From patchwork Wed Oct 17 14:03:10 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anders Roxell X-Patchwork-Id: 149072 Delivered-To: patch@linaro.org Received: by 2002:a2e:8595:0:0:0:0:0 with SMTP id b21-v6csp696464lji; Wed, 17 Oct 2018 07:03:27 -0700 (PDT) X-Google-Smtp-Source: ACcGV63xoCYV752rLNF9YlCVoH+w4JXEKbnfd3q+obw1prG45SdPjBuhWdo4WZIaROdoIIFAw5LU X-Received: by 2002:a17:902:1c3:: with SMTP id b61-v6mr13047743plb.65.1539785007081; Wed, 17 Oct 2018 07:03:27 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1539785007; cv=none; d=google.com; s=arc-20160816; b=zVXR6sUdgmD1H7o3gYl9/t715YOhDFBTempuJ9aE53nmKUzzRIDzt0qVbSJ7E20wVD Pf64QltnwwqfAzAwFZe26isXzSDmGER7/BhCqfxyqVX2XA0Y93oB3Bp/tXFPUYuBkLEm YxWnysYIhhd2K+4neEc+VnnQQ0RztrctqjrYJ+GXkKPzOkDnEhrTObgtDKksT7krR+rS 7DUp9PSK2tRCVXASVHoIlnNHZ3eYp6q/IkndKwwM+lKrddN2noz8U9KYEzZmcfGaw5C2 fRfq/9gouT6IFNKTt0SmbpdvrOiyDhM0uIxA61p9zmRAw7SQ3pd38xkmw+D497g/rjOM EHvg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :message-id:date:subject:cc:to:from:dkim-signature; bh=2OVLIv4pvK4XbXbssL49o+sbDOxAj20Y8ait05owHZA=; b=J5GP6IpjmVk3HJzz3KQcHIUG3zlYQ+y2c+lhfZlO1ViVJdeqLTWvyTPJViWyl5Z4Sp 7ifwckh4NTBQn1gZcU0mxOe6C9y1h7YxZA6TQ/p1pfCK/vUTOPMC/6R2l2//laV+YBq/ Ak6JHeFHBkmJQc/8pKX4vL4bnWe8t/B2hgasIvNxf2Wwoyzvkl8laOcN+AeMpRdiQIRA eBvhKokSx8VWV/HMu6kZBr/BH3t41v0EUJCoszp57Q4ZeqCG4Avk1kDwkRX8ysmGi4+u ax0QAno3GOMFIq3NOGvv2+hHQgjk23JNQ39L8AfoHsQdMOcI4n91DXM0SckDvrqEsfXY bbJQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=gR94kALd; spf=pass (google.com: best guess record for domain of linux-serial-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-serial-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. 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[213.113.33.115]) by smtp.gmail.com with ESMTPSA id y3-v6sm4093739ljy.95.2018.10.17.07.03.22 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 17 Oct 2018 07:03:22 -0700 (PDT) From: Anders Roxell To: linux@armlinux.org.uk, gregkh@linuxfoundation.org, akpm@linux-foundation.org Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, tj@kernel.org, Anders Roxell , Arnd Bergmann Subject: [PATCH 1/2] serial: set suppress_bind_attrs flag only if builtin Date: Wed, 17 Oct 2018 16:03:10 +0200 Message-Id: <20181017140311.28679-1-anders.roxell@linaro.org> X-Mailer: git-send-email 2.19.1 MIME-Version: 1.0 Sender: linux-serial-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org When the test 'CONFIG_DEBUG_TEST_DRIVER_REMOVE=y' is enabled, arch_initcall(pl011_init) came before subsys_initcall(default_bdi_init). devtmpfs gets killed because we try to remove a file and decrement the wb reference count before the noop_backing_device_info gets initialized. [ 0.332075] Serial: AMBA PL011 UART driver [ 0.485276] 9000000.pl011: ttyAMA0 at MMIO 0x9000000 (irq = 39, base_baud = 0) is a PL011 rev1 [ 0.502382] console [ttyAMA0] enabled [ 0.515710] Unable to handle kernel paging request at virtual address 0000800074c12000 [ 0.516053] Mem abort info: [ 0.516222] ESR = 0x96000004 [ 0.516417] Exception class = DABT (current EL), IL = 32 bits [ 0.516641] SET = 0, FnV = 0 [ 0.516826] EA = 0, S1PTW = 0 [ 0.516984] Data abort info: [ 0.517149] ISV = 0, ISS = 0x00000004 [ 0.517339] CM = 0, WnR = 0 [ 0.517553] [0000800074c12000] user address but active_mm is swapper [ 0.517928] Internal