Re: [syzbot] [net?] KMSAN: uninit-value in hsr_get_node (3)

[syzbot <syzbot+a81f2759d022496b40ab@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KMSAN: uninit-value in hsr_get_node

=====================================================
BUG: KMSAN: uninit-value in hsr_get_node+0xab0/0xad0 net/hsr/hsr_framereg.c:250
 hsr_get_node+0xab0/0xad0 net/hsr/hsr_framereg.c:250
 fill_frame_info net/hsr/hsr_forward.c:577 [inline]
 hsr_forward_skb+0x330/0x30e0 net/hsr/hsr_forward.c:615
 hsr_handle_frame+0xa20/0xb50 net/hsr/hsr_slave.c:69
 __netif_receive_skb_core+0x1cff/0x6190 net/core/dev.c:5432
 __netif_receive_skb_one_core net/core/dev.c:5536 [inline]
 __netif_receive_skb+0xca/0xa00 net/core/dev.c:5652
 netif_receive_skb_internal net/core/dev.c:5738 [inline]
 netif_receive_skb+0x58/0x660 net/core/dev.c:5798
 tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1549
 tun_get_user+0x5566/0x69e0 drivers/net/tun.c:2002
 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048
 call_write_iter include/linux/fs.h:2110 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xb63/0x1520 fs/read_write.c:590
 ksys_write+0x20f/0x4c0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x93/0xe0 fs/read_write.c:652
 x64_sys_call+0x3062/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 __alloc_pages+0x9d6/0xe70 mm/page_alloc.c:4598
 alloc_pages_mpol+0x299/0x990 mm/mempolicy.c:2264
 alloc_pages+0x1bf/0x1e0 mm/mempolicy.c:2335
 skb_page_frag_refill+0x2bf/0x7c0 net/core/sock.c:2921
 tun_build_skb drivers/net/tun.c:1679 [inline]
 tun_get_user+0x1258/0x69e0 drivers/net/tun.c:1819
 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048
 call_write_iter include/linux/fs.h:2110 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xb63/0x1520 fs/read_write.c:590
 ksys_write+0x20f/0x4c0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x93/0xe0 fs/read_write.c:652
 x64_sys_call+0x3062/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 PID: 5497 Comm: syz-executor.0 Not tainted 6.9.0-rc4-syzkaller-00038-g8cd26fd90c1a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
=====================================================


Tested on:

commit:         8cd26fd9 Merge tag 'for-6.9-rc4-tag' of git://git.kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1398c9ab180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=87a805e655619c64
dashboard link: https://syzkaller.appspot.com/bug?extid=a81f2759d022496b40ab
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.