From: Baokun Li <libaokun@linux.alibaba.com> mainline inclusion from mainline-v7.3-rc1 commit a927f1867e61b78f39f9da0bbba3c98c2ca151fe category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18697 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- fuse_open() takes filemap_invalidate_lock() for a DAX truncate (dax_truncate = true) and releases it before the out_inode_unlock label. But when fuse_dax_break_layouts() fails, the goto out_inode_unlock skips the unlock and leaks the rwsem, so any later fault or truncate on the file stalls on the stale lock. fuse_dax_break_layouts() can fail with -ERESTARTSYS when a signal interrupts the wait for busy DAX pages to drain: open("file", O_RDWR | O_TRUNC) └─ fuse_open() ├─ filemap_invalidate_lock() # dax_truncate └─ fuse_dax_break_layouts() └─ dax_break_layout() └─ wait_page_idle() # TASK_INTERRUPTIBLE └─ fuse_wait_dax_page() # unlock, schedule, re-lock └─ signal → -ERESTARTSYS goto out_inode_unlock # <- lock leaked Fix this by moving filemap_invalidate_unlock() below the label so that all error paths release the lock, and rename the label to out_unlock as it now covers more than just the inode lock. Fixes: 2fdbb8dd0155 ("fuse: fix deadlock between atomic O_TRUNC and page invalidation") Cc: stable@vger.kernel.org # v6.0+ Signed-off-by: Baokun Li <libaokun@linux.alibaba.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Conflicts: fs/fuse/file.c [The target tree still uses i_mmap_sem instead of filemap_invalidate_lock(), so relocate up_write(&i_mmap_sem) below the renamed out_unlock label.] Signed-off-by: Yang Erkun <yangerkun@huawei.com> --- fs/fuse/file.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 87c8272d0e17..91fb1f67d6af 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -245,7 +245,7 @@ int fuse_open_common(struct inode *inode, struct file *file, bool isdir) down_write(&get_fuse_inode(inode)->i_mmap_sem); err = fuse_dax_break_layouts(inode, 0, 0); if (err) - goto out_inode_unlock; + goto out_unlock; } if (is_wb_truncate || dax_truncate) @@ -265,10 +265,10 @@ int fuse_open_common(struct inode *inode, struct file *file, bool isdir) else if (!(ff->open_flags & FOPEN_KEEP_CACHE)) invalidate_inode_pages2(inode->i_mapping); } +out_unlock: if (dax_truncate) up_write(&get_fuse_inode(inode)->i_mmap_sem); -out_inode_unlock: if (is_wb_truncate || dax_truncate) inode_unlock(inode); -- 2.52.0