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([58.186.69.27]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3a9ff5b3b06sm421884a91.15.2026.10.07.10.33.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Oct 2026 10:33:29 -0700 (PDT) From: Bui Viet Dung To: Tejun Heo , Lai Jiangshan Cc: Mike Snitzer , Trond Myklebust , linux-kernel@vger.kernel.org, Bui Viet Dung , stable@vger.kernel.org Subject: [PATCH] workqueue: Fix NULL current_pwq deref in current_is_workqueue_mem_reclaim() Date: Thu, 8 Oct 2026 00:33:24 +0700 Message-ID: <20261007173324.227988-1-dungvn2345@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit current_wq_worker() indicates that %current is a kworker thread, but it does not guarantee that the worker is currently executing a work item, as worker->current_pwq is populated only while process_one_work() is actively running the work function. Outside of that window (e.g. during worker idle, initialization, or auxiliary execution paths), worker->current_pwq is NULL. In current_is_workqueue_mem_reclaim(), worker->current_pwq->wq is dereferenced without checking worker->current_pwq: return worker && ((worker->current_pwq->wq->flags & (WQ_MEM_RECLAIM | __WQ_LEGACY)) == WQ_MEM_RECLAIM); If current_is_workqueue_mem_reclaim() is called when worker->current_pwq is NULL, the kernel triggers a NULL pointer dereference. This mirrors the issue recently fixed in is_chained_work() by commit 980db94e3eee ("workqueue: Fix NULL current_pwq deref in chained work check"). Guard the check with worker->current_pwq before dereferencing ->wq. Fixes: da729ddd4a1b ("NFS/localio: issue IO inline when not in a memory-reclaim context") Cc: stable@vger.kernel.org Signed-off-by: Bui Viet Dung --- kernel/workqueue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index c56c042d1c3..c1cb328bce3 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -6320,7 +6320,7 @@ bool current_is_workqueue_mem_reclaim(void) { struct worker *worker = current_wq_worker(); - return worker && + return worker && worker->current_pwq && ((worker->current_pwq->wq->flags & (WQ_MEM_RECLAIM | __WQ_LEGACY)) == WQ_MEM_RECLAIM); } -- 2.43.0