linux-kernel - Re: [syzbot] [v9fs?] WARNING in v9fs_begin

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <tencent_234974A3B3644C9769777466C1F365636505@qq.com>
Date: Sat, 10 Aug 2024 08:54:39 +0800
From: Edward Adam Davis <eadavis@...com>
To: syzbot+0b74d367d6e80661d6df@...kaller.appspotmail.com
Cc: linux-kernel@...r.kernel.org,
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [v9fs?] WARNING in v9fs_begin_writeback

debug

#syz test: upstream c0ecd6388360

diff --git a/fs/9p/fid.c b/fs/9p/fid.c
index de009a33e0e2..b5ccab74bb6f 100644
--- a/fs/9p/fid.c
+++ b/fs/9p/fid.c
@@ -13,6 +13,7 @@
 #include <linux/sched.h>
 #include <net/9p/9p.h>
 #include <net/9p/client.h>
+#include <linux/file.h>
 
 #include "v9fs.h"
 #include "v9fs_vfs.h"
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index a97ceb105cd8..7768cc70439d 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -34,6 +34,7 @@ static void v9fs_begin_writeback(struct netfs_io_request *wreq)
 {
 	struct p9_fid *fid;
 
+	printk("ino: %lx, %s\n", wreq->inode->i_ino, __func__);
 	fid = v9fs_fid_find_inode(wreq->inode, true, INVALID_UID, true);
 	if (!fid) {
 		WARN_ONCE(1, "folio expected an open fid inode->i_ino=%lx\n",
diff --git a/fs/9p/vfs_dir.c b/fs/9p/vfs_dir.c
index e0d34e4e9076..0ce9ab0d9a9d 100644
--- a/fs/9p/vfs_dir.c
+++ b/fs/9p/vfs_dir.c
@@ -219,6 +219,15 @@ int v9fs_dir_release(struct inode *inode, struct file *filp)
 			retval = filemap_fdatawrite(inode->i_mapping);
 
 		spin_lock(&inode->i_lock);
+		printk("del, ino: %lx, ino sync: %d, %s\n", inode->i_ino, inode->i_state & I_SYNC, __func__);
+		if (I_SYNC & inode->i_state) {
+			spin_unlock(&inode->i_lock);
+			if (wait_on_bit_timeout(&inode->i_state, I_SYNC,
+						TASK_UNINTERRUPTIBLE, 5 * HZ))
+				return -EBUSY;
+			spin_lock(&inode->i_lock);
+		}
+
 		hlist_del(&fid->ilist);
 		spin_unlock(&inode->i_lock);
 		put_err = p9_fid_put(fid);
diff --git a/fs/netfs/write_issue.c b/fs/netfs/write_issue.c
index 9258d30cffe3..60472069907e 100644
--- a/fs/netfs/write_issue.c
+++ b/fs/netfs/write_issue.c
@@ -502,6 +502,7 @@ int netfs_writepages(struct address_space *mapping,
 	struct netfs_io_request *wreq = NULL;
 	struct folio *folio;
 	int error = 0;
+	static DEFINE_MUTEX(wlock);
 
 	if (wbc->sync_mode == WB_SYNC_ALL)
 		mutex_lock(&ictx->wb_lock);
@@ -522,12 +523,18 @@ int netfs_writepages(struct address_space *mapping,
 	trace_netfs_write(wreq, netfs_write_trace_writeback);
 	netfs_stat(&netfs_n_wh_writepages);
 
+	printk("sync: %d, tb-sync: %d, ino: %lx, %s\n", wreq->inode->i_state & I_SYNC,
+			test_bit(I_SYNC, &wreq->inode->i_state),
+			wreq->inode->i_ino, __func__);
+	mutex_lock(&wlock);
+	wreq->inode->i_state |= I_SYNC;
 	do {
 		_debug("wbiter %lx %llx", folio->index, wreq->start + wreq->submitted);
 
 		/* It appears we don't have to handle cyclic writeback wrapping. */
 		WARN_ON_ONCE(wreq && folio_pos(folio) < wreq->start + wreq->submitted);
 
+		printk("ino: %lx, folio: %p, %s\n", wreq->inode->i_ino, folio, __func__);
 		if (netfs_folio_group(folio) != NETFS_FOLIO_COPY_TO_CACHE &&
 		    unlikely(!test_bit(NETFS_RREQ_UPLOAD_TO_SERVER, &wreq->flags))) {
 			set_bit(NETFS_RREQ_UPLOAD_TO_SERVER, &wreq->flags);
@@ -538,6 +545,8 @@ int netfs_writepages(struct address_space *mapping,
 		if (error < 0)
 			break;
 	} while ((folio = writeback_iter(mapping, wbc, folio, &error)));
+	wreq->inode->i_state &= ~I_SYNC;
+	mutex_unlock(&wlock);
 
 	for (int s = 0; s < NR_IO_STREAMS; s++)
 		netfs_issue_write(wreq, &wreq->io_streams[s]);