Message-ID: <20180426152545.GB68594@jaegeuk-macbookpro.roam.corp.google.com>
Date:   Thu, 26 Apr 2018 09:25:45 -0600
From:   Jaegeuk Kim <jaegeuk@...nel.org>
To:     Chao Yu <chao@...nel.org>
Cc:     linux-kernel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH 1/5] f2fs: give message and set need_fsck
 given broken node id

On 04/25, Chao Yu wrote:
> On 2018/4/25 13:46, Jaegeuk Kim wrote:
> > syzbot hit the following crash on upstream commit
> > 83beed7b2b26f232d782127792dd0cd4362fdc41 (Fri Apr 20 17:56:32 2018 +0000)
> > Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/evalenti/linux-soc-thermal
> > syzbot dashboard link: https://syzkaller.appspot.com/bug?extid=d154ec99402c6f628887
> > 
> > C reproducer: https://syzkaller.appspot.com/x/repro.c?id=5414336294027264
> > syzkaller reproducer: https://syzkaller.appspot.com/x/repro.syz?id=5471683234234368
> > Raw console output: https://syzkaller.appspot.com/x/log.txt?id=5436660795834368
> > Kernel config: https://syzkaller.appspot.com/x/.config?id=1808800213120130118
> > compiler: gcc (GCC) 8.0.1 20180413 (experimental)
> > 
> > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > Reported-by: syzbot+d154ec99402c6f628887@...kaller.appspotmail.com
> > It will help syzbot understand when the bug is fixed. See footer for details.
> > If you forward the report, please keep this part and the footer.
> > 
> > F2FS-fs (loop0): Magic Mismatch, valid(0xf2f52010) - read(0x0)
> > F2FS-fs (loop0): Can't find valid F2FS filesystem in 1th superblock
> > F2FS-fs (loop0): invalid crc value
> > ------------[ cut here ]------------
> > kernel BUG at fs/f2fs/node.c:1185!
> > invalid opcode: 0000 [#1] SMP KASAN
> > Dumping ftrace buffer:
> >    (ftrace buffer empty)
> > Modules linked in:
> > CPU: 1 PID: 4549 Comm: syzkaller704305 Not tainted 4.17.0-rc1+ #10
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> > RIP: 0010:__get_node_page+0xb68/0x16e0 fs/f2fs/node.c:1185
> > RSP: 0018:ffff8801d960e820 EFLAGS: 00010293
> > RAX: ffff8801d88205c0 RBX: 0000000000000003 RCX: ffffffff82f6cc06
> > RDX: 0000000000000000 RSI: ffffffff82f6d5e8 RDI: 0000000000000004
> > RBP: ffff8801d960ec30 R08: ffff8801d88205c0 R09: ffffed003b5e46c2
> > R10: 0000000000000003 R11: 0000000000000003 R12: ffff8801a86e00c0
> > R13: 0000000000000001 R14: ffff8801a86e0530 R15: ffff8801d9745240
> > FS:  000000000072c880(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 00007f3d403209b8 CR3: 00000001d8f3f000 CR4: 00000000001406e0
> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > Call Trace:
> >  get_node_page fs/f2fs/node.c:1237 [inline]
> >  truncate_xattr_node+0x152/0x2e0 fs/f2fs/node.c:1014
> >  remove_inode_page+0x200/0xaf0 fs/f2fs/node.c:1039
> >  f2fs_evict_inode+0xe86/0x1710 fs/f2fs/inode.c:547
> >  evict+0x4a6/0x960 fs/inode.c:557
> >  iput_final fs/inode.c:1519 [inline]
> >  iput+0x62d/0xa80 fs/inode.c:1545
> >  f2fs_fill_super+0x5f4e/0x7bf0 fs/f2fs/super.c:2849
> >  mount_bdev+0x30c/0x3e0 fs/super.c:1164
> >  f2fs_mount+0x34/0x40 fs/f2fs/super.c:3020
> >  mount_fs+0xae/0x328 fs/super.c:1267
> >  vfs_kern_mount.part.34+0xd4/0x4d0 fs/namespace.c:1037
> >  vfs_kern_mount fs/namespace.c:1027 [inline]
> >  do_new_mount fs/namespace.c:2518 [inline]
> >  do_mount+0x564/0x3070 fs/namespace.c:2848
> >  ksys_mount+0x12d/0x140 fs/namespace.c:3064
> >  __do_sys_mount fs/namespace.c:3078 [inline]
> >  __se_sys_mount fs/namespace.c:3075 [inline]
> >  __x64_sys_mount+0xbe/0x150 fs/namespace.c:3075
> >  do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
> >  entry_SYSCALL_64_after_hwframe+0x49/0xbe
> > RIP: 0033:0x443dea
> > RSP: 002b:00007ffcc7882368 EFLAGS: 00000297 ORIG_RAX: 00000000000000a5
> > RAX: ffffffffffffffda RBX: 0000000020000c00 RCX: 0000000000443dea
> > RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffcc7882370
> > RBP: 0000000000000003 R08: 0000000020016a00 R09: 000000000000000a
> > R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000004
> > R13: 0000000000402ce0 R14: 0000000000000000 R15: 0000000000000000
> > RIP: __get_node_page+0xb68/0x16e0 fs/f2fs/node.c:1185 RSP: ffff8801d960e820
> > ---[ end trace 4edbeb71f002bb76 ]---
> > 
> > Reported-and-tested-by: syzbot+d154ec99402c6f628887@...kaller.appspotmail.com
> > Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
> > ---
> >  fs/f2fs/f2fs.h  | 13 +------------
> >  fs/f2fs/inode.c | 13 ++++++-------
> >  fs/f2fs/node.c  | 23 +++++++++++++++++++++--
> >  3 files changed, 28 insertions(+), 21 deletions(-)
> > 
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index 8f3ad9662d13..d26aae5bf00d 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -1583,18 +1583,6 @@ static inline bool __exist_node_summaries(struct f2fs_sb_info *sbi)
> >  			is_set_ckpt_flags(sbi, CP_FASTBOOT_FLAG));
> >  }
> >  
> > -/*
> > - * Check whether the given nid is within node id range.
> > - */
> > -static inline int check_nid_range(struct f2fs_sb_info *sbi, nid_t nid)
> > -{
> > -	if (unlikely(nid < F2FS_ROOT_INO(sbi)))
> > -		return -EINVAL;
> > -	if (unlikely(nid >= NM_I(sbi)->max_nid))
> > -		return -EINVAL;
> > -	return 0;
> > -}
> > -
> >  /*
> >   * Check whether the inode has blocks or not
> >   */
> > @@ -2768,6 +2756,7 @@ f2fs_hash_t f2fs_dentry_hash(const struct qstr *name_info,
> >  struct dnode_of_data;
> >  struct node_info;
> >  
> > +int check_nid_range(struct f2fs_sb_info *sbi, nid_t nid);
> >  bool available_free_memory(struct f2fs_sb_info *sbi, int type);
> >  int need_dentry_mark(struct f2fs_sb_info *sbi, nid_t nid);
> >  bool is_checkpointed_node(struct f2fs_sb_info *sbi, nid_t nid);
> > diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> > index 176f8e84bb6e..414b1ede642b 100644
> > --- a/fs/f2fs/inode.c
> > +++ b/fs/f2fs/inode.c
> > @@ -194,12 +194,8 @@ static int do_read_inode(struct inode *inode)
> >  	projid_t i_projid;
> >  
> >  	/* Check if ino is within scope */
> > -	if (check_nid_range(sbi, inode->i_ino)) {
> > -		f2fs_msg(inode->i_sb, KERN_ERR, "bad inode number: %lu",
> > -			 (unsigned long) inode->i_ino);
> > -		WARN_ON(1);
> > +	if (check_nid_range(sbi, inode->i_ino))
> >  		return -EINVAL;
> > -	}
> >  
> >  	node_page = get_node_page(sbi, inode->i_ino);
> >  	if (IS_ERR(node_page))
> > @@ -588,8 +584,11 @@ void f2fs_evict_inode(struct inode *inode)
> >  		alloc_nid_failed(sbi, inode->i_ino);
> >  		clear_inode_flag(inode, FI_FREE_NID);
> >  	} else {
> > -		f2fs_bug_on(sbi, err &&
> > -			!exist_written_data(sbi, inode->i_ino, ORPHAN_INO));
> > +		/*
> > +		 * If xattr nid is corrupted, we can reach out error condition,
> > +		 * err & !exist_written_data(sbi, inode->i_ino, ORPHAN_INO)).