error: Oops: 96000004 [#1] PREEMPT SMP [ 0.518305] Modules linked in: [ 0.518839] CPU: 0 PID: 13 Comm: kdevtmpfs Not tainted 4.19.0-rc5-next-20180928-00002-g2ba39ab0cd01-dirty #82 [ 0.519307] Hardware name: linux,dummy-virt (DT) [ 0.519681] pstate: 80000005 (Nzcv daif -PAN -UAO) [ 0.519959] pc : __destroy_inode+0x94/0x2a8 [ 0.520212] lr : __destroy_inode+0x78/0x2a8 [ 0.520401] sp : ffff0000098c3b20 [ 0.520590] x29: ffff0000098c3b20 x28: 00000000087a3714 [ 0.520904] x27: 0000000000002000 x26: 0000000000002000 [ 0.521179] x25: ffff000009583000 x24: 0000000000000000 [ 0.521467] x23: ffff80007bb52000 x22: ffff80007bbaa7c0 [ 0.521737] x21: ffff0000093f9338 x20: 0000000000000000 [ 0.522033] x19: ffff80007bbb05d8 x18: 0000000000000400 [ 0.522376] x17: 0000000000000000 x16: 0000000000000000 [ 0.522727] x15: 0000000000000400 x14: 0000000000000400 [ 0.523068] x13: 0000000000000001 x12: 0000000000000001 [ 0.523421] x11: 0000000000000000 x10: 0000000000000970 [ 0.523749] x9 : ffff0000098c3a60 x8 : ffff80007bbab190 [ 0.524017] x7 : ffff80007bbaa880 x6 : 0000000000000c88 [ 0.524305] x5 : ffff0000093d96c8 x4 : 61c8864680b583eb [ 0.524567] x3 : ffff0000093d6180 x2 : ffffffffffffffff [ 0.524872] x1 : 0000800074c12000 x0 : 0000800074c12000 [ 0.525207] Process kdevtmpfs (pid: 13, stack limit = 0x(____ptrval____)) [ 0.525529] Call trace: [ 0.525806] __destroy_inode+0x94/0x2a8 [ 0.526108] destroy_inode+0x34/0x88 [ 0.526370] evict+0x144/0x1c8 [ 0.526636] iput+0x184/0x230 [ 0.526871] dentry_unlink_inode+0x118/0x130 [ 0.527152] d_delete+0xd8/0xe0 [ 0.527420] vfs_unlink+0x240/0x270 [ 0.527665] handle_remove+0x1d8/0x330 [ 0.527875] devtmpfsd+0x138/0x1c8 [ 0.528085] kthread+0x14c/0x158 [ 0.528291] ret_from_fork+0x10/0x18 [ 0.528720] Code: 92800002 aa1403e0 d538d081 8b010000 (c85f7c04) [ 0.529367] ---[ end trace 5a3dee47727f877c ]--- Rework to set suppress_bind_attrs flag to avoid removing the device when CONFIG_DEBUG_TEST_DRIVER_REMOVE=y. This applies for pic32_uart and xilinx_uartps as well. Cc: Arnd Bergmann Co-developed-by: Arnd Bergmann Signed-off-by: Anders Roxell --- drivers/tty/serial/amba-pl011.c | 2 ++ drivers/tty/serial/pic32_uart.c | 1 + drivers/tty/serial/xilinx_uartps.c | 1 + 3 files changed, 4 insertions(+) -- 2.19.1 diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index ebd33c0232e6..89ade213a1a9 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -2780,6 +2780,7 @@ static struct platform_driver arm_sbsa_uart_platform_driver = { .name = "sbsa-uart", .of_match_table = of_match_ptr(sbsa_uart_of_match), .acpi_match_table = ACPI_PTR(sbsa_uart_acpi_match), + .suppress_bind_attrs = IS_BUILTIN(CONFIG_SERIAL_AMBA_PL011), }, }; @@ -2808,6 +2809,7 @@ static struct amba_driver pl011_driver = { .drv = { .name = "uart-pl011", .pm = &pl011_dev_pm_ops, + .suppress_bind_attrs = IS_BUILTIN(CONFIG_SERIAL_AMBA_PL011), }, .id_table = pl011_ids, .probe = pl011_probe, diff --git a/drivers/tty/serial/pic32_uart.c b/drivers/tty/serial/pic32_uart.c index fd80d999308d..0bdf1687983f 100644 --- a/drivers/tty/serial/pic32_uart.c +++ b/drivers/tty/serial/pic32_uart.c @@ -919,6 +919,7 @@ static struct platform_driver pic32_uart_platform_driver = { .driver = { .name = PIC32_DEV_NAME, .of_match_table = of_match_ptr(pic32_serial_dt_ids), + .suppress_bind_attrs = IS_BUILTIN(CONFIG_SERIAL_PIC32), }, }; diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index 0e3dae461f71..806a953ac8d4 100644 --- a/drivers/tty/serial/xilinx_uartps.c +++ b/drivers/tty/serial/xilinx_uartps.c @@ -1717,6 +1717,7 @@ static struct platform_driver cdns_uart_platform_driver = { .name = CDNS_UART_NAME, .of_match_table = cdns_uart_of_match, .pm = &cdns_uart_dev_pm_ops, + .suppress_bind_attrs = IS_BUILTIN(CONFIG_SERIAL_XILINX_PS_UART), }, }; From patchwork Wed Oct 17 14:03:11 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anders Roxell X-Patchwork-Id: 149073 Delivered-To: patch@linaro.org Received: by 2002:a2e:8595:0:0:0:0:0 with SMTP id b21-v6csp696673lji; Wed, 17 Oct 2018 07:03:37 -0700 (PDT) X-Google-Smtp-Source: ACcGV612s3THfpWXI73WaLiN30ZJxNJQNYIX6Ueq/g219RxNxynoiybBEp7TolS181EJP+D4bkPO X-Received: by 2002:a63:4107:: with SMTP id o7-v6mr24873363pga.256.1539785017147; Wed, 17 Oct 2018 07:03:37 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1539785017; cv=none; d=google.com; s=arc-20160816; b=NZ/jL6e1PXP9K4kz1RpjV5iemUpZKuluaQ2hYf6qu602tmdjOg5gs+gSHp92JRlwrm OSUMTvrDFOFnv29d3G2R/PwrA05jswsYxQlgX90x6DrIaZ2EoAQBzTY9gm/V46OKPfPY oHMntrU5G5TM5yLk4a/PqwSHVBlzpWY9V64lBko05as0Zf72MHdvZIbZZqp71akYcxGK ASQtxEDgYzvpaofFw3sdIRxFulUBF5E6Qjt8XNQHRWC2TYDdaQJnKvG2qAUDfgFl1WUJ MoB0EOoeS6/cZdBHYZlJbcKUzsctOMFh9HLJVfhpmt+RxcyJUxKfT+6u2dBap29MQUcp L1OA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=FYD5OgbslaSN2IMFW2M3a1vvfCw0/W1XvkhV0Wehs50=; b=UmQGGbkRt2j/N/jeGPnBJ0bE+vR6YsDa0m+Ow69ZUtRpMDp73uYyf+lgaXO2Zuis/7 Iv62pK/w/jZTsO5BQuPRq8XkqrRIeWXn7pO8Y5d88b6TGXrqDH1znKabrqsfy/7S13gY aaVOl2ykvMGUhJlVkF4Urys3dUoGCltnlUTEXYtAIeA1D/WYptJlM7rF4Tw4UFFktH8N jyJWBtuqB/Ky4rnIw/1PN7RxfjkTkvkeKd89XRsvM/lPsT+T+Jm4chHR5/7WkGdb7oPj Xi+Qc8S2Zi22x8aat4EKFimWJkx4gmr7tRo90sbMPq5YWh/5lBwhAAvf3GI/GSU98NE0 b45w== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=O4IetBcJ; spf=pass (google.com: best guess record for domain of linux-serial-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-serial-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. 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[213.113.33.115]) by smtp.gmail.com with ESMTPSA id o101-v6sm3931820lfg.53.2018.10.17.07.03.32 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 17 Oct 2018 07:03:32 -0700 (PDT) From: Anders Roxell To: linux@armlinux.org.uk, gregkh@linuxfoundation.org, akpm@linux-foundation.org Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, tj@kernel.org, Anders Roxell , Arnd Bergmann Subject: [PATCH 2/2] writeback: don't decrement wb->refcnt if !wb->bdi Date: Wed, 17 Oct 2018 16:03:11 +0200 Message-Id: <20181017140311.28679-2-anders.roxell@linaro.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181017140311.28679-1-anders.roxell@linaro.org> References: <20181017140311.28679-1-anders.roxell@linaro.org> MIME-Version: 1.0 Sender: linux-serial-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org When enabling CONFIG_DEBUG_TEST_DRIVER_REMOVE devtmpfs gets killed because we try to remove a file and decrement the wb reference count before the noop_backing_device_info gets initialized. Since arch_initcall(pl011_init) came before subsys_initcall(default_bdi_init), devtmpfs' handle_remove() crashes because the reference count is a NULL pointer only because bdi->wb hasn't been initialized yet. [ 