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Filename Latest commit message Latest commit date
Dongli Zhang f5f4675960 genirq/cpuhotplug, x86/vector: Prevent vector leak during CPU offline
commit a6c11c0a5235fb144a65e0cb2ffd360ddc1f6c32 upstream.

The absence of IRQD_MOVE_PCNTXT prevents immediate effectiveness of
interrupt affinity reconfiguration via procfs. Instead, the change is
deferred until the next instance of the interrupt being triggered on the
original CPU.

When the interrupt next triggers on the original CPU, the new affinity is
enforced within __irq_move_irq(). A vector is allocated from the new CPU,
but the old vector on the original CPU remains and is not immediately
reclaimed. Instead, apicd->move_in_progress is flagged, and the reclaiming
process is delayed until the next trigger of the interrupt on the new CPU.

Upon the subsequent triggering of the interrupt on the new CPU,
irq_complete_move() adds a task to the old CPU's vector_cleanup list if it
remains online. Subsequently, the timer on the old CPU iterates over its
vector_cleanup list, reclaiming old vectors.

However, a rare scenario arises if the old CPU is outgoing before the
interrupt triggers again on the new CPU.

In that case irq_force_complete_move() is not invoked on the outgoing CPU
to reclaim the old apicd->prev_vector because the interrupt isn't currently
affine to the outgoing CPU, and irq_needs_fixup() returns false. Even
though __vector_schedule_cleanup() is later called on the new CPU, it
doesn't reclaim apicd->prev_vector; instead, it simply resets both
apicd->move_in_progress and apicd->prev_vector to 0.

As a result, the vector remains unreclaimed in vector_matrix, leading to a
CPU vector leak.

To address this issue, move the invocation of irq_force_complete_move()
before the irq_needs_fixup() call to reclaim apicd->prev_vector, if the
interrupt is currently or used to be affine to the outgoing CPU.

Additionally, reclaim the vector in __vector_schedule_cleanup() as well,
following a warning message, although theoretically it should never see
apicd->move_in_progress with apicd->prev_cpu pointing to an offline CPU.

Fixes: f0383c24b4 ("genirq/cpuhotplug: Add support for cleaning up move in progress")
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240522220218.162423-1-dongli.zhang@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-16 13:28:48 +02:00
arch genirq/cpuhotplug, x86/vector: Prevent vector leak during CPU offline 2024-06-16 13:28:48 +02:00
block block: prevent division by zero in blk_rq_stat_sum() 2024-04-13 12:51:38 +02:00
certs
crypto Revert "crypto: api - Disallow identical driver names" 2024-05-02 16:18:35 +02:00
Documentation ASoC: dt-bindings: rt5645: add cbj sleeve gpio property 2024-06-16 13:28:31 +02:00
drivers ipvlan: Dont Use skb->sk in ipvlan_process_v{4,6}_outbound 2024-06-16 13:28:48 +02:00
fs f2fs: fix to release node block count in error path of f2fs_new_node_page() 2024-06-16 13:28:43 +02:00
include params: lift param_set_uint_minmax to common code 2024-06-16 13:28:45 +02:00
init init: open /initrd.image with O_LARGEFILE 2024-04-13 12:51:36 +02:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel genirq/cpuhotplug, x86/vector: Prevent vector leak during CPU offline 2024-06-16 13:28:48 +02:00
lib dyndbg: fix old BUG_ON in >control parser 2024-05-17 11:43:55 +02:00
LICENSES
mm x86/mm/pat: fix VM_PAT handling in COW mappings 2024-04-13 12:51:40 +02:00
net netfilter: tproxy: bail out if IP has been disabled on the device 2024-06-16 13:28:47 +02:00
samples media: rename VFL_TYPE_GRABBER to _VIDEO 2024-03-26 18:22:22 -04:00
scripts kconfig: fix comparison to constant symbols, 'm', 'n' 2024-06-16 13:28:47 +02:00
security smack: Handle SMACK64TRANSMUTE in smack_inode_setsecurity() 2024-04-13 12:51:22 +02:00
sound ALSA: timer: Set lower bound of start tick time 2024-06-16 13:28:48 +02:00
tools libsubcmd: Fix parse-options memory leak 2024-06-16 13:28:43 +02:00
usr
virt KVM: async_pf: Cleanup kvm_setup_async_pf() 2024-05-02 16:18:32 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS iio: stx104: Move to addac subdirectory 2023-08-30 16:27:12 +02:00
Makefile Linux 5.4.277 2024-05-25 16:17:18 +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.