From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.13]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 512F83750D7; Mon, 20 Apr 2026 03:19:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.13 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776655145; cv=none; b=U1A98wZov7EwS7UW5GSuAmuwYQ2zx94usEkr/uI8rb2aVqzj1uh8/cPIpsSI8jhPF5cH0cjleD1jYNXoXuxeMhz68pN7T3YLLkIZDrkEZ9+4j1VEziKNfECol32Pi7Ovdgs13idPM3PehddN+0MS+pKxGIllkgler8pQwbdBcP8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776655145; c=relaxed/simple; bh=1bxUidDXnuX4Rrmsk0OJ2++qsMgWu032Ens3VIhCm0E=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=amOvOLCXwtIst2lcRscK2CTBEBjOSSO2r6ieLCBVa3smTbDseAMiH5TrEnAHXA+QiC+RBjgUC/TX/qbr0ruL2KWYk/bEeWv7Xm+sAkvJmNmD4/aorAgCxMRjn9X/G5rKsf6QUWAA7ws0SflO37c3nUMF8MuMgbXI0HQ281qKA8M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=cG512nBl; arc=none smtp.client-ip=192.198.163.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="cG512nBl" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1776655143; x=1808191143; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=1bxUidDXnuX4Rrmsk0OJ2++qsMgWu032Ens3VIhCm0E=; b=cG512nBlTGBKGiIqEM36lMUzau4VdDJtoayIz8T6qsWSTupqbagUZWHu ZScsqF+IBq35VrtxqRnEOPIZQwjhEgK4f2dsTc9zMnmymjb9dyeXyQFH1 QKIyiPPM1VnTbWbUJplHY+9AIQGVZAaHmgp8scjWAiOaFlkYvcgizDzjR p2XqUoahE7IPruxOBJrDa6yTk1WIzSt8tLQ0E1tptv4IZC7xYwwHzWfUd 1K980RlAuuHmpKgcO/Hwv5dsLaWdvk24hSC6gDmHspIgL8Hk0aqEwhCfA 0Re1ZXVp5oWwgRaeBIGldWjeVU2aXVipjOhMoVx/4ScFFqakWlukMRSgz w==; X-CSE-ConnectionGUID: Zrc9NWZ0RjGkgjYhJTm6vw== X-CSE-MsgGUID: nVG9Uwt+QgSKu5F2raEP2w== X-IronPort-AV: E=McAfee;i="6800,10657,11762"; a="80153592" X-IronPort-AV: E=Sophos;i="6.23,189,1770624000"; d="scan'208";a="80153592" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by fmvoesa107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Apr 2026 20:19:02 -0700 X-CSE-ConnectionGUID: oAjuM7i7ScaGz4zFrO+pgg== X-CSE-MsgGUID: E1jeWM3iRXqbP7yLfpKP3w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,189,1770624000"; d="scan'208";a="225097829" Received: from qat-server-366.sh.intel.com ([10.67.116.195]) by fmviesa009.fm.intel.com with ESMTP; 19 Apr 2026 20:19:00 -0700 From: Jie Wang To: agruenba@redhat.com, bigeasy@linutronix.de, clrkwllms@kernel.org, rostedt@goodmis.org Cc: gfs2@lists.linux.dev, linux-rt-devel@lists.linux.dev, Jie Wang , syzbot+642d0561f78362d67d3f@syzkaller.appspotmail.com Subject: [PATCH] gfs2: fix quota init duplicate scan Date: Mon, 20 Apr 2026 11:06:22 +0000 Message-Id: <20260420110622.9742-1-jie.wang@intel.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: gfs2@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit gfs2_quota_init() checks for duplicate quota_change IDs while holding qd_lock and the quota hash bucket bitlock. That path used gfs2_qd_search_bucket(), which takes a lockref reference via lockref_get_not_dead(). On PREEMPT_RT this may sleep, which is not allowed under the bucket bitlock, triggering "sleeping function called from invalid context". Use a no-ref bucket lookup in this path, then continue duplicate handling without taking a lockref there. Also save the current qc pointer before iterator advance, and clear that saved slot on duplicate so the correct on-disk entry is zeroed. This patch fixes a bug reported by syzbot. Reported-by: syzbot+642d0561f78362d67d3f@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=642d0561f78362d67d3f Tested-by: syzbot+642d0561f78362d67d3f@syzkaller.appspotmail.com Signed-off-by: Jie Wang --- fs/gfs2/quota.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-) diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c index 5290865f27f1..0191ba211670 100644 --- a/fs/gfs2/quota.c +++ b/fs/gfs2/quota.c @@ -275,6 +275,25 @@ static struct gfs2_quota_data *gfs2_qd_search_bucket(unsigned int hash, return NULL; } +/* + * Lookup variant for callers which already hold qd_lock + bucket lock. + */ +static struct gfs2_quota_data * +gfs2_qd_search_bucket_noref(unsigned int hash, const struct gfs2_sbd *sdp, struct kqid qid) +{ + struct gfs2_quota_data *qd; + struct hlist_bl_node *h; + + hlist_bl_for_each_entry_rcu(qd, h, &qd_hash_table[hash], qd_hlist) { + if (!qid_eq(qd->qd_id, qid)) + continue; + if (qd->qd_sbd == sdp) + return qd; + } + + return NULL; +} + static int qd_get(struct gfs2_sbd *sdp, struct kqid qid, struct gfs2_quota_data **qdp) @@ -1435,6 +1454,7 @@ int gfs2_quota_init(struct gfs2_sbd *sdp) for (y = 0; y < sdp->sd_qc_per_block && slot < sdp->sd_quota_slots; y++, slot++) { struct gfs2_quota_data *old_qd, *qd; + struct gfs2_quota_change *dup_qc = qc; s64 qc_change = be64_to_cpu(qc->qc_change); u32 qc_flags = be32_to_cpu(qc->qc_flags); enum quota_type qtype = (qc_flags & GFS2_QCF_USER) ? @@ -1458,23 +1478,22 @@ int gfs2_quota_init(struct gfs2_sbd *sdp) spin_lock(&qd_lock); spin_lock_bucket(hash); - old_qd = gfs2_qd_search_bucket(hash, sdp, qc_id); + old_qd = gfs2_qd_search_bucket_noref(hash, sdp, qc_id); + spin_unlock_bucket(hash); if (old_qd) { fs_err(sdp, "Corruption found in quota_change%u" "file: duplicate identifier in " "slot %u\n", sdp->sd_jdesc->jd_jid, slot); - spin_unlock_bucket(hash); spin_unlock(&qd_lock); - qd_put(old_qd); gfs2_glock_put(qd->qd_gl); kmem_cache_free(gfs2_quotad_cachep, qd); /* zero out the duplicate slot */ lock_buffer(bh); - memset(qc, 0, sizeof(*qc)); + memset(dup_qc, 0, sizeof(*dup_qc)); mark_buffer_dirty(bh); unlock_buffer(bh); @@ -1483,6 +1502,7 @@ int gfs2_quota_init(struct gfs2_sbd *sdp) BUG_ON(test_and_set_bit(slot, sdp->sd_quota_bitmap)); list_add(&qd->qd_list, &sdp->sd_quota_list); atomic_inc(&sdp->sd_quota_count); + spin_lock_bucket(hash); hlist_bl_add_head_rcu(&qd->qd_hlist, &qd_hash_table[hash]); spin_unlock_bucket(hash); spin_unlock(&qd_lock); -- 2.34.1