0.332075] Serial: AMBA PL011 UART driver [ 0.485276] 9000000.pl011: ttyAMA0 at MMIO 0x9000000 (irq = 39, base_baud = 0) is a PL011 rev1 [ 0.502382] console [ttyAMA0] enabled [ 0.515710] Unable to handle kernel paging request at virtual address 0000800074c12000 [ 0.516053] Mem abort info: [ 0.516222] ESR = 0x96000004 [ 0.516417] Exception class = DABT (current EL), IL = 32 bits [ 0.516641] SET = 0, FnV = 0 [ 0.516826] EA = 0, S1PTW = 0 [ 0.516984] Data abort info: [ 0.517149] ISV = 0, ISS = 0x00000004 [ 0.517339] CM = 0, WnR = 0 [ 0.517553] [0000800074c12000] user address but active_mm is swapper [ 0.517928] Internal error: Oops: 96000004 [#1] PREEMPT SMP [ 0.518305] Modules linked in: [ 0.518839] CPU: 0 PID: 13 Comm: kdevtmpfs Not tainted 4.19.0-rc5-next-20180928-00002-g2ba39ab0cd01-dirty #82 [ 0.519307] Hardware name: linux,dummy-virt (DT) [ 0.519681] pstate: 80000005 (Nzcv daif -PAN -UAO) [ 0.519959] pc : __destroy_inode+0x94/0x2a8 [ 0.520212] lr : __destroy_inode+0x78/0x2a8 [ 0.520401] sp : ffff0000098c3b20 [ 0.520590] x29: ffff0000098c3b20 x28: 00000000087a3714 [ 0.520904] x27: 0000000000002000 x26: 0000000000002000 [ 0.521179] x25: ffff000009583000 x24: 0000000000000000 [ 0.521467] x23: ffff80007bb52000 x22: ffff80007bbaa7c0 [ 0.521737] x21: ffff0000093f9338 x20: 0000000000000000 [ 0.522033] x19: ffff80007bbb05d8 x18: 0000000000000400 [ 0.522376] x17: 0000000000000000 x16: 0000000000000000 [ 0.522727] x15: 0000000000000400 x14: 0000000000000400 [ 0.523068] x13: 0000000000000001 x12: 0000000000000001 [ 0.523421] x11: 0000000000000000 x10: 0000000000000970 [ 0.523749] x9 : ffff0000098c3a60 x8 : ffff80007bbab190 [ 0.524017] x7 : ffff80007bbaa880 x6 : 0000000000000c88 [ 0.524305] x5 : ffff0000093d96c8 x4 : 61c8864680b583eb [ 0.524567] x3 : ffff0000093d6180 x2 : ffffffffffffffff [ 0.524872] x1 : 0000800074c12000 x0 : 0000800074c12000 [ 0.525207] Process kdevtmpfs (pid: 13, stack limit = 0x(____ptrval____)) [ 0.525529] Call trace: [ 0.525806] __destroy_inode+0x94/0x2a8 [ 0.526108] destroy_inode+0x34/0x88 [ 0.526370] evict+0x144/0x1c8 [ 0.526636] iput+0x184/0x230 [ 0.526871] dentry_unlink_inode+0x118/0x130 [ 0.527152] d_delete+0xd8/0xe0 [ 0.527420] vfs_unlink+0x240/0x270 [ 0.527665] handle_remove+0x1d8/0x330 [ 0.527875] devtmpfsd+0x138/0x1c8 [ 0.528085] kthread+0x14c/0x158 [ 0.528291] ret_from_fork+0x10/0x18 [ 0.528720] Code: 92800002 aa1403e0 d538d081 8b010000 (c85f7c04) [ 0.529367] ---[ end trace 5a3dee47727f877c ]--- Rework so that wb_put have an extra check if wb->bdi before decrement wb->refcnt and also add a WARN_ON to get a warning if it happens again in other drivers. Fixes: 52ebea749aae ("writeback: make backing_dev_info host cgroup-specific bdi_writebacks") Cc: Arnd Bergmann Co-developed-by: Arnd Bergmann Signed-off-by: Anders Roxell --- include/linux/backing-dev-defs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.19.1 Signed-off-by: Arnd, please. diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h index 9a6bc0951cfa..20721550d32a 100644 --- a/include/linux/backing-dev-defs.h +++ b/include/linux/backing-dev-defs.h @@ -258,7 +258,7 @@ static inline void wb_get(struct bdi_writeback *wb) */ static inline void wb_put(struct bdi_writeback *wb) { - if (wb != &wb->bdi->wb) + if (!WARN_ON(!wb->bdi) && wb != &wb->bdi->wb) percpu_ref_put(&wb->refcnt); }