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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Rob Clark <robdclark@chromium.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 15/35] drm/msm/rd: Fix FIFO-full deadlock
Date: Fri, 16 Sep 2022 12:08:38 +0200	[thread overview]
Message-ID: <20220916100447.578855395@linuxfoundation.org> (raw)
In-Reply-To: <20220916100446.916515275@linuxfoundation.org>

From: Rob Clark <robdclark@chromium.org>

[ Upstream commit 174974d8463b77c2b4065e98513adb204e64de7d ]

If the previous thing cat'ing $debugfs/rd left the FIFO full, then
subsequent open could deadlock in rd_write() (because open is blocked,
not giving a chance for read() to consume any data in the FIFO).  Also
it is generally a good idea to clear out old data from the FIFO.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Patchwork: https://patchwork.freedesktop.org/patch/496706/
Link: https://lore.kernel.org/r/20220807160901.2353471-2-robdclark@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/msm/msm_rd.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/msm/msm_rd.c b/drivers/gpu/drm/msm/msm_rd.c
index b55398a34fa48..e3f0dd4a36792 100644
--- a/drivers/gpu/drm/msm/msm_rd.c
+++ b/drivers/gpu/drm/msm/msm_rd.c
@@ -191,6 +191,9 @@ static int rd_open(struct inode *inode, struct file *file)
 	file->private_data = rd;
 	rd->open = true;
 
+	/* Reset fifo to clear any previously unread data: */
+	rd->fifo.head = rd->fifo.tail = 0;
+
 	/* the parsing tools need to know gpu-id to know which
 	 * register database to load.
 	 */
-- 
2.35.1




  parent reply	other threads:[~2022-09-16 10:20 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-16 10:08 [PATCH 5.15 00/35] 5.15.69-rc1 review Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 01/35] NFS: Fix WARN_ON due to unionization of nfs_inode.nrequests Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 02/35] ACPI: resource: skip IRQ override on AMD Zen platforms Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 03/35] ARM: dts: imx: align SPI NOR node name with dtschema Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 04/35] ARM: dts: imx6qdl-kontron-samx6i: fix spi-flash compatible Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 05/35] ARM: dts: at91: fix low limit for CPU regulator Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 06/35] ARM: dts: at91: sama7g5ek: specify proper regulator output ranges Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 07/35] lockdep: Fix -Wunused-parameter for _THIS_IP_ Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 08/35] x86/mm: Force-inline __phys_addr_nodebug() Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 09/35] task_stack, x86/cea: Force-inline stack helpers Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 10/35] tracing: hold caller_addr to hardirq_{enable,disable}_ip Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 11/35] tracefs: Only clobber mode/uid/gid on remount if asked Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 12/35] iommu/vt-d: Fix kdump kernels boot failure with scalable mode Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 13/35] Input: goodix - add support for GT1158 Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 14/35] platform/surface: aggregator_registry: Add support for Surface Laptop Go 2 Greg Kroah-Hartman
2022-09-16 10:08 ` Greg Kroah-Hartman [this message]
2022-09-16 10:08 ` [PATCH 5.15 16/35] hwmon: (pmbus) Use dev_err_probe() to filter -EPROBE_DEFER error messages Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 17/35] dt-bindings: iio: gyroscope: bosch,bmg160: correct number of pins Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 18/35] HID: ishtp-hid-clientHID: ishtp-hid-client: Fix comment typo Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 19/35] hid: intel-ish-hid: ishtp: Fix ishtp client sending disordered message Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 20/35] tg3: Disable tg3 device on system reboot to avoid triggering AER Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 21/35] gpio: mockup: remove gpio debugfs when remove device Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 22/35] ieee802154: cc2520: add rc code in cc2520_tx() Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 23/35] Input: iforce - add support for Boeder Force Feedback Wheel Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 24/35] nvmet-tcp: fix unhandled tcp states in nvmet_tcp_state_change() Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 25/35] drm/amd/amdgpu: skip ucode loading if ucode_size == 0 Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 26/35] net: dsa: hellcreek: Print warning only once Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 27/35] perf/arm_pmu_platform: fix tests for platform_get_irq() failure Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 28/35] platform/x86: acer-wmi: Acer Aspire One AOD270/Packard Bell Dot keymap fixes Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 29/35] usb: storage: Add ASUS <0x0b05:0x1932> to IGNORE_UAS Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 30/35] mm: Fix TLB flush for not-first PFNMAP mappings in unmap_region() Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 31/35] soc: fsl: select FSL_GUTS driver for DPIO Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 32/35] usb: gadget: f_uac2: clean up some inconsistent indenting Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 33/35] usb: gadget: f_uac2: fix superspeed transfer Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 34/35] RDMA/irdma: Use s/g array in post send only when its valid Greg Kroah-Hartman
2022-09-16 10:08 ` [PATCH 5.15 35/35] Input: goodix - add compatible string for GT1158 Greg Kroah-Hartman
2022-09-16 21:48 ` [PATCH 5.15 00/35] 5.15.69-rc1 review Guenter Roeck
2022-09-17  4:11 ` Bagas Sanjaya
2022-09-17 10:19 ` Ron Economos
2022-09-17 14:09 ` Sudip Mukherjee (Codethink)
2022-09-17 15:57 ` Naresh Kamboju
2022-09-19  0:00 ` Florian Fainelli

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