> > +		 * In that case, check_nid_range() is enough to give a clue.
> > +		 */
> >  	}
> >  out_clear:
> >  	fscrypt_put_encryption_info(inode);
> > diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> > index 3a3d38b3e9ec..2dd34cd980b1 100644
> > --- a/fs/f2fs/node.c
> > +++ b/fs/f2fs/node.c
> > @@ -29,6 +29,21 @@ static struct kmem_cache *nat_entry_slab;
> >  static struct kmem_cache *free_nid_slab;
> >  static struct kmem_cache *nat_entry_set_slab;
> >  
> > +/*
> > + * Check whether the given nid is within node id range.
> > + */
> > +int check_nid_range(struct f2fs_sb_info *sbi, nid_t nid)
> > +{
> > +	if (unlikely(nid < F2FS_ROOT_INO(sbi) || nid >= NM_I(sbi)->max_nid)) {
> > +		set_sbi_flag(sbi, SBI_NEED_FSCK);
> > +		f2fs_msg(sbi->sb, KERN_WARNING,
> > +				"%s: out-of-range nid=%x, run fsck to fix.",
> > +				__func__, nid);
> > +		return -EINVAL;
> > +	}
> > +	return 0;
> > +}
> > +
> >  bool available_free_memory(struct f2fs_sb_info *sbi, int type)
> >  {
> >  	struct f2fs_nm_info *nm_i = NM_I(sbi);
> > @@ -1010,6 +1025,8 @@ int truncate_xattr_node(struct inode *inode)
> >  
> >  	if (!nid)
> >  		return 0;
> > +	if (check_nid_range(sbi, nid))
> > +		return -EINVAL;
> 
> Below get_node_page() will call check_nid_range(), so above check is redundant.

Done.

> 
> Thanks,
> 
> >  
> >  	npage = get_node_page(sbi, nid);
> >  	if (IS_ERR(npage))
> > @@ -1158,7 +1175,8 @@ void ra_node_page(struct f2fs_sb_info *sbi, nid_t nid)
> >  
> >  	if (!nid)
> >  		return;
> > -	f2fs_bug_on(sbi, check_nid_range(sbi, nid));
> > +	if (check_nid_range(sbi, nid))
> > +		return;
> >  
> >  	rcu_read_lock();
> >  	apage = radix_tree_lookup(&NODE_MAPPING(sbi)->i_pages, nid);
> > @@ -1182,7 +1200,8 @@ static struct page *__get_node_page(struct f2fs_sb_info *sbi, pgoff_t nid,
> >  
> >  	if (!nid)
> >  		return ERR_PTR(-ENOENT);
> > -	f2fs_bug_on(sbi, check_nid_range(sbi, nid));
> > +	if (check_nid_range(sbi, nid))
> > +		return ERR_PTR(-EINVAL);
> >  repeat:
> >  	page = f2fs_grab_cache_page(NODE_MAPPING(sbi), nid, false);
> >  	if (!page)
> > 

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