[syzbot] [nfc?] memory leak in virtual_ncidev_write (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4f6b6c2b2f86 Merge tag 'riscv-for-linus-6.5-mw2' of git://..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1565b4e2a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=832b404e095b70c0
dashboard link: https://syzkaller.appspot.com/bug?extid=6b7c68d9c21e4ee4251b
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1296aa88a80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13e31cbca80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/894096f65e3a/disk-4f6b6c2b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fb7cd620415e/vmlinux-4f6b6c2b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5b6554eae0e7/bzImage-4f6b6c2b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6b7c68...@syzkaller.appspotmail.com

executing program
BUG: memory leak
unreferenced object 0xffff88810ac1a700 (size 240):
comm "syz-executor366", pid 5017, jiffies 4294944625 (age 12.970s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff83e1b1cd>] __alloc_skb+0x1fd/0x230 net/core/skbuff.c:634
[<ffffffff82c344e4>] alloc_skb include/linux/skbuff.h:1289 [inline]
[<ffffffff82c344e4>] virtual_ncidev_write+0x34/0xf0 drivers/nfc/virtual_ncidev.c:115
[<ffffffff8165e315>] vfs_write+0x175/0x570 fs/read_write.c:582
[<ffffffff8165e951>] ksys_write+0xa1/0x160 fs/read_write.c:637
[<ffffffff84a76ff9>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff84a76ff9>] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
[<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

BUG: memory leak
unreferenced object 0xffff888109c4b400 (size 640):
comm "syz-executor366", pid 5017, jiffies 4294944625 (age 12.970s)
hex dump (first 32 bytes):
10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff83e17a86>] kmalloc_reserve+0xe6/0x180 net/core/skbuff.c:559
[<ffffffff83e1b0a5>] __alloc_skb+0xd5/0x230 net/core/skbuff.c:644
[<ffffffff82c344e4>] alloc_skb include/linux/skbuff.h:1289 [inline]
[<ffffffff82c344e4>] virtual_ncidev_write+0x34/0xf0 drivers/nfc/virtual_ncidev.c:115
[<ffffffff8165e315>] vfs_write+0x175/0x570 fs/read_write.c:582
[<ffffffff8165e951>] ksys_write+0xa1/0x160 fs/read_write.c:637
[<ffffffff84a76ff9>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff84a76ff9>] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
[<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd



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