From: Geert Uytterhoeven <geert+renesas@glider.be>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Gilad Ben-Yossef <gilad@benyossef.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
"David S . Miller" <davem@davemloft.net>,
"Rafael J . Wysocki" <rafael@kernel.org>
Cc: Rob Clark <robdclark@gmail.com>, Sean Paul <sean@poorly.run>,
Felipe Balbi <balbi@kernel.org>,
Alan Stern <stern@rowland.harvard.edu>,
Thierry Reding <thierry.reding@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Mathias Nyman <mathias.nyman@intel.com>,
Matthias Brugger <matthias.bgg@gmail.com>,
Chunfeng Yun <chunfeng.yun@mediatek.com>, Bin Liu <b-liu@ti.com>,
linux-crypto@vger.kernel.org, linux-pm@vger.kernel.org,
linux-renesas-soc@vger.kernel.org, linux-usb@vger.kernel.org,
linux-kernel@vger.kernel.org,
Geert Uytterhoeven <geert+renesas@glider.be>
Subject: [PATCH 0/2] Fix debugfs register access while suspended
Date: Fri, 24 Jan 2020 14:29:55 +0100 [thread overview]
Message-ID: <20200124132957.15769-1-geert+renesas@glider.be> (raw)
Hi all,
While comparing register values read from debugfs files under
/sys/kernel/debug/ccree/, I noticed some oddities.
Apparently there is no guarantee these registers are read from the
device while it is resumed. This may lead to bogus values, or crashes
and lock-ups.
This patch series:
1. Allows debugfs_create_regset32() to be used for devices whose
registers must be accessed when resumed,
2. Fixes the CCREE driver to make use of this.
I have identified several other drivers that may be affected (i.e.
using debugfs_create_regset32() and pm_runtime_*()):
- drivers/gpu/drm/msm/disp/dpu1
- drivers/usb/dwc3
- drivers/usb/host/ehci-omap.c
- drivers/usb/host/ehci-tegra.c
- drivers/usb/host/ohci-platform.c
- drivers/usb/host/xhci.c
- drivers/usb/host/xhci-dbgcap.c
- drivers/usb/host/xhci-histb.c
- drivers/usb/host/xhci-hub.c
- drivers/usb/host/xhci-mtk.c
- drivers/usb/host/xhci-pci.c
- drivers/usb/host/xhci-plat.c
- drivers/usb/host/xhci-tegra.c
- drivers/usb/mtu3
- drivers/usb/musb
Some of these call pm_runtime_forbid(), but given the comment "users
should enable runtime pm using power/control in sysfs", this can be
overridden from userspace, so these are unsafe, too?
Thanks for your comments!
Geert Uytterhoeven (2):
debugfs: regset32: Add Runtime PM support
crypto: ccree - fix debugfs register access while suspended
drivers/crypto/ccree/cc_debugfs.c | 2 ++
fs/debugfs/file.c | 8 ++++++++
include/linux/debugfs.h | 1 +
3 files changed, 11 insertions(+)
--
2.17.1
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
next reply other threads:[~2020-01-24 13:30 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-24 13:29 Geert Uytterhoeven [this message]
2020-01-24 13:29 ` [PATCH 1/2] debugfs: regset32: Add Runtime PM support Geert Uytterhoeven
2020-01-31 10:13 ` Rafael J. Wysocki
2020-02-10 19:01 ` Greg Kroah-Hartman
2020-01-24 13:29 ` [PATCH 2/2] crypto: ccree - fix debugfs register access while suspended Geert Uytterhoeven
2020-01-26 13:32 ` Gilad Ben-Yossef
2020-01-31 10:11 ` Rafael J. Wysocki
2020-01-24 16:24 ` [PATCH 0/2] Fix " Niklas Söderlund
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