On Tue, Jul 12, 2022 at 11:50:26AM -0700, Tadeusz Struk wrote:
> From: Baokun Li <libaokun1@xxxxxxxxxx>
>
> This is backport to 5.10 stable kernel only.
> This patch has already been applied to kernels > 5.10.
>
> commit f87c7a4b084afc13190cbb263538e444cb2b392a upstream
>
> Hulk Robot reported a BUG_ON:
> ==================================================================
> EXT4-fs error (device loop3): ext4_mb_generate_buddy:805: group 0,
> block bitmap and bg descriptor inconsistent: 25 vs 31513 free clusters
> kernel BUG at fs/ext4/ext4_jbd2.c:53!
> invalid opcode: 0000 [#1] SMP KASAN PTI
> CPU: 0 PID: 25371 Comm: syz-executor.3 Not tainted 5.10.0+ #1
> RIP: 0010:ext4_put_nojournal fs/ext4/ext4_jbd2.c:53 [inline]
> RIP: 0010:__ext4_journal_stop+0x10e/0x110 fs/ext4/ext4_jbd2.c:116
> [...]
> Call Trace:
> ext4_write_inline_data_end+0x59a/0x730 fs/ext4/inline.c:795
> generic_perform_write+0x279/0x3c0 mm/filemap.c:3344
> ext4_buffered_write_iter+0x2e3/0x3d0 fs/ext4/file.c:270
> ext4_file_write_iter+0x30a/0x11c0 fs/ext4/file.c:520
> do_iter_readv_writev+0x339/0x3c0 fs/read_write.c:732
> do_iter_write+0x107/0x430 fs/read_write.c:861
> vfs_writev fs/read_write.c:934 [inline]
> do_pwritev+0x1e5/0x380 fs/read_write.c:1031
> [...]
> ==================================================================
>
> Above issue may happen as follows:
> cpu1 cpu2
> __________________________|__________________________
> do_pwritev
> vfs_writev
> do_iter_write
> ext4_file_write_iter
> ext4_buffered_write_iter
> generic_perform_write
> ext4_da_write_begin
> vfs_fallocate
> ext4_fallocate
> ext4_convert_inline_data
> ext4_convert_inline_data_nolock
> ext4_destroy_inline_data_nolock
> clear EXT4_STATE_MAY_INLINE_DATA
> ext4_map_blocks
> ext4_ext_map_blocks
> ext4_mb_new_blocks
> ext4_mb_regular_allocator
> ext4_mb_good_group_nolock
> ext4_mb_init_group
> ext4_mb_init_cache
> ext4_mb_generate_buddy --> error
> ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)
> ext4_restore_inline_data
> set EXT4_STATE_MAY_INLINE_DATA
> ext4_block_write_begin
> ext4_da_write_end
> ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)
> ext4_write_inline_data_end
> handle=NULL
> ext4_journal_stop(handle)
> __ext4_journal_stop
> ext4_put_nojournal(handle)
> ref_cnt = (unsigned long)handle
> BUG_ON(ref_cnt == 0) ---> BUG_ON
>
> The lock held by ext4_convert_inline_data is xattr_sem, but the lock
> held by generic_perform_write is i_rwsem. Therefore, the two locks can
> be concurrent.
>
> To solve above issue, we add inode_lock() for ext4_convert_inline_data().
> At the same time, move ext4_convert_inline_data() in front of
> ext4_punch_hole(), remove similar handling from ext4_punch_hole().
>
> Fixes: 0c8d414f163f ("ext4: let fallocate handle inline data correctly")
> Cc: stable@xxxxxxxxxxxxxxx
> Reported-by: syzbot+2cc95c8e803bc7c9e5cb@xxxxxxxxxxxxxxxxxxxxxxxxx
> Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> Signed-off-by: Baokun Li <libaokun1@xxxxxxxxxx>
> Reviewed-by: Jan Kara <jack@xxxxxxx>
> Link: https://syzkaller.appspot.com/bug?id=184195865fd95e1e551f8af0fe43858126d15076
> Link: https://lore.kernel.org/r/20220428134031.4153381-1-libaokun1@xxxxxxxxxx
> Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
> Signed-off-by: Tadeusz Struk <tadeusz.struk@xxxxxxxxxx>
> ---
> fs/ext4/extents.c | 9 +++++----
> fs/ext4/inode.c | 9 ---------
> 2 files changed, 5 insertions(+), 13 deletions(-)
Both now queued up, thanks.
greg k-h
