From: Pan Bian <bianpan2016@xxxxxxx> [ Upstream commit 164f7e586739d07eb56af6f6d66acebb11f315c8 ] ocfs2_get_dentry() calls iput(inode) to drop the reference count of inode, and if the reference count hits 0, inode is freed. However, in this function, it then reads inode->i_generation, which may result in a use after free bug. Move the put operation later. Link: http://lkml.kernel.org/r/1543109237-110227-1-git-send-email-bianpan2016@xxxxxxx Fixes: 781f200cb7a("ocfs2: Remove masklog ML_EXPORT.") Signed-off-by: Pan Bian <bianpan2016@xxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Mark Fasheh <mark@xxxxxxxxxx> Cc: Joel Becker <jlbec@xxxxxxxxxxxx> Cc: Junxiao Bi <junxiao.bi@xxxxxxxxxx> Cc: Joseph Qi <jiangqi903@xxxxxxxxx> Cc: Changwei Ge <ge.changwei@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- fs/ocfs2/export.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ocfs2/export.c b/fs/ocfs2/export.c index 827fc9809bc2..3494e220b510 100644 --- a/fs/ocfs2/export.c +++ b/fs/ocfs2/export.c @@ -125,10 +125,10 @@ static struct dentry *ocfs2_get_dentry(struct super_block *sb, check_gen: if (handle->ih_generation != inode->i_generation) { - iput(inode); trace_ocfs2_get_dentry_generation((unsigned long long)blkno, handle->ih_generation, inode->i_generation); + iput(inode); result = ERR_PTR(-ESTALE); goto bail; } -- 2.17.1
