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Boy.Wu 20ac71bee0 ARM: 9381/1: kasan: clear stale stack poison [ Upstream commit `c4238686f9` ] We found below OOB crash: [ 33.452494] ================================================================== [ 33.453513] BUG: KASAN: stack-out-of-bounds in refresh_cpu_vm_stats.constprop.0+0xcc/0x2ec [ 33.454660] Write of size 164 at addr c1d03d30 by task swapper/0/0 [ 33.455515] [ 33.455767] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G O 6.1.25-mainline #1 [ 33.456880] Hardware name: Generic DT based system [ 33.457555] unwind_backtrace from show_stack+0x18/0x1c [ 33.458326] show_stack from dump_stack_lvl+0x40/0x4c [ 33.459072] dump_stack_lvl from print_report+0x158/0x4a4 [ 33.459863] print_report from kasan_report+0x9c/0x148 [ 33.460616] kasan_report from kasan_check_range+0x94/0x1a0 [ 33.461424] kasan_check_range from memset+0x20/0x3c [ 33.462157] memset from refresh_cpu_vm_stats.constprop.0+0xcc/0x2ec [ 33.463064] refresh_cpu_vm_stats.constprop.0 from tick_nohz_idle_stop_tick+0x180/0x53c [ 33.464181] tick_nohz_idle_stop_tick from do_idle+0x264/0x354 [ 33.465029] do_idle from cpu_startup_entry+0x20/0x24 [ 33.465769] cpu_startup_entry from rest_init+0xf0/0xf4 [ 33.466528] rest_init from arch_post_acpi_subsys_init+0x0/0x18 [ 33.467397] [ 33.467644] The buggy address belongs to stack of task swapper/0/0 [ 33.468493] and is located at offset 112 in frame: [ 33.469172] refresh_cpu_vm_stats.constprop.0+0x0/0x2ec [ 33.469917] [ 33.470165] This frame has 2 objects: [ 33.470696] [32, 76) 'global_zone_diff' [ 33.470729] [112, 276) 'global_node_diff' [ 33.471294] [ 33.472095] The buggy address belongs to the physical page: [ 33.472862] page:3cd72da8 refcount:1 mapcount:0 mapping:00000000 index:0x0 pfn:0x41d03 [ 33.473944] flags: 0x1000(reserved\|zone=0) [ 33.474565] raw: 00001000 ed741470 ed741470 00000000 00000000 00000000 ffffffff 00000001 [ 33.475656] raw: 00000000 [ 33.476050] page dumped because: kasan: bad access detected [ 33.476816] [ 33.477061] Memory state around the buggy address: [ 33.477732] c1d03c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 33.478630] c1d03c80: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00 [ 33.479526] >c1d03d00: 00 04 f2 f2 f2 f2 00 00 00 00 00 00 f1 f1 f1 f1 [ 33.480415] ^ [ 33.481195] c1d03d80: 00 00 00 00 00 00 00 00 00 00 04 f3 f3 f3 f3 f3 [ 33.482088] c1d03e00: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 [ 33.482978] ================================================================== We find the root cause of this OOB is that arm does not clear stale stack poison in the case of cpuidle. This patch refer to arch/arm64/kernel/sleep.S to resolve this issue. From cited commit [1] that explain the problem Functions which the compiler has instrumented for KASAN place poison on the stack shadow upon entry and remove this poison prior to returning. In the case of cpuidle, CPUs exit the kernel a number of levels deep in C code. Any instrumented functions on this critical path will leave portions of the stack shadow poisoned. If CPUs lose context and return to the kernel via a cold path, we restore a prior context saved in __cpu_suspend_enter are forgotten, and we never remove the poison they placed in the stack shadow area by functions calls between this and the actual exit of the kernel. Thus, (depending on stackframe layout) subsequent calls to instrumented functions may hit this stale poison, resulting in (spurious) KASAN splats to the console. To avoid this, clear any stale poison from the idle thread for a CPU prior to bringing a CPU online. From cited commit [2] Extend to check for CONFIG_KASAN_STACK [1] commit `0d97e6d802` ("arm64: kasan: clear stale stack poison") [2] commit `d56a9ef84b` ("kasan, arm64: unpoison stack only with CONFIG_KASAN_STACK") Signed-off-by: Boy Wu <boy.wu@mediatek.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Fixes: `5615f69bc2` ("ARM: 9016/2: Initialize the mapping of KASan shadow memory") Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Signed-off-by: Sasha Levin <sashal@kernel.org>		2024-05-17 11:50:57 +02:00
