From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, "Sascha Hauer" <s.hauer@pengutronix.de>,
"Shawn Guo" <shawnguo@kernel.org>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Thierry Reding" <thierry.reding@gmail.com>
Subject: [PATCH 4.4 09/23] pwm: mxs: Dont modify HW state in .probe() after the PWM chip was registered
Date: Fri, 24 Sep 2021 14:43:50 +0200 [thread overview]
Message-ID: <20210924124328.125888005@linuxfoundation.org> (raw)
In-Reply-To: <20210924124327.816210800@linuxfoundation.org>
From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
commit 020162d6f49f2963062229814a56a89c86cbeaa8 upstream.
This fixes a race condition: After pwmchip_add() is called there might
already be a consumer and then modifying the hardware behind the
consumer's back is bad. So reset before calling pwmchip_add().
Note that reseting the hardware isn't the right thing to do if the PWM
is already running as it might e.g. disable (or even enable) a backlight
that is supposed to be on (or off).
Fixes: 4dce82c1e840 ("pwm: add pwm-mxs support")
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/pwm/pwm-mxs.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
--- a/drivers/pwm/pwm-mxs.c
+++ b/drivers/pwm/pwm-mxs.c
@@ -158,6 +158,11 @@ static int mxs_pwm_probe(struct platform
return ret;
}
+ /* FIXME: Only do this if the PWM isn't already running */
+ ret = stmp_reset_block(mxs->base);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret, "failed to reset PWM\n");
+
ret = pwmchip_add(&mxs->chip);
if (ret < 0) {
dev_err(&pdev->dev, "failed to add pwm chip %d\n", ret);
@@ -166,15 +171,7 @@ static int mxs_pwm_probe(struct platform
platform_set_drvdata(pdev, mxs);
- ret = stmp_reset_block(mxs->base);
- if (ret)
- goto pwm_remove;
-
return 0;
-
-pwm_remove:
- pwmchip_remove(&mxs->chip);
- return ret;
}
static int mxs_pwm_remove(struct platform_device *pdev)
next prev parent reply other threads:[~2021-09-24 12:45 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-24 12:43 [PATCH 4.4 00/23] 4.4.285-rc1 review Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 01/23] s390/bpf: Fix optimizing out zero-extensions Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 02/23] PM / wakeirq: Fix unbalanced IRQ enable for wakeirq Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 03/23] sctp: validate chunk size in __rcv_asconf_lookup Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 04/23] sctp: add param size validation for SCTP_PARAM_SET_PRIMARY Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 05/23] thermal/drivers/exynos: Fix an error code in exynos_tmu_probe() Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 06/23] 9p/trans_virtio: Remove sysfs file on probe failure Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 07/23] prctl: allow to setup brk for et_dyn executables Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 08/23] profiling: fix shift-out-of-bounds bugs Greg Kroah-Hartman
2021-09-24 12:43 ` Greg Kroah-Hartman [this message]
2021-09-24 12:43 ` [PATCH 4.4 10/23] dmaengine: acpi-dma: check for 64-bit MMIO address Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 11/23] dmaengine: acpi: Avoid comparison GSI with Linux vIRQ Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 12/23] parisc: Move pci_dev_is_behind_card_dino to where it is used Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 13/23] dmaengine: ioat: depends on !UML Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 14/23] ceph: lockdep annotations for try_nonblocking_invalidate Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 15/23] nilfs2: fix memory leak in nilfs_sysfs_create_device_group Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 16/23] nilfs2: fix NULL pointer in nilfs_##name##_attr_release Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 17/23] nilfs2: fix memory leak in nilfs_sysfs_create_##name##_group Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 18/23] nilfs2: fix memory leak in nilfs_sysfs_delete_##name##_group Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.4 19/23] nilfs2: fix memory leak in nilfs_sysfs_create_snapshot_group Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.4 20/23] nilfs2: fix memory leak in nilfs_sysfs_delete_snapshot_group Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.4 21/23] blk-throttle: fix UAF by deleteing timer in blk_throtl_exit() Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.4 22/23] drm/nouveau/nvkm: Replace -ENOSYS with -ENODEV Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.4 23/23] sctp: validate from_addr_param return Greg Kroah-Hartman
2021-09-24 13:50 ` [PATCH 4.4 00/23] 4.4.285-rc1 review Daniel Díaz
2021-09-25 11:45 ` Greg Kroah-Hartman
2021-09-24 17:50 ` Jon Hunter
2021-09-24 21:50 ` Pavel Machek
2021-09-24 21:55 ` Shuah Khan
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