2022-08-02 01:49:29

by Jaegeuk Kim

[permalink] [raw]
Subject: Re: [f2fs-dev] [PATCH -next v2] f2fs: fix null-ptr-deref in f2fs_get_dnode_of_data

On 08/01, Daeho Jeong wrote:
> On Mon, Aug 1, 2022 at 4:15 AM Ye Bin via Linux-f2fs-devel
> <[email protected]> wrote:
> >
> > There is issue as follows when test f2fs atomic write:
> > F2FS-fs (loop0): Can't find valid F2FS filesystem in 2th superblock
> > F2FS-fs (loop0): invalid crc_offset: 0
> > F2FS-fs (loop0): f2fs_check_nid_range: out-of-range nid=1, run fsck to fix.
> > F2FS-fs (loop0): f2fs_check_nid_range: out-of-range nid=2, run fsck to fix.
> > ==================================================================
> > BUG: KASAN: null-ptr-deref in f2fs_get_dnode_of_data+0xac/0x16d0
> > Read of size 8 at addr 0000000000000028 by task rep/1990
> >
> > CPU: 4 PID: 1990 Comm: rep Not tainted 5.19.0-rc6-next-20220715 #266
> > Call Trace:
> > <TASK>
> > dump_stack_lvl+0x6e/0x91
> > print_report.cold+0x49a/0x6bb
> > kasan_report+0xa8/0x130
> > f2fs_get_dnode_of_data+0xac/0x16d0
> > f2fs_do_write_data_page+0x2a5/0x1030
> > move_data_page+0x3c5/0xdf0
> > do_garbage_collect+0x2015/0x36c0
> > f2fs_gc+0x554/0x1d30
> > f2fs_balance_fs+0x7f5/0xda0
> > f2fs_write_single_data_page+0xb66/0xdc0
> > f2fs_write_cache_pages+0x716/0x1420
> > f2fs_write_data_pages+0x84f/0x9a0
> > do_writepages+0x130/0x3a0
> > filemap_fdatawrite_wbc+0x87/0xa0
> > file_write_and_wait_range+0x157/0x1c0
> > f2fs_do_sync_file+0x206/0x12d0
> > f2fs_sync_file+0x99/0xc0
> > vfs_fsync_range+0x75/0x140
> > f2fs_file_write_iter+0xd7b/0x1850
> > vfs_write+0x645/0x780
> > ksys_write+0xf1/0x1e0
> > do_syscall_64+0x3b/0x90
> > entry_SYSCALL_64_after_hwframe+0x63/0xcd
> >
> > As 3db1de0e582c commit changed atomic write way which new a cow_inode for
> > atomic write file, and also mark cow_inode as FI_ATOMIC_FILE.
> > When f2fs_do_write_data_page write cow_inode will use cow_inode's cow_inode
> > which is NULL. Then will trigger null-ptr-deref.
> > To solve above issue, introduce FI_COW_FILE flag for COW inode.
> >
> > Fiexes: 3db1de0e582c("f2fs: change the current atomic write way")
> > Signed-off-by: Ye Bin <[email protected]>
> > ---
> > fs/f2fs/f2fs.h | 6 ++++++
> > fs/f2fs/file.c | 2 +-
> > fs/f2fs/segment.c | 5 +++--
> > 3 files changed, 10 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index 8579b59b8a05..101f0064ee25 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -758,6 +758,7 @@ enum {
> > FI_ENABLE_COMPRESS, /* enable compression in "user" compression mode */
> > FI_COMPRESS_RELEASED, /* compressed blocks were released */
> > FI_ALIGNED_WRITE, /* enable aligned write */
> > + FI_COW_FILE, /* indicate COW file */
> > FI_MAX, /* max flag, never be used */
> > };
> >
> > @@ -3207,6 +3208,11 @@ static inline bool f2fs_is_atomic_file(struct inode *inode)
> > return is_inode_flag_set(inode, FI_ATOMIC_FILE);
> > }
> >
> > +static inline bool f2fs_is_cow_file(struct inode *inode)
> > +{
> > + return is_inode_flag_set(inode, FI_COW_FILE);
> > +}
> > +
> > static inline bool f2fs_is_first_block_written(struct inode *inode)
> > {
> > return is_inode_flag_set(inode, FI_FIRST_BLOCK_WRITTEN);
> > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > index a90184900698..973a479f9a3d 100644
> > --- a/fs/f2fs/file.c
> > +++ b/fs/f2fs/file.c
> > @@ -2062,7 +2062,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
> > spin_unlock(&sbi->inode_lock[ATOMIC_FILE]);
> >
> > set_inode_flag(inode, FI_ATOMIC_FILE);
> > - set_inode_flag(fi->cow_inode, FI_ATOMIC_FILE);
> > + set_inode_flag(fi->cow_inode, FI_COW_FILE);
> > clear_inode_flag(fi->cow_inode, FI_INLINE_DATA);
> > f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
> >
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index 44a04a832e24..6d5fc221ef35 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -193,7 +193,7 @@ void f2fs_abort_atomic_write(struct inode *inode, bool clean)
> > if (f2fs_is_atomic_file(inode)) {
> > if (clean)
> > truncate_inode_pages_final(inode->i_mapping);
> > - clear_inode_flag(fi->cow_inode, FI_ATOMIC_FILE);
> > + clear_inode_flag(fi->cow_inode, FI_COW_FILE);
> > iput(fi->cow_inode);
> > fi->cow_inode = NULL;
> > clear_inode_flag(inode, FI_ATOMIC_FILE);
> > @@ -3166,7 +3166,8 @@ static int __get_segment_type_6(struct f2fs_io_info *fio)
> > return CURSEG_COLD_DATA;
> > if (file_is_hot(inode) ||
> > is_inode_flag_set(inode, FI_HOT_DATA) ||
> > - f2fs_is_atomic_file(inode))
> > + f2fs_is_atomic_file(inode) ||
>
> I think we can remove f2fs_is_atomic_file(inode) now.

I removed it and applied the patch. :)
Thanks,

>
> > + f2fs_is_cow_file(inode))
> > return CURSEG_HOT_DATA;
> > return f2fs_rw_hint_to_seg_type(inode->i_write_hint);
> > } else {
> > --
> > 2.31.1
> >
> >
> >
> > _______________________________________________
> > Linux-f2fs-devel mailing list
> > [email protected]
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