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Matt Redfearn 4a665d628f irqchip/mips-gic: Avoid spuriously handling masked interrupts
commit 285cb4f623 upstream.

Commit 7778c4b27c ("irqchip: mips-gic: Use pcpu_masks to avoid reading
GIC_SH_MASK*") removed the read of the hardware mask register when
handling shared interrupts, instead using the driver's shadow pcpu_masks
entry as the effective mask. Unfortunately this did not take account of
the write to pcpu_masks during gic_shared_irq_domain_map, which
effectively unmasks the interrupt early. If an interrupt is asserted,
gic_handle_shared_int decodes and processes the interrupt even though it
has not yet been unmasked via gic_unmask_irq, which also sets the
appropriate bit in pcpu_masks.

On the MIPS Boston board, when a console command line of
"console=ttyS0,115200n8r" is passed, the modem status IRQ is enabled in
the UART, which is immediately raised to the GIC. The interrupt has been
mapped, but no handler has yet been registered, nor is it expected to be
unmasked. However, the write to pcpu_masks in gic_shared_irq_domain_map
has effectively unmasked it, resulting in endless reports of:

[    5.058454] irq 13, desc: ffffffff80a7ad80, depth: 1, count: 0, unhandled: 0
[    5.062057] ->handle_irq():  ffffffff801b1838,
[    5.062175] handle_bad_irq+0x0/0x2c0

Where IRQ 13 is the UART interrupt.

To fix this, just remove the write to pcpu_masks in
gic_shared_irq_domain_map. The existing write in gic_unmask_irq is the
correct place for what is now the effective unmasking.

Cc: stable@vger.kernel.org
Fixes: 7778c4b27c ("irqchip: mips-gic: Use pcpu_masks to avoid reading GIC_SH_MASK*")
Signed-off-by: Matt Redfearn <matt.redfearn@mips.com>
Reviewed-by: Paul Burton <paul.burton@mips.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-28 10:19:41 +01:00
Documentation ext4: correct documentation for grpid mount option 2018-02-22 15:42:26 +01:00
arch x86/oprofile: Fix bogus GCC-8 warning in nmi_setup() 2018-02-28 10:19:41 +01:00
block blk_rq_map_user_iov: fix error override 2018-02-25 11:07:49 +01:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto PKCS#7: fix certificate blacklisting 2018-02-28 10:19:39 +01:00
drivers irqchip/mips-gic: Avoid spuriously handling masked interrupts 2018-02-28 10:19:41 +01:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs btrfs: Fix possible off-by-one in btrfs_search_path_in_tree 2018-02-25 11:08:00 +01:00
include Kbuild: always define endianess in kconfig.h 2018-02-28 10:19:41 +01:00
init kmemcheck: stop using GFP_NOTRACK and SLAB_NOTRACK 2018-02-22 15:42:23 +01:00
ipc License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kernel locking/lockdep: Fix possible NULL deref 2018-02-25 11:08:00 +01:00
lib 509: fix printing uninitialized stack memory when OID is empty 2018-02-25 11:08:01 +01:00
mm mm, swap, frontswap: fix THP swap if frontswap enabled 2018-02-28 10:19:41 +01:00
net cfg80211: fix cfg80211_beacon_dup 2018-02-28 10:19:39 +01:00
samples samples/bpf: adjust rlimit RLIMIT_MEMLOCK for xdp1 2017-12-20 10:10:31 +01:00
scripts scripts/kernel-doc: Don't fail with status != 0 if error encountered with -none 2018-02-25 11:07:58 +01:00
security selinux: skip bounded transition processing if the policy isn't loaded 2018-02-25 11:07:49 +01:00
sound ASoC: rsnd: ssi: fix race condition in rsnd_ssi_pointer_update 2018-02-25 11:08:02 +01:00
tools perf test: Fix test 21 for s390x 2018-02-25 11:07:55 +01:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt KVM: arm/arm64: Fix spinlock acquisition in vgic_set_owner 2018-02-25 11:07:56 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: rpm-pkg: keep spec file until make mrproper 2018-02-13 10:19:46 +01:00
.mailmap .mailmap: Add Maciej W. Rozycki's Imagination e-mail address 2017-11-10 12:16:15 -08:00
COPYING
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS kmemcheck: rip it out 2018-02-22 15:42:24 +01:00
Makefile Linux 4.14.22 2018-02-25 11:08:04 +01:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.