memory leak in gfs2_init_fs_context

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    f1f2f614 Merge branch 'next-integrity' of git://git.kernel..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15569c05600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4e93436f92b0cfde
dashboard link: https://syzkaller.appspot.com/bug?extid=c2fdfd2b783754878fb6
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10327c05600000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=105c9fd5600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+c2fdfd2b783754878fb6@xxxxxxxxxxxxxxxxxxxxxxxxx

udit: type=1400 audit(1569701659.045:64): avc:  denied  { map } for   
pid=6842 comm="syz-executor375" path="/root/syz-executor375626622"  
dev="sda1" ino=16502 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023  
tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
executing program
executing program
BUG: memory leak
unreferenced object 0xffff88810fd9a500 (size 256):
  comm "syz-executor375", pid 6845, jiffies 4294941255 (age 13.550s)
  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:
    [<00000000462ab467>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:43 [inline]
    [<00000000462ab467>] slab_post_alloc_hook mm/slab.h:586 [inline]
    [<00000000462ab467>] slab_alloc mm/slab.c:3319 [inline]
    [<00000000462ab467>] kmem_cache_alloc_trace+0x145/0x2c0 mm/slab.c:3548
    [<00000000b1a62211>] kmalloc include/linux/slab.h:552 [inline]
    [<00000000b1a62211>] kzalloc include/linux/slab.h:686 [inline]
    [<00000000b1a62211>] gfs2_init_fs_context+0x25/0x90  
fs/gfs2/ops_fstype.c:1543
    [<00000000db94ecb4>] gfs2_meta_init_fs_context+0x17/0x40  
fs/gfs2/ops_fstype.c:1608
    [<0000000077df5577>] alloc_fs_context+0x174/0x200 fs/fs_context.c:293
    [<000000008d5e3681>] fs_context_for_mount+0x25/0x30 fs/fs_context.c:307
    [<0000000030bafbdb>] __do_sys_fsopen fs/fsopen.c:137 [inline]
    [<0000000030bafbdb>] __se_sys_fsopen fs/fsopen.c:115 [inline]
    [<0000000030bafbdb>] __x64_sys_fsopen+0xa9/0x1a0 fs/fsopen.c:115
    [<00000000974fed69>] do_syscall_64+0x73/0x1f0  
arch/x86/entry/common.c:290
    [<00000000299e0e1b>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88810fd9a200 (size 256):
  comm "syz-executor375", pid 6846, jiffies 4294941838 (age 7.720s)
  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:
    [<00000000462ab467>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:43 [inline]
    [<00000000462ab467>] slab_post_alloc_hook mm/slab.h:586 [inline]
    [<00000000462ab467>] slab_alloc mm/slab.c:3319 [inline]
    [<00000000462ab467>] kmem_cache_alloc_trace+0x145/0x2c0 mm/slab.c:3548
    [<00000000b1a62211>] kmalloc include/linux/slab.h:552 [inline]
    [<00000000b1a62211>] kzalloc include/linux/slab.h:686 [inline]
    [<00000000b1a62211>] gfs2_init_fs_context+0x25/0x90  
fs/gfs2/ops_fstype.c:1543
    [<00000000db94ecb4>] gfs2_meta_init_fs_context+0x17/0x40  
fs/gfs2/ops_fstype.c:1608
    [<0000000077df5577>] alloc_fs_context+0x174/0x200 fs/fs_context.c:293
    [<000000008d5e3681>] fs_context_for_mount+0x25/0x30 fs/fs_context.c:307
    [<0000000030bafbdb>] __do_sys_fsopen fs/fsopen.c:137 [inline]
    [<0000000030bafbdb>] __se_sys_fsopen fs/fsopen.c:115 [inline]
    [<0000000030bafbdb>] __x64_sys_fsopen+0xa9/0x1a0 fs/fsopen.c:115
    [<00000000974fed69>] do_syscall_64+0x73/0x1f0  
arch/x86/entry/common.c:290
    [<00000000299e0e1b>] entry_SYSCALL_64_after_hwframe+0x44/0xa9



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