From nobody Thu Apr 9 17:57:45 2026 Received: from mail-oo1-f70.google.com (mail-oo1-f70.google.com [209.85.161.70]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 83C511C4A20 for ; Fri, 6 Mar 2026 09:16:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.70 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772788585; cv=none; b=FH1OD9QbeGWYfZIwQkF7VSrbPrpbRjnjYVPxcivORwwYNMKQy/sHotV/UCuGvFAYny4B9IAoyOKYI3WRwhl0IvhafXSRvA1Gw6WJD9vPqvclr2JZPDu9ehF//GiKk7J8THTDvkelKQxBDjvcdUYCFThoX7h4cR9UzGK0L4OW3l4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772788585; c=relaxed/simple; bh=VSoRfBvKV7khrobN8/uFw9+VCXmcrqvk36adVEJEo+o=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=nmRs58MJ1wEuZPBbgIouWNu0Rvtjl8VCJobAAwUYbK9Rn/j4HU+cUpfCdVzknSQvTKf8cIl8iTlg235nNHM/K6x2vygjdgCbDk9lWqHpZkbUTSbsjtlMpgnKw89bFXcn9QZQk+W2zU2oaLjRPbOO4w+PL5DxRt3P8apjbZnK2c0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.70 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f70.google.com with SMTP id 006d021491bc7-679c5ed0942so105090910eaf.1 for ; Fri, 06 Mar 2026 01:16:23 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772788582; x=1773393382; h=to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=KyuDtxB6oxI4wl4b1fTqtEg82McEJnfcb8KA6ZYSfcQ=; b=etSgWrkbywyWS2IueC6hqZQq41qwx/v2e48FAM7MjzE/V9ROCOoQXW/chSBXL2POq1 9LHlH00hUeeNRh3oRtRgC7ZIyZ7fynEZG63r0sVsVrsUum6yk5s94P5Y3TF5HVJbfod5 uLu7kxVjiUS/pOQmenglmKxrQg9rsBnDO+3o02/cCEFxfqh9ZE3y3k3jIDFtgO3tkZNs /kF+uk3z+P2wA2wa6Mwfbs1VhWmb/zlNhUH9l0DGnl8qDXazPue18uvqYs/sn4UAAo8i J38CS8C3OLgypMXuyJSv2ime+7CeALXfl9ee4qmEclFjN7sgaRVI/WJkgwcM/EQo/ZuJ e18A== X-Gm-Message-State: AOJu0Yy70K0iqXBeL9v9XD9IgdmqGKMjc+kJlo7MvGzsLKaWdbtgEGcg eAlwWOFoqvFnRJ1Y9SNWByUbvzRKL+q+9wCJxA2PwXvmyV8c+r53GUTEweRECnB5rDz+Uuz2dE3 tBEU44jGEW11XMJdU0gXtU+X3KIlwy2rt5UQai1/KmXd69iKLP5wXngw09iQ= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:f024:b0:676:e8d1:bb55 with SMTP id 006d021491bc7-67b9bd51db3mr874084eaf.59.1772788582481; Fri, 06 Mar 2026 01:16:22 -0800 (PST) Date: Fri, 06 Mar 2026 01:16:22 -0800 In-Reply-To: <69a9251d.a70a0220.2f119.0003.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69aa9b66.050a0220.13f275.0016.GAE@google.com> Subject: Forwarded: [PATCH] gfs2: add debug printk to trace existing entry in gfs2_create_inode From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" For archival purposes, forwarding an incoming command email to linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com. *** Subject: [PATCH] gfs2: add debug printk to trace existing entry in gfs2_cre= ate_inode Author: kartikey406@gmail.com #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git= master Add a debug printk when gfs2_dir_search finds an existing entry in gfs2_create_inode. This helps confirm whether the rwsem unlock WARNING in filename_symlinkat is caused by gfs2_create_inode returning false success (0) when file is NULL and an existing entry is found on a corrupted GFS2 image. The printk logs the directory inode, creation mode, file pointer, found inode, and rwsem owner at the point where the existing entry is detected. This is a temporary diagnostic patch and should be reverted