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Filename Latest commit message Latest commit date
Zhen Lei 6f4454ccbe kexec: fix a memory leak in crash_shrink_memory()
[ Upstream commit 1cba6c4309f03de570202c46f03df3f73a0d4c82 ]

Patch series "kexec: enable kexec_crash_size to support two crash kernel
regions".

When crashkernel=X fails to reserve region under 4G, it will fall back to
reserve region above 4G and a region of the default size will also be
reserved under 4G.  Unfortunately, /sys/kernel/kexec_crash_size only
supports one crash kernel region now, the user cannot sense the low memory
reserved by reading /sys/kernel/kexec_crash_size.  Also, low memory cannot
be freed by writing this file.

For example:
resource_size(crashk_res) = 512M
resource_size(crashk_low_res) = 256M

The result of 'cat /sys/kernel/kexec_crash_size' is 512M, but it should be
768M.  When we execute 'echo 0 > /sys/kernel/kexec_crash_size', the size
of crashk_res becomes 0 and resource_size(crashk_low_res) is still 256 MB,
which is incorrect.

Since crashk_res manages the memory with high address and crashk_low_res
manages the memory with low address, crashk_low_res is shrunken only when
all crashk_res is shrunken.  And because when there is only one crash
kernel region, crashk_res is always used.  Therefore, if all crashk_res is
shrunken and crashk_low_res still exists, swap them.

This patch (of 6):

If the value of parameter 'new_size' is in the semi-open and semi-closed
interval (crashk_res.end - KEXEC_CRASH_MEM_ALIGN + 1, crashk_res.end], the
calculation result of ram_res is:

	ram_res->start = crashk_res.end + 1
	ram_res->end   = crashk_res.end

The operation of insert_resource() fails, and ram_res is not added to
iomem_resource.  As a result, the memory of the control block ram_res is
leaked.

In fact, on all architectures, the start address and size of crashk_res
are already aligned by KEXEC_CRASH_MEM_ALIGN.  Therefore, we do not need
to round up crashk_res.start again.  Instead, we should round up
'new_size' in advance.

Link: https://lkml.kernel.org/r/20230527123439.772-1-thunder.leizhen@huawei.com
Link: https://lkml.kernel.org/r/20230527123439.772-2-thunder.leizhen@huawei.com
Fixes: 6480e5a092 ("kdump: add missing RAM resource in crash_shrink_memory()")
Fixes: 06a7f71124 ("kexec: premit reduction of the reserved memory size")
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Cong Wang <amwang@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-27 08:37:10 +02:00
arch ARM: 9303/1: kprobes: avoid missing-declaration warnings 2023-07-27 08:37:06 +02:00
block block/blk-iocost (gcc13): keep large values in a new enum 2023-06-14 10:59:54 +02:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:11:22 +02:00
crypto KEYS: asymmetric: Copy sig and digest in public_key_verify_signature() 2023-06-21 15:44:08 +02:00
Documentation Remove DECnet support from kernel 2023-06-21 15:44:10 +02:00
drivers wifi: rsi: Do not set MMC_PM_KEEP_POWER in shutdown 2023-07-27 08:37:09 +02:00
fs pstore/ram: Add check for kstrdup 2023-07-27 08:37:06 +02:00
include watchdog/perf: define dummy watchdog_update_hrtimer_threshold() on correct config 2023-07-27 08:37:10 +02:00
init init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash 2022-12-08 11:22:59 +01:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel kexec: fix a memory leak in crash_shrink_memory() 2023-07-27 08:37:10 +02:00
lib test_firmware: fix a memory leak with reqs buffer 2023-06-21 15:44:08 +02:00
LICENSES
mm mm: make wait_on_page_writeback() wait for multiple pending writebacks 2023-06-28 10:18:42 +02:00
net nfc: llcp: fix possible use of uninitialized variable in nfc_llcp_send_connect() 2023-07-27 08:37:07 +02:00
samples samples/bpf: Fix buffer overflow in tcp_basertt 2023-07-27 08:37:07 +02:00
scripts scripts/tags.sh: Resolve gtags empty index generation 2023-07-27 08:37:03 +02:00
security ima: Fix build warnings 2023-07-27 08:37:06 +02:00
sound ASoC: nau8824: Add quirk to active-high jack-detect 2023-06-28 10:18:41 +02:00
tools selftests/ptp: Fix timestamp printf format for PTP_SYS_OFFSET 2023-06-21 15:44:12 +02:00
usr
virt KVM: Destroy target device if coalesced MMIO unregistration fails 2023-03-11 16:44:01 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Remove DECnet support from kernel 2023-06-21 15:44:10 +02:00
Makefile Linux 5.4.250 2023-07-24 19:10:53 +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.