This is a note to let you know that I've just added the patch titled
fuse: release pipe buf after last use
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fuse-release-pipe-buf-after-last-use.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 473441720c8616dfaf4451f9c7ea14f0eb5e5d65 Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Date: Thu, 25 Nov 2021 14:05:18 +0100
Subject: fuse: release pipe buf after last use
From: Miklos Szeredi <mszeredi@xxxxxxxxxx>
commit 473441720c8616dfaf4451f9c7ea14f0eb5e5d65 upstream.
Checking buf->flags should be done before the pipe_buf_release() is called
on the pipe buffer, since releasing the buffer might modify the flags.
This is exactly what page_cache_pipe_buf_release() does, and which results
in the same VM_BUG_ON_PAGE(PageLRU(page)) that the original patch was
trying to fix.
Reported-by: Justin Forbes <jmforbes@xxxxxxxxxxx>
Fixes: 712a951025c0 ("fuse: fix page stealing")
Cc: <stable@xxxxxxxxxxxxxxx> # v2.6.35
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/fuse/dev.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -903,6 +903,11 @@ static int fuse_try_move_page(struct fus
if (fuse_check_page(newpage) != 0)
goto out_fallback_unlock;
+ page_cache_get(newpage);
+
+ if (!(buf->flags & PIPE_BUF_FLAG_LRU))
+ lru_cache_add_file(newpage);
+
/*
* This is a new and locked page, it shouldn't be mapped or
* have any special flags on it
@@ -922,11 +927,6 @@ static int fuse_try_move_page(struct fus
return err;
}
- page_cache_get(newpage);
-
- if (!(buf->flags & PIPE_BUF_FLAG_LRU))
- lru_cache_add_file(newpage);
-
err = 0;
spin_lock(&cs->req->waitq.lock);
if (test_bit(FR_ABORTED, &cs->req->flags))
Patches currently in stable-queue which might be from mszeredi@xxxxxxxxxx are
queue-4.4/fuse-release-pipe-buf-after-last-use.patch
