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Filename Latest commit message Latest commit date
Michael Kelley ca61dc0c2f Drivers: hv: vmbus: Don't release fb_mmio resource in vmbus_free_mmio()
[ Upstream commit 73fe9073c0cc28056cb9de0c8a516dac070f1d1f ]

The VMBus driver manages the MMIO space it owns via the hyperv_mmio
resource tree. Because the synthetic video framebuffer portion of the
MMIO space is initially setup by the Hyper-V host for each guest, the
VMBus driver does an early reserve of that portion of MMIO space in the
hyperv_mmio resource tree. It saves a pointer to that resource in
fb_mmio. When a VMBus driver requests MMIO space and passes "true"
for the "fb_overlap_ok" argument, the reserved framebuffer space is
used if possible. In that case it's not necessary to do another request
against the "shadow" hyperv_mmio resource tree because that resource
was already requested in the early reserve steps.

However, the vmbus_free_mmio() function currently does no special
handling for the fb_mmio resource. When a framebuffer device is
removed, or the driver is unbound, the current code for
vmbus_free_mmio() releases the reserved resource, leaving fb_mmio
pointing to memory that has been freed. If the same or another
driver is subsequently bound to the device, vmbus_allocate_mmio()
checks against fb_mmio, and potentially gets garbage. Furthermore
a second unbind operation produces this "nonexistent resource" error
because of the unbalanced behavior between vmbus_allocate_mmio() and
vmbus_free_mmio():

[   55.499643] resource: Trying to free nonexistent
			resource <0x00000000f0000000-0x00000000f07fffff>

Fix this by adding logic to vmbus_free_mmio() to recognize when
MMIO space in the fb_mmio reserved area would be released, and don't
release it. This filtering ensures the fb_mmio resource always exists,
and makes vmbus_free_mmio() more parallel with vmbus_allocate_mmio().

Fixes: be000f93e5 ("drivers:hv: Track allocations of children of hv_vmbus in private resource tree")
Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Link: https://lore.kernel.org/r/20250310035208.275764-1-mhklinux@outlook.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <20250310035208.275764-1-mhklinux@outlook.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10 14:29:35 +02:00
arch clockevents/drivers/i8253: Fix stop sequence for timer 0 2025-04-10 14:29:34 +02:00
block partitions: mac: fix handling of bogus partition table 2025-03-13 12:43:16 +01:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:11:22 +02:00
crypto crypto: testmgr - some more fixes to RSA test vectors 2025-03-13 12:43:21 +01:00
Documentation sched/isolation: Prevent boot crash when the boot CPU is nohz_full 2025-04-10 14:29:35 +02:00
drivers Drivers: hv: vmbus: Don't release fb_mmio resource in vmbus_free_mmio() 2025-04-10 14:29:35 +02:00
fs Squashfs: check the inode number is not the invalid value of zero 2025-03-13 12:43:32 +01:00
include netpoll: netpoll_send_skb() returns transmit status 2025-04-10 14:29:35 +02:00
init initramfs: avoid filename buffer overrun 2024-12-14 19:44:21 +01:00
ipc ipc: replace costly bailout check in sysvipc_find_ipc() 2024-09-04 13:15:02 +02:00
kernel acct: perform last write from workqueue 2025-03-13 12:43:26 +01:00
lib lib: string_helpers: silence snprintf() output truncation warning 2024-12-14 19:44:39 +01:00
LICENSES
mm mm/page_alloc: fix uninitialized variable 2025-03-13 12:43:28 +01:00
net netpoll: hold rcu read lock in __netpoll_send_skb() 2025-04-10 14:29:35 +02:00
samples samples/bpf: Fix a resource leak 2024-12-14 19:44:50 +01:00
scripts kbuild: Move -Wenum-enum-conversion to W=2 2025-03-13 12:43:09 +01:00
security ima: Fix use-after-free on a dentry's dname.name 2025-03-13 12:43:19 +01:00
sound ALSA: hda/realtek: update ALC222 depop optimize 2025-03-13 12:43:27 +01:00
tools perf bench: Fix undefined behavior in cmpworker() 2025-03-13 12:43:08 +01:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: arm64: Ignore PMCNTENSET_EL0 while checking for overflow status 2024-12-19 18:05:04 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes
.gitignore Remove *.orig pattern from .gitignore 2024-11-08 16:20:33 +01:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS iio: stx104: Move to addac subdirectory 2023-08-30 16:27:12 +02:00
Makefile Linux 5.4.291 2025-03-13 12:43:33 +01:00
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.