Documentation	Revert "lockd: introduce safe async lock op"	2024-04-27 17:05:23 +02:00
LICENSES	LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes"	2021-07-15 06:31:24 -06:00
arch	ARM: 9381/1: kasan: clear stale stack poison	2024-05-17 11:50:57 +02:00
block	blk-iocost: avoid out of bounds shift	2024-05-17 11:50:54 +02:00
certs	certs/blacklist_hashes.c: fix const confusion in certs blacklist	2022-06-22 14:22:01 +02:00
crypto	Revert "crypto: api - Disallow identical driver names"	2024-05-02 16:24:47 +02:00
drivers	qibfs: fix dentry leak	2024-05-17 11:50:57 +02:00
fs	fs/9p: drop inodes immediately on non-.L too	2024-05-17 11:50:55 +02:00
include	xfrm: Preserve vlan tags for transport mode software GRO	2024-05-17 11:50:57 +02:00
init	init/main.c: Fix potential static_command_line memory overflow	2024-04-27 17:05:28 +02:00
io_uring	io_uring: ensure '0' is returned on file registration success	2024-04-10 16:19:37 +02:00
ipc	ipc/sem: Fix dangling sem_array access in semtimedop race	2022-12-08 11:28:45 +01:00
kernel	xdp: Move conversion to xdp_frame out of map functions	2024-05-17 11:50:47 +02:00
lib	bpf, kconfig: Fix DEBUG_INFO_BTF_MODULES Kconfig definition	2024-05-17 11:50:46 +02:00
mm	x86/mm/pat: fix VM_PAT handling in COW mappings	2024-04-13 13:01:47 +02:00
net	xfrm: Preserve vlan tags for transport mode software GRO	2024-05-17 11:50:57 +02:00
samples	samples/hw_breakpoint: fix building without module unloading	2023-09-23 11:10:01 +02:00
scripts	kbuild: Disable KCSAN for autogenerated *.mod.c intermediaries	2024-05-17 11:50:53 +02:00
security	landlock: Warn once if a Landlock action is requested while disabled	2024-04-10 16:18:39 +02:00
sound	ALSA: line6: Zero-initialize message buffers	2024-05-17 11:50:53 +02:00
tools	selftests: timers: Fix valid-adjtimex signed left-shift undefined behavior	2024-05-17 11:50:54 +02:00
usr	usr/include/Makefile: add linux/nfc.h to the compile-test coverage	2022-02-01 17:27:15 +01:00
virt	KVM: Always flush async #PF workqueue when vCPU is being destroyed	2024-04-10 16:18:34 +02:00
.clang-format	clang-format: Update with the latest for_each macro list	2021-05-12 23:32:39 +02:00
.cocciconfig	…
.get_maintainer.ignore	Opt out of scripts/get_maintainer.pl	2019-05-16 10:53:40 -07:00
.gitattributes	.gitattributes: use 'dts' diff driver for dts files	2019-12-04 19:44:11 -08:00
.gitignore	.gitignore: ignore only top-level modules.builtin	2021-05-02 00:43:35 +09:00
.mailmap	mailmap: add Andrej Shadura	2021-10-18 20:22:03 -10:00
COPYING	COPYING: state that all contributions really are covered by this file	2020-02-10 13:32:20 -08:00
CREDITS	MAINTAINERS: Move Daniel Drake to credits	2021-09-21 08:34:58 +03:00
Kbuild	kbuild: rename hostprogs-y/always to hostprogs/always-y	2020-02-04 01:53:07 +09:00
Kconfig	kbuild: ensure full rebuild when the compiler is updated	2020-05-12 13:28:33 +09:00
MAINTAINERS	trace: Relocate event helper files	2024-04-10 16:19:24 +02:00
Makefile	Linux 5.15.158	2024-05-02 16:24:50 +02:00
README	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00

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.