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

syz_tun: entered promiscuous mode
batadv_slave_0: entered promiscuous mode
=====================================================
BUG: KMSAN: uninit-value in hsr_get_node+0xd1e/0xd40 net/hsr/hsr_framereg.c:275
 hsr_get_node+0xd1e/0xd40 net/hsr/hsr_framereg.c:275
 fill_frame_info net/hsr/hsr_forward.c:678 [inline]
 hsr_forward_skb+0xe9d/0x3b40 net/hsr/hsr_forward.c:715
 hsr_handle_frame+0x914/0xbb0 net/hsr/hsr_slave.c:70
 __netif_receive_skb_core+0x1f19/0x6c90 net/core/dev.c:5554
 __netif_receive_skb_one_core net/core/dev.c:5658 [inline]
 __netif_receive_skb+0xca/0xa00 net/core/dev.c:5774
 netif_receive_skb_internal net/core/dev.c:5860 [inline]
 netif_receive_skb+0x58/0x660 net/core/dev.c:5920
 tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1549
 tun_get_user+0x5677/0x6b50 drivers/net/tun.c:2006
 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2052
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xb2f/0x1550 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+0x3490/0x3c10 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 __alloc_pages_noprof+0x9d6/0xe70 mm/page_alloc.c:4706
 alloc_pages_mpol_noprof+0x299/0x990 mm/mempolicy.c:2265
 alloc_pages_noprof+0x1bf/0x1e0 mm/mempolicy.c:2336
 skb_page_frag_refill+0x2bf/0x7c0 net/core/sock.c:2941
 tun_build_skb drivers/net/tun.c:1680 [inline]
 tun_get_user+0x1262/0x6b50 drivers/net/tun.c:1823
 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2052
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xb2f/0x1550 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+0x3490/0x3c10 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 PID: 5476 Comm: syz-executor.0 Not tainted 6.10.0-syzkaller-10729-g3c3ff7be9729-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
=====================================================


Tested on:

commit:         3c3ff7be Merge tag 'powerpc-6.11-1' of git://git.kerne..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13549349980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=bf984d38d0f9fb49
dashboard link: https://syzkaller.appspot.com/bug?extid=a81f2759d022496b40ab
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=150cd8ce980000