250dbf5151
Thread A Thread B - f2fs_remount - stop_gc_thread - f2fs_sbi_store sbi->gc_thread = NULL; access sbi->gc_thread->gc_* Previously, we allocate memory for sbi->gc_thread based on background gc thread mount option, the memory can be released if we turn off that mount option, but still there are several places access gc_thread pointer without considering race condition, result in NULL point dereference. In order to fix this issue, use sb->s_umount to exclude those operations. 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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.