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Chao Yu
a8933b6b68
As reported in bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204193 A null pointer dereference bug is triggered in f2fs under kernel-5.1.3. kasan_report.cold+0x5/0x32 f2fs_write_end_io+0x215/0x650 bio_endio+0x26e/0x320 blk_update_request+0x209/0x5d0 blk_mq_end_request+0x2e/0x230 lo_complete_rq+0x12c/0x190 blk_done_softirq+0x14a/0x1a0 __do_softirq+0x119/0x3e5 irq_exit+0x94/0xe0 call_function_single_interrupt+0xf/0x20 During umount, we will access NULL sbi->node_inode pointer in f2fs_write_end_io(): f2fs_bug_on(sbi, page->mapping == NODE_MAPPING(sbi) && page->index != nid_of_node(page)); The reason is if disable_checkpoint mount option is on, meta dirty pages can remain during umount, and then be flushed by iput() of meta_inode, however node_inode has been iput()ed before meta_inode's iput(). Since checkpoint is disabled, all meta/node datas are useless and should be dropped in next mount, so in umount, let's adjust drop_inode() to give a hint to iput_final() to drop all those dirty datas correctly. Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.