Re: [PATCH v3 1/1] scsi: ufs: core: Fix &hwq->cq_lock deadlock issue

AngeloGioacchino Del Regno
2023-04-24T08:07:23Z

Il 24/04/23 10:03, Alice Chao ha scritto:
> [name:lockdep&]WARNING: inconsistent lock state
> [name:lockdep&]--------------------------------
> [name:lockdep&]inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
> [name:lockdep&]kworker/u16:4/260 [HC0[0]:SC0[0]:HE1:SE1] takes:
> ffffff8028444600 (&hwq->cq_lock){?.-.}-{2:2}, at:
> ufshcd_mcq_poll_cqe_lock+0x30/0xe0
> [name:lockdep&]{IN-HARDIRQ-W} state was registered at:
> lock_acquire+0x17c/0x33c
> _raw_spin_lock+0x5c/0x7c
> ufshcd_mcq_poll_cqe_lock+0x30/0xe0
> ufs_mtk_mcq_intr+0x60/0x1bc [ufs_mediatek_mod]
> __handle_irq_event_percpu+0x140/0x3ec
> handle_irq_event+0x50/0xd8
> handle_fasteoi_irq+0x148/0x2b0
> generic_handle_domain_irq+0x4c/0x6c
> gic_handle_irq+0x58/0x134
> call_on_irq_stack+0x40/0x74
> do_interrupt_handler+0x84/0xe4
> el1_interrupt+0x3c/0x78
> <snip>
>
> Possible unsafe locking scenario:
> CPU0
> ----
> lock(&hwq->cq_lock);
> <Interrupt>
> lock(&hwq->cq_lock);
> *** DEADLOCK ***
> 2 locks held by kworker/u16:4/260:
>
> [name:lockdep&]
> stack backtrace:
> CPU: 7 PID: 260 Comm: kworker/u16:4 Tainted: G S W OE
> 6.1.17-mainline-android14-2-g277223301adb #1
> Workqueue: ufs_eh_wq_0 ufshcd_err_handler
>
> Call trace:
> dump_backtrace+0x10c/0x160
> show_stack+0x20/0x30
> dump_stack_lvl+0x98/0xd8
> dump_stack+0x20/0x60
> print_usage_bug+0x584/0x76c
> mark_lock_irq+0x488/0x510
> mark_lock+0x1ec/0x25c
> __lock_acquire+0x4d8/0xffc
> lock_acquire+0x17c/0x33c
> _raw_spin_lock+0x5c/0x7c
> ufshcd_mcq_poll_cqe_lock+0x30/0xe0
> ufshcd_poll+0x68/0x1b0
> ufshcd_transfer_req_compl+0x9c/0xc8
> ufshcd_err_handler+0x3bc/0xea0
> process_one_work+0x2f4/0x7e8
> worker_thread+0x234/0x450
> kthread+0x110/0x134
> ret_from_fork+0x10/0x20
>
> ufs_mtk_mcq_intr() could refer to
> https://lore.kernel.org/all/20230328103423.10970-3-powen.kao@mediatek.com/
>
> When ufshcd_err_handler() is executed, CQ event interrupt can enter
> waiting for the same lock. It could happened in upstream code path
> ufshcd_handle_mcq_cq_events() and also in ufs_mtk_mcq_intr(). This
> warning message will be generated when &hwq->cq_lock is used in IRQ
> context with IRQ enabled. Use ufshcd_mcq_poll_cqe_lock() with
> spin_lock_irqsave instead of spin_lock to resolve the deadlock issue.
>
> Fixes: ed975065c31c ("scsi: ufs: core: mcq: Add completion support in poll")
> Reviewed-by: Can Guo <quic_cang@quicinc.com>
> Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
> Signed-off-by: Alice Chao <alice.chao@mediatek.com>

For readability purposes only - next time please put the actual description at
the beginning and the log at the end.

Anyway,

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>