff.h:3599 [inline] packet_recvmsg+0x764/0x2060 net/packet/af_packet.c:3405 sock_recvmsg_nosec net/socket.c:888 [inline] sock_recvmsg net/socket.c:906 [inline] sock_read_iter+0x59a/0x620 net/socket.c:979 call_read_iter include/linux/fs.h:1971 [inline] new_sync_read fs/read_write.c:415 [inline] vfs_read+0x136b/0x15a0 fs/read_write.c:496 ksys_read+0x275/0x500 fs/read_write.c:634 __do_sys_read fs/read_write.c:644 [inline] __se_sys_read+0x92/0xb0 fs/read_write.c:642 __x64_sys_read+0x4a/0x70 fs/read_write.c:642 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665d9 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f5e7cba0188 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665d9 RDX: 0000000000002020 RSI: 0000000020000240 RDI: 0000000000000003 RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 0000000000a9fb1f R14: 00007f5e7cba0300 R15: 0000000000022000 Uninit was stored to memory at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:120 [inline] kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:288 kmsan_memcpy_memmove_metadata+0x25e/0x2d0 mm/kmsan/kmsan.c:225 kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:245 __msan_memcpy+0x46/0x60 mm/kmsan/kmsan_instr.c:110 pskb_expand_head+0x3d6/0x1e20 net/core/skbuff.c:1685 __skb_cow include/linux/skbuff.h:3232 [inline] skb_cow_head include/linux/skbuff.h:3266 [inline] batadv_skb_head_push+0x2cc/0x410 net/batman-adv/soft-interface.c:73 batadv_send_skb_packet+0x1ed/0x970 net/batman-adv/send.c:86 batadv_send_broadcast_skb+0x76/0x90 net/batman-adv/send.c:127 batadv_iv_ogm_send_to_if net/batman-adv/bat_iv_ogm.c:393 [inline] batadv_iv_ogm_emit net/batman-adv/bat_iv_ogm.c:419 [inline] batadv_iv_send_outstanding_bat_ogm_packet+0xb2d/0xef0 net/batman-adv/bat_iv_ogm.c:1711 process_one_work+0x1219/0x1fe0 kernel/workqueue.c:2275 worker_thread+0x10ec/0x2340 kernel/workqueue.c:2421 kthread+0x521/0x560 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:120 [inline] kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:103 kmsan_slab_alloc+0x8e/0xe0 mm/kmsan/kmsan_hooks.c:76 slab_alloc_node mm/slub.c:2922 [inline] __kmalloc_node_track_caller+0xa4f/0x1470 mm/slub.c:4609 kmalloc_reserve net/core/skbuff.c:353 [inline] __alloc_skb+0x4dd/0xe90 net/core/skbuff.c:424 __netdev_alloc_skb+0x45d/0x810 net/core/skbuff.c:491 __netdev_alloc_skb_ip_align include/linux/skbuff.h:2884 [inline] netdev_alloc_skb_ip_align include/linux/skbuff.h:2894 [inline] batadv_iv_ogm_aggregate_new net/batman-adv/bat_iv_ogm.c:558 [inline] batadv_iv_ogm_queue_add+0x1376/0x1c40 net/batman-adv/bat_iv_ogm.c:670 batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:849 [inline] batadv_iv_ogm_schedule+0x12cd/0x16b0 net/batman-adv/bat_iv_ogm.c:869 batadv_iv_send_outstanding_bat_ogm_packet+0xd6e/0xef0 net/batman-adv/bat_iv_ogm.c:1723 process_one_work+0x1219/0x1fe0 kernel/workqueue.c:2275 worker_thread+0x10ec/0x2340 kernel/workqueue.c:2421 kthread+0x521/0x560 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Bytes 52-53 of 74 are uninitialized Memory access of size 74 starts at ffff888015756c40 Data copied to user address 000000002000024a =====================================================