once the root cause is confirmed. Reported-by: syzbot+2ed46b6b748df855347f@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3D2ed46b6b748df855347f Signed-off-by: Deepanshu Kartikey --- fs/gfs2/inode.c | 13 +++++++++++++ fs/namei.c | 30 ++++++++++++++++++++++++++++-- 2 files changed, 41 insertions(+), 2 deletions(-) diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c index 8344040ecaf7..9a3df067bea6 100644 --- a/fs/gfs2/inode.c +++ b/fs/gfs2/inode.c @@ -725,6 +725,8 @@ static int gfs2_create_inode(struct inode *dir, struct = dentry *dentry, error =3D gfs2_rindex_update(sdp); if (error) goto fail; + pr_warn("DEBUG GFS2: after glock_nq dir=3D%px rwsem owner=3D%px current= =3D%px\n", + dir, READ_ONCE(dir->i_rwsem.owner), current); =20 error =3D gfs2_glock_nq_init(dip->i_gl, LM_ST_EXCLUSIVE, 0, &d_gh); if (error) @@ -738,6 +740,9 @@ static int gfs2_create_inode(struct inode *dir, struct = dentry *dentry, inode =3D gfs2_dir_search(dir, &dentry->d_name, !S_ISREG(mode) || excl); error =3D PTR_ERR(inode); if (!IS_ERR(inode)) { + pr_warn("DEBUG GFS2: gfs2_create_inode found existing entry! dir=3D%px m= ode=3D%o file=3D%px inode=3D%px S_ISDIR=3D%d rwsem owner=3D%px current=3D%p= x\n", + dir, mode, file, inode, S_ISDIR(inode->i_mode), + READ_ONCE(dir->i_rwsem.owner), current); if (S_ISDIR(inode->i_mode)) { iput(inode); inode =3D NULL; @@ -893,6 +898,8 @@ static int gfs2_create_inode(struct inode *dir, struct = dentry *dentry, =20 mark_inode_dirty(inode); d_instantiate(dentry, inode); + pr_warn("DEBUG GFS2: before glock_dq dir=3D%px rwsem owner=3D%px current= =3D%px\n", + dir, READ_ONCE(dir->i_rwsem.owner), current); /* After instantiate, errors should result in evict which will destroy * both inode and iopen glocks properly. */ if (file) { @@ -900,6 +907,8 @@ static int gfs2_create_inode(struct inode *dir, struct = dentry *dentry, error =3D finish_open(file, dentry, gfs2_open_common); } gfs2_glock_dq_uninit(&d_gh); + pr_warn("DEBUG GFS2: after glock_dq dir=3D%px rwsem owner=3D%px current= =3D%px\n", + dir, READ_ONCE(dir->i_rwsem.owner), current); gfs2_qa_put(ip); gfs2_glock_dq_uninit(&gh); gfs2_glock_put(io_gl); @@ -937,7 +946,11 @@ static int gfs2_create_inode(struct inode *dir, struct= dentry *dentry, posix_acl_release(acl); fail_gunlock: gfs2_dir_no_add(&da); + pr_warn("DEBUG GFS2: fail_gunlock before glock_dq dir=3D%px rwsem owner= =3D%px current=3D%px error=3D%d\n", + dir, READ_ONCE(dir->i_rwsem.owner), current, error); gfs2_glock_dq_uninit(&d_gh); + pr_warn("DEBUG GFS2: fail_gunlock after glock_dq dir=3D%px rwsem owner=3D= %px current=3D%px\n", + dir, READ_ONCE(dir->i_rwsem.owner), current); if (!IS_ERR_OR_NULL(inode)) { if (inode_state_read_once(inode) & I_NEW) iget_failed(inode); diff --git a/fs/namei.c b/fs/namei.c index 58f715f7657e..768944691e24 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2922,7 +2922,13 @@ static struct dentry *__start_dirop(struct dentry *p= arent, struct qstr *name, } else { inode_lock_nested(dir, I_MUTEX_PARENT); } + pr_warn("DEBUG LOCK: __start_dirop locked dir=3D%px count=3D%ld owner=3D%= px current=3D%px\n", + dir, atomic_long_read(&dir->i_rwsem.count), + READ_ONCE(dir->i_rwsem.owner), current); dentry =3D lookup_one_qstr_excl(name, parent, lookup_flags); + pr_warn("DEBUG LOCK: __start_dirop after lookup dir=3D%px count=3D%ld own= er=3D%px current=3D%px dentry_err=3D%d\n", + dir, atomic_long_read(&dir->i_rwsem.count), + READ_ONCE(dir->i_rwsem.owner), current, IS_ERR(dentry)); if (IS_ERR(dentry)) inode_unlock(dir); return dentry; @@ -2944,6 +2950,11 @@ struct dentry *start_dirop(struct dentry *parent, st= ruct qstr *name, void end_dirop(struct dentry *de) { if (!IS_ERR(de)) { + struct inode *dir =3D d_inode(de->d_parent); + pr_warn("DEBUG: end_dirop: de=3D%px parent=3D%px inode=3D%px rwsem count= =3D%ld owner=3D%px current=3D%px\n", + de, de->d_parent, dir, + atomic_long_read(&dir->i_rwsem.count), + READ_ONCE(dir->i_rwsem.owner), current); inode_unlock(de->d_parent->d_inode); dput(de); } @@ -4922,7 +4933,9 @@ static struct dentry *filename_create(int dfd, struct= filename *name, dentry =3D start_dirop(path->dentry, &last, reval_flag | create_flags); if (IS_ERR(dentry)) goto out_drop_write; - + pr_warn("DEBUG: after start_dirop: dentry=3D%px parent=3D%px parent_inode= =3D%px rwsem owner=3D%px current=3D%px\n", + dentry, dentry->d_parent, d_inode(dentry->d_parent), + (void *)atomic_long_read(&d_inode(dentry->d_parent)->i_rwsem.count), cur= rent); if (unlikely(error)) goto fail; =20 @@ -4959,7 +4972,10 @@ EXPORT_SYMBOL(start_creating_path); */ void end_creating_path(const struct path *path, struct dentry *dentry) { - end_creating(dentry); + if (!IS_ERR(dentry)) { + inode_unlock(d_inode(path->dentry)); + dput(dentry); + } mnt_drop_write(path->mnt); path_put(path); } @@ -5595,6 +5611,9 @@ int vfs_symlink(struct mnt_idmap *idmap, struct inode= *dir, struct dentry *dentry, const char *oldname, struct delegated_inode *delegated_inode) { + pr_warn("DEBUG VFS: before symlink: dir=3D%px sb_type=3D%s symlink_fn=3D%= ps rwsem owner=3D%px current=3D%px\n", + dir, dir->i_sb->s_type->name, dir->i_op->symlink, + READ_ONCE(dir->i_rwsem.owner), current); int error; =20 error =3D may_create_dentry(idmap, dir, dentry); @@ -5613,6 +5632,9 @@ int vfs_symlink(struct mnt_idmap *idmap, struct inode= *dir, return error; =20 error =3D dir->i_op->symlink(idmap, dir, dentry, oldname); + pr_warn("DEBUG VFS: after symlink: dir=3D%px sb_type=3D%s error=3D%d rwse= m owner=3D%px current=3D%px\n", + dir, dir->i_sb->s_type->name, error, + READ_ONCE(dir->i_rwsem.owner), current); if (!error) fsnotify_create(dir, dentry); return error; @@ -5639,6 +5661,10 @@ int filename_symlinkat(struct filename *from, int ne= wdfd, struct filename *to) if (!error) error =3D vfs_symlink(mnt_idmap(path.mnt), path.dentry->d_inode, dentry, from->name, &delegated_inode); + pr_warn("DEBUG: after vfs_symlink: error=3D%d dentry=3D%px parent=3D%px p= arent_inode=3D%px rwsem owner=3D%px path_dentry=3D%px path_inode=3D%px\n", + error, dentry, dentry->d_parent, d_inode(dentry->d_parent), + (void *)atomic_long_read(&d_inode(path.dentry)->i_rwsem.count), + path.dentry, d_inode(path.dentry)); end_creating_path(&path, dentry); if (is_delegated(&delegated_inode)) { error =3D break_deleg_wait(&delegated_inode); --=20 2.43.0