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Thu, 24 Sep 2026 01:20:35 +0800 (CST) From: Xiaochuan Li To: Jens Axboe Cc: io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, Sebastian Andrzej Siewior , Xiaochuan Li Subject: [PATCH v3] io_uring/lock: Keep spinlock release before wake_up() Date: Thu, 24 Sep 2026 01:20:32 +0800 Message-ID: <20260923172032.11057-1-chuanx2070@163.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260923164849.135000-1-chuanx2070@163.com> References: <20260923164849.135000-1-chuanx2070@163.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wDnz0NjCrRqQKRpAQ--.63117S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxXF18GFWDCFyUKryUZF45trb_yoW5CrW3pF W3K34rtFW8XFyq93y7AF1jy342kw4qgw48Grs5G34rArW5XrnIva1ktF4F9F45WrZ7Cry5 uF48trWa9a18ZwUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07U9_-QUUUUU= X-CM-SenderInfo: pfkxt0j0sqlii6rwjhhfrp/xtbC7gRjRmq0CmSFlQAA3v Content-Type: text/plain; charset="utf-8" When CONFIG_PREEMPT_RT enable, raw_spin_lock() will preempt_disable() -> raw_spin_lock() -> wake_up() ... -> spin_lock_irqsave() which will trigger: BUG: sleeping function called from invalid context at kernel/locking/spinlo= ck_rt.c:46 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 985654, name: iou-wr= k-983605 preempt_count: 1, expected: 0 RCU nest depth: 0, expected: 0 CPU: 3 PID: 985654 Comm: iou-wrk-983605 Tainted: G O 6.1.83-rt28-g1= 9631eb82f21 stack:0 ppid:977479 flags:0x00000008 tgid:977553 prio:120 preempt:0x100000001 rcu_read_lock_nesting:0 used_cpu 3 wake_cpu 3 on_cpu 3 on_rq 1 migrate_dis 0 arrive:17423426040675 queued:0 prev_sum:33955300 sum_exec:33955300 Call trace: dump_backtrace.part.0+0xdc/0xec show_stack+0x1c/0x30 dump_stack_lvl+0xac/0xc4 dump_stack+0x14/0x30 __might_resched+0x13c/0x170 rt_spin_lock+0x34/0xc0 __wake_up_common_lock+0x68/0xd0 __wake_up+0x1c/0x24 io_worker_handle_work+0x5b0/0x600 io_wqe_worker+0xf4/0x310 ret_from_fork+0x10/0x20 Signed-off-by: Xiaochuan Li --- Changes in v3: - Defer wake_up() after releasing acct->lock, add need_wake flag - keep need_wake from wq_has_sleeper() in the same order The v1 patch didn't show up on lore.kernel.org Link: [https://lore.kernel.org/io-uring/20260923164849.135000-1-chuanx2070@= 163.com/T/#t] io_uring/io-wq.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/io_uring/io-wq.c b/io_uring/io-wq.c index 2ca223e47d41..2dadde0ca395 100644 --- a/io_uring/io-wq.c +++ b/io_uring/io-wq.c @@ -526,7 +526,8 @@ static bool io_wait_on_hash(struct io_wq *wq, unsigned = int hash) } =20 static struct io_wq_work *io_get_next_work(struct io_wq_acct *acct, - struct io_wq *wq) + struct io_wq *wq, + bool *need_wake) __must_hold(acct->lock) { struct io_wq_work_node *node, *prev; @@ -575,8 +576,7 @@ static struct io_wq_work *io_get_next_work(struct io_wq= _acct *acct, raw_spin_lock(&acct->lock); if (unstalled) { clear_bit(IO_ACCT_STALLED_BIT, &acct->flags); - if (wq_has_sleeper(&wq->hash->wait)) - wake_up(&wq->hash->wait); + *need_wake =3D wq_has_sleeper(&wq->hash->wait); } } =20 @@ -607,6 +607,7 @@ static void io_worker_handle_work(struct io_wq_acct *ac= ct, =20 do { struct io_wq_work *work; + bool need_wake =3D false; =20 /* * If we got some work, mark us as busy. If we didn't, but @@ -615,7 +616,7 @@ static void io_worker_handle_work(struct io_wq_acct *ac= ct, * can't make progress, any work completion or insertion will * clear the stalled flag. */ - work =3D io_get_next_work(acct, wq); + work =3D io_get_next_work(acct, wq, &need_wake); if (work) { /* * Make sure cancelation can find this, even before @@ -631,6 +632,9 @@ static void io_worker_handle_work(struct io_wq_acct *ac= ct, =20 raw_spin_unlock(&acct->lock); =20 + if (need_wake) + wake_up(&wq->hash->wait); + if (!work) break; =20 base-commit: a8c591ed6b672915e0be57843f943a2a723aff40 --=20 2.43.0