[syzbot] memory leak in virtual_ncidev_write

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    cc675d22e422 Merge tag 'for-linus-6.1-rc6-tag' of git://gi..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1152f8d9880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=435fb8cdd395f932
dashboard link: https://syzkaller.appspot.com/bug?extid=cdb9a427d1bc08815104
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=14bea8d9880000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10015c4e880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4f389db5cedc/disk-cc675d22.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c3ef1df08018/vmlinux-cc675d22.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e11bee4d6893/bzImage-cc675d22.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+cdb9a427d1bc08815104@xxxxxxxxxxxxxxxxxxxxxxxxx

executing program
BUG: memory leak
unreferenced object 0xffff88810e144e00 (size 240):
  comm "syz-executor284", pid 3701, jiffies 4294952403 (age 12.620s)
  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:
    [<ffffffff83ab79a9>] __alloc_skb+0x1f9/0x270 net/core/skbuff.c:497
    [<ffffffff82a5cf64>] alloc_skb include/linux/skbuff.h:1267 [inline]
    [<ffffffff82a5cf64>] virtual_ncidev_write+0x24/0xe0 drivers/nfc/virtual_ncidev.c:116
    [<ffffffff815f6503>] do_loop_readv_writev fs/read_write.c:759 [inline]
    [<ffffffff815f6503>] do_loop_readv_writev fs/read_write.c:743 [inline]
    [<ffffffff815f6503>] do_iter_write+0x253/0x300 fs/read_write.c:863
    [<ffffffff815f66ed>] vfs_writev+0xdd/0x240 fs/read_write.c:934
    [<ffffffff815f68f6>] do_writev+0xa6/0x1c0 fs/read_write.c:977
    [<ffffffff848802d5>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    [<ffffffff848802d5>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
    [<ffffffff84a00087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

BUG: memory leak
unreferenced object 0xffff88810cec1a00 (size 512):
  comm "syz-executor284", pid 3701, jiffies 4294952403 (age 12.620s)
  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:
    [<ffffffff814edca7>] __do_kmalloc_node mm/slab_common.c:954 [inline]
    [<ffffffff814edca7>] __kmalloc_node_track_caller+0x47/0x120 mm/slab_common.c:975
    [<ffffffff83ab788d>] kmalloc_reserve net/core/skbuff.c:437 [inline]
    [<ffffffff83ab788d>] __alloc_skb+0xdd/0x270 net/core/skbuff.c:509
    [<ffffffff82a5cf64>] alloc_skb include/linux/skbuff.h:1267 [inline]
    [<ffffffff82a5cf64>] virtual_ncidev_write+0x24/0xe0 drivers/nfc/virtual_ncidev.c:116
    [<ffffffff815f6503>] do_loop_readv_writev fs/read_write.c:759 [inline]
    [<ffffffff815f6503>] do_loop_readv_writev fs/read_write.c:743 [inline]
    [<ffffffff815f6503>] do_iter_write+0x253/0x300 fs/read_write.c:863
    [<ffffffff815f66ed>] vfs_writev+0xdd/0x240 fs/read_write.c:934
    [<ffffffff815f68f6>] do_writev+0xa6/0x1c0 fs/read_write.c:977
    [<ffffffff848802d5>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    [<ffffffff848802d5>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
    [<ffffffff84a00087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd



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