memory leak in erase_aeb

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    ad910e36 pipe: fix poll/select race introduced by the pipe..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16080232e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3beca47aecbf4a9c
dashboard link: https://syzkaller.appspot.com/bug?extid=f317896aae32eb281a58
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14b527f2e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+f317896aae32eb281a58@xxxxxxxxxxxxxxxxxxxxxxxxx

BUG: memory leak
unreferenced object 0xffff8881225039a0 (size 32):
  comm "syz-executor.0", pid 7318, jiffies 4294950453 (age 8.280s)
  hex dump (first 32 bytes):
    00 00 00 00 03 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 01 00 00 00 02 00 00 00  ................
  backtrace:
    [<000000003a9d0e7e>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:43 [inline]
    [<000000003a9d0e7e>] slab_post_alloc_hook mm/slab.h:586 [inline]
    [<000000003a9d0e7e>] slab_alloc mm/slab.c:3320 [inline]
    [<000000003a9d0e7e>] kmem_cache_alloc+0x13f/0x2c0 mm/slab.c:3484
    [<00000000b53dfd0a>] erase_aeb+0x2a/0x100 drivers/mtd/ubi/wl.c:1691
    [<000000005ccfba82>] ubi_wl_init+0x1ae/0x600 drivers/mtd/ubi/wl.c:1758
    [<000000002350928f>] ubi_attach+0x665/0x18e7  
drivers/mtd/ubi/attach.c:1605
    [<0000000055aac88b>] ubi_attach_mtd_dev+0x5b3/0xd40  
drivers/mtd/ubi/build.c:946
    [<00000000071dc178>] ctrl_cdev_ioctl+0x149/0x1c0  
drivers/mtd/ubi/cdev.c:1043
    [<000000004c359338>] vfs_ioctl fs/ioctl.c:47 [inline]
    [<000000004c359338>] file_ioctl fs/ioctl.c:545 [inline]
    [<000000004c359338>] do_vfs_ioctl+0x551/0x890 fs/ioctl.c:732
    [<000000002f3b4a0e>] ksys_ioctl+0x86/0xb0 fs/ioctl.c:749
    [<0000000071dee951>] __do_sys_ioctl fs/ioctl.c:756 [inline]
    [<0000000071dee951>] __se_sys_ioctl fs/ioctl.c:754 [inline]
    [<0000000071dee951>] __x64_sys_ioctl+0x1e/0x30 fs/ioctl.c:754
    [<0000000069d4ede5>] do_syscall_64+0x73/0x220  
arch/x86/entry/common.c:294
    [<000000001a44675f>] entry_SYSCALL_64_after_hwframe+0x44/0xa9



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