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7bf1823e01
syzbot has found a possible deadlock in ocfs2_get_system_file_inode [1].
The scenario is depicted here,
CPU0 CPU1
lock(&ocfs2_file_ip_alloc_sem_key);
lock(&osb->system_file_mutex);
lock(&ocfs2_file_ip_alloc_sem_key);
lock(&osb->system_file_mutex);
The function calls which could lead to this are:
CPU0
ocfs2_mknod - lock(&ocfs2_file_ip_alloc_sem_key);
.
.
.
ocfs2_get_system_file_inode - lock(&osb->system_file_mutex);
CPU1 -
ocfs2_fill_super - lock(&osb->system_file_mutex);
.
.
.
ocfs2_read_virt_blocks - lock(&ocfs2_file_ip_alloc_sem_key);
This issue can be resolved by making the down_read -> down_read_try
in the ocfs2_read_virt_blocks.
[1] https://syzkaller.appspot.com/bug?extid=e0055ea09f1f5e6fabdd
Link: https://lkml.kernel.org/r/20240924093257.7181-1-pvmohammedanees2003@gmail.com
Signed-off-by: Mohammed Anees <pvmohammedanees2003@gmail.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reported-by: <syzbot+e0055ea09f1f5e6fabdd@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=e0055ea09f1f5e6fabdd
Tested-by: syzbot+e0055ea09f1f5e6fabdd@syzkaller.appspotmail.com
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.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 reStructuredText 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.