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Filename Latest commit message Latest commit date
Ashok Raj 1adf8c19f9 x86/hotplug: Silence APIC only after all interrupts are migrated
commit 52d6b926aabc47643cd910c85edb262b7f44c168 upstream.

There is a race when taking a CPU offline. Current code looks like this:

native_cpu_disable()
{
	...
	apic_soft_disable();
	/*
	 * Any existing set bits for pending interrupt to
	 * this CPU are preserved and will be sent via IPI
	 * to another CPU by fixup_irqs().
	 */
	cpu_disable_common();
	{
		....
		/*
		 * Race window happens here. Once local APIC has been
		 * disabled any new interrupts from the device to
		 * the old CPU are lost
		 */
		fixup_irqs(); // Too late to capture anything in IRR.
		...
	}
}

The fix is to disable the APIC *after* cpu_disable_common().

Testing was done with a USB NIC that provided a source of frequent
interrupts. A script migrated interrupts to a specific CPU and
then took that CPU offline.

Fixes: 60dcaad573 ("x86/hotplug: Silence APIC and NMI when CPU is dead")
Reported-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Tested-by: Evan Green <evgreen@chromium.org>
Reviewed-by: Evan Green <evgreen@chromium.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/lkml/875zdarr4h.fsf@nanos.tec.linutronix.de/
Link: https://lore.kernel.org/r/1598501530-45821-1-git-send-email-ashok.raj@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-03 11:27:06 +02:00
arch x86/hotplug: Silence APIC only after all interrupts are migrated 2020-09-03 11:27:06 +02:00
block blk-mq: order adding requests to hctx->dispatch and checking SCHED_RESTART 2020-09-03 11:27:01 +02:00
certs
crypto crypto: af_alg - Work around empty control messages without MSG_MORE 2020-09-03 11:27:05 +02:00
Documentation kbuild: support LLVM=1 to switch the default tools to Clang/LLVM 2020-08-26 10:40:47 +02:00
drivers irqchip/stm32-exti: Avoid losing interrupts due to clearing pending bits by mistake 2020-09-03 11:27:06 +02:00
fs writeback: Fix sync livelock due to b_dirty_time processing 2020-09-03 11:27:04 +02:00
include writeback: Fix sync livelock due to b_dirty_time processing 2020-09-03 11:27:04 +02:00
init x86: Fix early boot crash on gcc-10, third try 2020-05-20 08:20:34 +02:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel genirq/matrix: Deal with the sillyness of for_each_cpu() on UP 2020-09-03 11:27:06 +02:00
lib test_kmod: avoid potential double free in trigger_config_run_type() 2020-08-21 13:05:37 +02:00
LICENSES
mm mm/vunmap: add cond_resched() in vunmap_pmd_range 2020-09-03 11:26:52 +02:00
net can: j1939: transport: j1939_xtp_rx_dat_one(): compare own packets to detect corruptions 2020-09-03 11:26:58 +02:00
samples bpf: Fix fds_example SIGSEGV error 2020-08-19 08:16:03 +02:00
scripts kconfig: qconf: fix signal connection to invalid slots 2020-08-26 10:41:04 +02:00
security Smack: prevent underflow in smk_set_cipso() 2020-08-19 08:16:16 +02:00
sound ASoC: wm8994: Avoid attempts to read unreadable registers 2020-09-03 11:26:59 +02:00
tools selftests: disable rp_filter for icmp_redirect.sh 2020-09-03 11:26:59 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: arm64: Only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is not set 2020-08-26 10:41:08 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.61 2020-08-26 10:41:08 +02:00
README

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

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.