[PATCH] debugfs: add fsd's methods initialization

[Edward Adam Davis <eadavis@qq.com>]

syzbot reported a uninit-value in full_proxy_unlocked_ioctl. [1]

The newly created fsd does not initialize methods, and increases the
initialization of methods for fsd.

[1]
BUG: KMSAN: uninit-value in full_proxy_unlocked_ioctl+0xed/0x3a0 fs/debugfs/file.c:399
 full_proxy_unlocked_ioctl+0xed/0x3a0 fs/debugfs/file.c:399
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0x246/0x440 fs/ioctl.c:892
 __x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:892
 x64_sys_call+0x19f0/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Fixes: 41a0ecc0997c ("debugfs: get rid of dynamically allocation proxy_ops")
Reported-by: syzbot+8928e473a91452caca2f@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=8928e473a91452caca2f
Tested-by: syzbot+8928e473a91452caca2f@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
 fs/debugfs/file.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index e33cc77699cd..5fbefce2b372 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -102,6 +102,7 @@ static int __debugfs_file_get(struct dentry *dentry, enum dbgfs_get_mode mode)
 		if (!fsd)
 			return -ENOMEM;
 
+		fsd->methods = 0;
 		if (mode == DBGFS_GET_SHORT) {
 			const struct debugfs_short_fops *ops;
 			ops = fsd->short_fops = DEBUGFS_I(inode)->short_fops;
-- 
2.43.0