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bh=Gxqq8NCF6HVwevmO1JjZvMIZt+L9jEoM+QxI55ZZgMw=; b=JDOUVPCqGWd7p7mD3mOCzdOGjLBWKXOKUQzXk/z+QEBum18Tn7o/oBSAJqo4uviWJg 8y5/dqGu/ptRiwmGVC8qYkQSFzbQq5J38B2BvDLxbjJnB9ySaFkDmbDPIy6j4/QfQGJr wXzhnN5j+L6xhYykVmy6zWR71bWj0oTgMto8KmQcxsmWAXEUP9TPg6eeceM5GENP9lUX iAjxeT8IZpwLeaRaJhghlMp49FVAPR4hArc2jkzbH2cRd7pouqdhPj3S/w3O2FK5OFuq XdaWHU2prtS+Fkm/34h1tFXtJ6t7mLkzxwT+Y/octKEvZ6V4ACOcZGKxNNCqLhI0qlNW M1+Q== X-Gm-Message-State: AOAM5308AF13nFN+0NMMIumxbPbwlfAPFTmTNOtDo1RhwtzxiLyEbDVu mwlVQsCgp8ymJuCv/j2SHZdWlGHATWiK4+jyars= X-Google-Smtp-Source: ABdhPJzW+zDa07jaIg+VLfamaq0OKviXSCjIADr2Zt4zLPT/+HVYjP41UbGUQjkpemrHHoVXl54erQqEZUqLsEl4ayw= X-Received: by 2002:aca:4fd3:: with SMTP id d202mr21117225oib.142.1593686970753; Thu, 02 Jul 2020 03:49:30 -0700 (PDT) MIME-Version: 1.0 References: <1593618100-2151-1-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.com> In-Reply-To: From: "Lad, Prabhakar" Date: Thu, 2 Jul 2020 11:49:04 +0100 Message-ID: Subject: Re: [PATCH] serial: sh-sci: Initialize spinlock for uart console To: Geert Uytterhoeven Cc: Lad Prabhakar , Greg Kroah-Hartman , Jiri Slaby , Linux-Renesas , "open list:SERIAL DRIVERS" , Linux Kernel Mailing List , Biju Das Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Geert, On Thu, Jul 2, 2020 at 10:23 AM Geert Uytterhoeven wrote: > > Hi Prabhakar, > > On Wed, Jul 1, 2020 at 7:28 PM Lad, Prabhakar > wrote: > > On Wed, Jul 1, 2020 at 6:17 PM Geert Uytterhoeven wrote: > > > On Wed, Jul 1, 2020 at 5:42 PM Lad Prabhakar > > > wrote: > > > > serial core expects the spinlock to be initialized by the controller > > > > driver for serial console, this patch makes sure the spinlock is > > > > initialized, fixing the below issue: > > > > > > > > [ 0.865928] BUG: spinlock bad magic on CPU#0, swapper/0/1 > > > > [ 0.865945] lock: sci_ports+0x0/0x4c80, .magic: 00000000, .owner: /-1, .owner_cpu: 0 > > > > [ 0.865955] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.8.0-rc1+ #112 > > > > [ 0.865961] Hardware name: HopeRun HiHope RZ/G2H with sub board (DT) > > > > [ 0.865968] Call trace: > > > > [ 0.865979] dump_backtrace+0x0/0x1d8 > > > > [ 0.865985] show_stack+0x14/0x20 > > > > [ 0.865996] dump_stack+0xe8/0x130 > > > > [ 0.866006] spin_dump+0x6c/0x88 > > > > [ 0.866012] do_raw_spin_lock+0xb0/0xf8 > > > > [ 0.866023] _raw_spin_lock_irqsave+0x80/0xa0 > > > > [ 0.866032] uart_add_one_port+0x3a4/0x4e0 > > > > [ 0.866039] sci_probe+0x504/0x7c8 > > > > [ 0.866048] platform_drv_probe+0x50/0xa0 > > > > [ 0.866059] really_probe+0xdc/0x330 > > > > [ 0.866066] driver_probe_device+0x58/0xb8 > > > > [ 0.866072] device_driver_attach+0x6c/0x90 > > > > [ 0.866078] __driver_attach+0x88/0xd0 > > > > [ 0.866085] bus_for_each_dev+0x74/0xc8 > > > > [ 0.866091] driver_attach+0x20/0x28 > > > > [ 0.866098] bus_add_driver+0x14c/0x1f8 > > > > [ 0.866104] driver_register+0x60/0x110 > > > > [ 0.866109] __platform_driver_register+0x40/0x48 > > > > [ 0.866119] sci_init+0x2c/0x34 > > > > [ 0.866127] do_one_initcall+0x88/0x428 > > > > [ 0.866137] kernel_init_freeable+0x2c0/0x328 > > > > [ 0.866143] kernel_init+0x10/0x108 > > > > [ 0.866150] ret_from_fork+0x10/0x18 > > > > > > Interesting... > > > > > > How can I reproduce that? I do have CONFIG_DEBUG_SPINLOCK=y. > > > I'm wondering why haven't we seen this before... > > > > > I have attached .config for your reference. > > Thank you! > > I gave it a try with v5.8-rc1 on Salvator-XS with R-Car H3 ES2.0. > However, I couldn't reproduce the issue. > Does it happen on that specific board only? Is this serdev-related? > Note that I had to disable CONFIG_EXTRA_FIRMWARE, as I don't have the > firmware blobs it referenced. Do I need them to trigger the issue? > As the .config has a few non-upstream options, do you have any patches > applied that might impact the issue? > Can't think of any patches that might cause an issue, most of it are just the DT's and config additions. Nor do firmware blobs should affect it. I'll try and reproduce it on M3N and get back to you. Cheers, --Prabhakar > Thanks again! > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds