[syzbot] [block?] memory leak in null_init_zoned_dev

Hello,

syzbot found the following issue on:

HEAD commit:    06cf61899d64 Merge tag 'x86-urgent-2026-08-08' of git://gi..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=146d4149580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6843f8fd2336602d
dashboard link: https://syzkaller.appspot.com/bug?extid=f57d67a92532a98a562d
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=126d4149580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11531132580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e023ff6ad9bc/disk-06cf6189.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ea49527ba5df/vmlinux-06cf6189.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e3d6468d0490/bzImage-06cf6189.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

BUG: memory leak
unreferenced object 0xffff888126990000 (size 56000):
  comm "syz.0.17", pid 5947, jiffies 4294943074
  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 02 00 00 00 01 00 00 00  ................
  backtrace (crc 5c9573f8):
    ___kmalloc_large_node+0xbc/0x100 mm/slub.c:5287
    __kmalloc_large_node_noprof+0x1a/0xb0 mm/slub.c:5305
    __do_kmalloc_node mm/slub.c:5322 [inline]
    __kvmalloc_node_noprof+0x460/0x6f0 mm/slub.c:6905
    null_init_zoned_dev+0x108/0x520 drivers/block/null_blk/zoned.c:94
    null_add_dev+0x8a6/0xae0 drivers/block/null_blk/main.c:1993
    nullb_device_power_store+0xf9/0x1f0 drivers/block/null_blk/main.c:501
    flush_write_buffer fs/configfs/file.c:207 [inline]
    configfs_write_iter+0x10d/0x1a0 fs/configfs/file.c:229
    new_sync_write fs/read_write.c:595 [inline]
    vfs_write+0x3ac/0x720 fs/read_write.c:687
    ksys_write+0xa5/0x170 fs/read_write.c:739
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xf8/0x610 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

BUG: memory leak
unreferenced object 0xffff888127f80000 (size 56000):
  comm "syz.0.18", pid 5951, jiffies 4294943093
  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 02 00 00 00 01 00 00 00  ................
  backtrace (crc 5c9573f8):
    ___kmalloc_large_node+0xbc/0x100 mm/slub.c:5287
    __kmalloc_large_node_noprof+0x1a/0xb0 mm/slub.c:5305
    __do_kmalloc_node mm/slub.c:5322 [inline]
    __kvmalloc_node_noprof+0x460/0x6f0 mm/slub.c:6905
    null_init_zoned_dev+0x108/0x520 drivers/block/null_blk/zoned.c:94
    null_add_dev+0x8a6/0xae0 drivers/block/null_blk/main.c:1993
    nullb_device_power_store+0xf9/0x1f0 drivers/block/null_blk/main.c:501
    flush_write_buffer fs/configfs/file.c:207 [inline]
    configfs_write_iter+0x10d/0x1a0 fs/configfs/file.c:229
    new_sync_write fs/read_write.c:595 [inline]
    vfs_write+0x3ac/0x720 fs/read_write.c:687
    ksys_write+0xa5/0x170 fs/read_write.c:739
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xf8/0x610 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

connection error: failed to recv *flatrpc.ExecutorMessageRawT: EOF


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