On 2024/5/16 18:15, 孙士杰 wrote:
> I didn't get it, if there is no cp_err, f2fs_write_checkpoint() in
> f2fs_put_super() will flush all dirty pages of node_inode, if there is
> cp_err, below flow will keep all dirty pages being truncated, and
> there is sanity check on all types of dirty pages.
>
> ===》
> I understand what you mean, so is it better to modify in this way? Please help to check, thank you
Hi, let's figure out the root cause first?
Thanks,
>
> ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> *发件人:* sunshijie <[email protected]>
> *发送时间:* 2024年5月16日 18:13:38
> *收件人:* [email protected]; [email protected]; [email protected]; [email protected]
> *抄送:* 孙士杰
> *主题:* [External Mail][PATCH] f2fs: fix panic in f2fs_put_super
> [外部邮件] 此邮件来源于小米公司外部，请谨慎处理。若对邮件安全性存疑，请将邮件转发给[email protected]进行反馈
>
> When thread A calls kill_f2fs_super, Thread A first executes the code sbi->node_inode = NULL;
> Then thread A may submit a bio to the function iput(sbi->meta_inode);
> Then thread A enters the process D state,
> Now that the bio submitted by thread A is complete, it calls f2fs_write_end_io and may trigger null-ptr-deref in NODE_MAPPING.
>
> Thread A IRQ context
> - f2fs_put_super
> - sbi->node_inode = NULL;
> - iput(sbi->meta_inode);
> - iput_final
> - write_inode_now
> - writeback_single_inode
> - __writeback_single_inode
> - filemap_fdatawait
> - filemap_fdatawait_range
> - __kcfi_typeid_free_transhuge_page
> - __filemap_fdatawait_range
> - wait_on_page_writeback
> - folio_wait_writeback
> - folio_wait_bit
> - folio_wait_bit_common
> - io_schedule
>
> - __handle_irq_event_percpu
> - ufs_qcom_mcq_esi_handler
> - ufshcd_mcq_poll_cqe_nolock
> - ufshcd_compl_one_cqe
> - scsi_done
> - scsi_done_internal
> - blk_mq_complete_request
> - scsi_complete
> - scsi_finish_command
> - scsi_io_completion
> - scsi_end_request
> - blk_update_request
> - bio_endio
> - f2fs_write_end_io
> - NODE_MAPPING(sbi)
>
> Signed-off-by: sunshijie <[email protected]>
> ---
> fs/f2fs/super.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index adffc9b80a9c..62d4f229f601 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -1642,9 +1642,9 @@ static void f2fs_put_super(struct super_block *sb)
> f2fs_destroy_compress_inode(sbi);
>
> iput(sbi->node_inode);
> - sbi->node_inode = NULL;
> -
> iput(sbi->meta_inode);
> +
> + sbi->node_inode = NULL;
> sbi->meta_inode = NULL;
>
> mutex_unlock(&sbi->umount_mutex);
> --
> 2.34.1
>
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