ocfs2: fix deadlock in ocfs2_get_system_file_inode
commit 7bf1823e010e8db2fb649c790bd1b449a75f52d8 upstream. 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> Cc: Xingyu Li <xli399@ucr.edu> Cc: Zheng Zhang <zzhan173@ucr.edu> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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