diff options
| author | Shigeru Yoshida <syoshida@redhat.com> | 2022-08-03 01:22:05 +0900 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2023-05-09 17:27:42 -0700 |
| commit | 5fc8cbe4cf0fd34ded8045c385790c3bf04f6785 (patch) | |
| tree | 11eda342b58a1835754cf475733b650a41721adc /kernel/rcu | |
| parent | ac9a78681b921877518763ba0e89202254349d1b (diff) | |
| download | linux-5fc8cbe4cf0fd34ded8045c385790c3bf04f6785.tar.gz | |
rcu-tasks: Avoid pr_info() with spin lock in cblist_init_generic()
pr_info() is called with rtp->cbs_gbl_lock spin lock locked. Because
pr_info() calls printk() that might sleep, this will result in BUG
like below:
[ 0.206455] cblist_init_generic: Setting adjustable number of callback queues.
[ 0.206463]
[ 0.206464] =============================
[ 0.206464] [ BUG: Invalid wait context ]
[ 0.206465] 5.19.0-00428-g9de1f9c8ca51 #5 Not tainted
[ 0.206466] -----------------------------
[ 0.206466] swapper/0/1 is trying to lock:
[ 0.206467] ffffffffa0167a58 (&port_lock_key){....}-{3:3}, at: serial8250_console_write+0x327/0x4a0
[ 0.206473] other info that might help us debug this:
[ 0.206473] context-{5:5}
[ 0.206474] 3 locks held by swapper/0/1:
[ 0.206474] #0: ffffffff9eb597e0 (rcu_tasks.cbs_gbl_lock){....}-{2:2}, at: cblist_init_generic.constprop.0+0x14/0x1f0
[ 0.206478] #1: ffffffff9eb579c0 (console_lock){+.+.}-{0:0}, at: _printk+0x63/0x7e
[ 0.206482] #2: ffffffff9ea77780 (console_owner){....}-{0:0}, at: console_emit_next_record.constprop.0+0x111/0x330
[ 0.206485] stack backtrace:
[ 0.206486] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-00428-g9de1f9c8ca51 #5
[ 0.206488] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.fc36 04/01/2014
[ 0.206489] Call Trace:
[ 0.206490] <TASK>
[ 0.206491] dump_stack_lvl+0x6a/0x9f
[ 0.206493] __lock_acquire.cold+0x2d7/0x2fe
[ 0.206496] ? stack_trace_save+0x46/0x70
[ 0.206497] lock_acquire+0xd1/0x2f0
[ 0.206499] ? serial8250_console_write+0x327/0x4a0
[ 0.206500] ? __lock_acquire+0x5c7/0x2720
[ 0.206502] _raw_spin_lock_irqsave+0x3d/0x90
[ 0.206504] ? serial8250_console_write+0x327/0x4a0
[ 0.206506] serial8250_console_write+0x327/0x4a0
[ 0.206508] console_emit_next_record.constprop.0+0x180/0x330
[ 0.206511] console_unlock+0xf7/0x1f0
[ 0.206512] vprintk_emit+0xf7/0x330
[ 0.206514] _printk+0x63/0x7e
[ 0.206516] cblist_init_generic.constprop.0.cold+0x24/0x32
[ 0.206518] rcu_init_tasks_generic+0x5/0xd9
[ 0.206522] kernel_init_freeable+0x15b/0x2a2
[ 0.206523] ? rest_init+0x160/0x160
[ 0.206526] kernel_init+0x11/0x120
[ 0.206527] ret_from_fork+0x1f/0x30
[ 0.206530] </TASK>
[ 0.207018] cblist_init_generic: Setting shift to 1 and lim to 1.
This patch moves pr_info() so that it is called without
rtp->cbs_gbl_lock locked.
Signed-off-by: Shigeru Yoshida <syoshida@redhat.com>
Tested-by: "Zhang, Qiang1" <qiang1.zhang@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tasks.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 5f4fc8184dd0b5..65df1aaf0ce9b8 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -241,7 +241,6 @@ static void cblist_init_generic(struct rcu_tasks *rtp) if (rcu_task_enqueue_lim < 0) { rcu_task_enqueue_lim = 1; rcu_task_cb_adjust = true; - pr_info("%s: Setting adjustable number of callback queues.\n", __func__); } else if (rcu_task_enqueue_lim == 0) { rcu_task_enqueue_lim = 1; } @@ -272,6 +271,10 @@ static void cblist_init_generic(struct rcu_tasks *rtp) raw_spin_unlock_rcu_node(rtpcp); // irqs remain disabled. } raw_spin_unlock_irqrestore(&rtp->cbs_gbl_lock, flags); + + if (rcu_task_cb_adjust) + pr_info("%s: Setting adjustable number of callback queues.\n", __func__); + pr_info("%s: Setting shift to %d and lim to %d.\n", __func__, data_race(rtp->percpu_enqueue_shift), data_race(rtp->percpu_enqueue_lim)); } |