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BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249
CPU: 1 PID: 5389 Comm: syz-executor.3 Not tainted 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
 __ia32_sys_read+0x4a/0x70 fs/read_write.c:642
 do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline]
 __do_fast_syscall_32+0x127/0x180 arch/x86/entry/common.c:142
 do_fast_syscall_32+0x77/0xd0 arch/x86/entry/common.c:168
 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:211
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7fa7549
Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f55a15fc EFLAGS: 00000296 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000020000680
RDX: 0000000000002020 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

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 ffff8880b38ad040
Data copied to user address 0000000020000680
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