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From: Maxime Chevallier <maxime.chevallier@bootlin.com>
To: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
Cc: Felix Fietkau <nbd@nbd.name>, Sean Wang <sean.wang@mediatek.com>,
	Lorenzo Bianconi <lorenzo@kernel.org>,
	Andrew Lunn <andrew+netdev@lunn.ch>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	AngeloGioacchino Del Regno
	<angelogioacchino.delregno@collabora.com>,
	Biao Huang <biao.huang@mediatek.com>,
	Yinghua Pan <ot_yinghua.pan@mediatek.com>,
	Bartosz Golaszewski <brgl@bgdev.pl>,
	kernel@collabora.com, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org
Subject: Re: [PATCH net v2 1/2] net: ethernet: mtk-star-emac: fix spinlock recursion issues on rx/tx poll
Date: Thu, 24 Apr 2025 11:00:16 +0200	[thread overview]
Message-ID: <20250424110016.009acccf@device-40.home> (raw)
In-Reply-To: <20250424-mtk_star_emac-fix-spinlock-recursion-issue-v2-1-f3fde2e529d8@collabora.com>

On Thu, 24 Apr 2025 10:38:48 +0200
Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com> wrote:

> Use spin_lock_irqsave and spin_unlock_irqrestore instead of spin_lock
> and spin_unlock in mtk_star_emac driver to avoid spinlock recursion
> occurrence that can happen when enabling the DMA interrupts again in
> rx/tx poll.
> 
> ```
> BUG: spinlock recursion on CPU#0, swapper/0/0
>  lock: 0xffff00000db9cf20, .magic: dead4ead, .owner: swapper/0/0,
>     .owner_cpu: 0
> CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted
>     6.15.0-rc2-next-20250417-00001-gf6a27738686c-dirty #28 PREEMPT
> Hardware name: MediaTek MT8365 Open Platform EVK (DT)
> Call trace:
>  show_stack+0x18/0x24 (C)
>  dump_stack_lvl+0x60/0x80
>  dump_stack+0x18/0x24
>  spin_dump+0x78/0x88
>  do_raw_spin_lock+0x11c/0x120
>  _raw_spin_lock+0x20/0x2c
>  mtk_star_handle_irq+0xc0/0x22c [mtk_star_emac]
>  __handle_irq_event_percpu+0x48/0x140
>  handle_irq_event+0x4c/0xb0
>  handle_fasteoi_irq+0xa0/0x1bc
>  handle_irq_desc+0x34/0x58
>  generic_handle_domain_irq+0x1c/0x28
>  gic_handle_irq+0x4c/0x120
>  do_interrupt_handler+0x50/0x84
>  el1_interrupt+0x34/0x68
>  el1h_64_irq_handler+0x18/0x24
>  el1h_64_irq+0x6c/0x70
>  regmap_mmio_read32le+0xc/0x20 (P)
>  _regmap_bus_reg_read+0x6c/0xac
>  _regmap_read+0x60/0xdc
>  regmap_read+0x4c/0x80
>  mtk_star_rx_poll+0x2f4/0x39c [mtk_star_emac]
>  __napi_poll+0x38/0x188
>  net_rx_action+0x164/0x2c0
>  handle_softirqs+0x100/0x244
>  __do_softirq+0x14/0x20
>  ____do_softirq+0x10/0x20
>  call_on_irq_stack+0x24/0x64
>  do_softirq_own_stack+0x1c/0x40
>  __irq_exit_rcu+0xd4/0x10c
>  irq_exit_rcu+0x10/0x1c
>  el1_interrupt+0x38/0x68
>  el1h_64_irq_handler+0x18/0x24
>  el1h_64_irq+0x6c/0x70
>  cpuidle_enter_state+0xac/0x320 (P)
>  cpuidle_enter+0x38/0x50
>  do_idle+0x1e4/0x260
>  cpu_startup_entry+0x34/0x3c
>  rest_init+0xdc/0xe0
>  console_on_rootfs+0x0/0x6c
>  __primary_switched+0x88/0x90
> ```
> 
> Fixes: 0a8bd81fd6aa ("net: ethernet: mtk-star-emac: separate tx/rx handling with two NAPIs")
> Signed-off-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
> ---

This looks correct to me,

Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>

Maxime

  reply	other threads:[~2025-04-24  9:00 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-24  8:38 [PATCH net v2 0/2] net: ethernet: mtk-star-emac: fix several issues on rx/tx poll Louis-Alexis Eyraud
2025-04-24  8:38 ` [PATCH net v2 1/2] net: ethernet: mtk-star-emac: fix spinlock recursion " Louis-Alexis Eyraud
2025-04-24  9:00   ` Maxime Chevallier [this message]
2025-04-24  9:30   ` Bartosz Golaszewski
2025-04-24  8:38 ` [PATCH net v2 2/2] net: ethernet: mtk-star-emac: rearm interrupts in rx_poll only when advised Louis-Alexis Eyraud
2025-04-24  9:16   ` Maxime Chevallier
2025-04-26  2:13     ` Jakub Kicinski
2025-04-24  9:31   ` Bartosz Golaszewski
2025-04-26  2:20 ` [PATCH net v2 0/2] net: ethernet: mtk-star-emac: fix several issues on rx/tx poll patchwork-bot+netdevbpf

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