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Alexandre Ghiti 76950340cf
riscv: Use READ_ONCE_NOCHECK in imprecise unwinding stack mode
When CONFIG_FRAME_POINTER is unset, the stack unwinding function
walk_stackframe randomly reads the stack and then, when KASAN is enabled,
it can lead to the following backtrace:

[    0.000000] ==================================================================
[    0.000000] BUG: KASAN: stack-out-of-bounds in walk_stackframe+0xa6/0x11a
[    0.000000] Read of size 8 at addr ffffffff81807c40 by task swapper/0
[    0.000000]
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 6.2.0-12919-g24203e6db61f #43
[    0.000000] Hardware name: riscv-virtio,qemu (DT)
[    0.000000] Call Trace:
[    0.000000] [<ffffffff80007ba8>] walk_stackframe+0x0/0x11a
[    0.000000] [<ffffffff80099ecc>] init_param_lock+0x26/0x2a
[    0.000000] [<ffffffff80007c4a>] walk_stackframe+0xa2/0x11a
[    0.000000] [<ffffffff80c49c80>] dump_stack_lvl+0x22/0x36
[    0.000000] [<ffffffff80c3783e>] print_report+0x198/0x4a8
[    0.000000] [<ffffffff80099ecc>] init_param_lock+0x26/0x2a
[    0.000000] [<ffffffff80007c4a>] walk_stackframe+0xa2/0x11a
[    0.000000] [<ffffffff8015f68a>] kasan_report+0x9a/0xc8
[    0.000000] [<ffffffff80007c4a>] walk_stackframe+0xa2/0x11a
[    0.000000] [<ffffffff80007c4a>] walk_stackframe+0xa2/0x11a
[    0.000000] [<ffffffff8006e99c>] desc_make_final+0x80/0x84
[    0.000000] [<ffffffff8009a04e>] stack_trace_save+0x88/0xa6
[    0.000000] [<ffffffff80099fc2>] filter_irq_stacks+0x72/0x76
[    0.000000] [<ffffffff8006b95e>] devkmsg_read+0x32a/0x32e
[    0.000000] [<ffffffff8015ec16>] kasan_save_stack+0x28/0x52
[    0.000000] [<ffffffff8006e998>] desc_make_final+0x7c/0x84
[    0.000000] [<ffffffff8009a04a>] stack_trace_save+0x84/0xa6
[    0.000000] [<ffffffff8015ec52>] kasan_set_track+0x12/0x20
[    0.000000] [<ffffffff8015f22e>] __kasan_slab_alloc+0x58/0x5e
[    0.000000] [<ffffffff8015e7ea>] __kmem_cache_create+0x21e/0x39a
[    0.000000] [<ffffffff80e133ac>] create_boot_cache+0x70/0x9c
[    0.000000] [<ffffffff80e17ab2>] kmem_cache_init+0x6c/0x11e
[    0.000000] [<ffffffff80e00fd6>] mm_init+0xd8/0xfe
[    0.000000] [<ffffffff80e011d8>] start_kernel+0x190/0x3ca
[    0.000000]
[    0.000000] The buggy address belongs to stack of task swapper/0
[    0.000000]  and is located at offset 0 in frame:
[    0.000000]  stack_trace_save+0x0/0xa6
[    0.000000]
[    0.000000] This frame has 1 object:
[    0.000000]  [32, 56) 'c'
[    0.000000]
[    0.000000] The buggy address belongs to the physical page:
[    0.000000] page:(____ptrval____) refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x81a07
[    0.000000] flags: 0x1000(reserved|zone=0)
[    0.000000] raw: 0000000000001000 ff600003f1e3d150 ff600003f1e3d150 0000000000000000
[    0.000000] raw: 0000000000000000 0000000000000000 00000001ffffffff
[    0.000000] page dumped because: kasan: bad access detected
[    0.000000]
[    0.000000] Memory state around the buggy address:
[    0.000000]  ffffffff81807b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[    0.000000]  ffffffff81807b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[    0.000000] >ffffffff81807c00: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 f3
[    0.000000]                                            ^
[    0.000000]  ffffffff81807c80: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
[    0.000000]  ffffffff81807d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[    0.000000] ==================================================================

Fix that by using READ_ONCE_NOCHECK when reading the stack in imprecise
mode.

Fixes: 5d8544e2d0 ("RISC-V: Generic library routines and assembly")
Reported-by: Chathura Rajapaksha <chathura.abeyrathne.lk@gmail.com>
Link: https://lore.kernel.org/all/CAD7mqryDQCYyJ1gAmtMm8SASMWAQ4i103ptTb0f6Oda=tPY2=A@mail.gmail.com/
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20230308091639.602024-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
History 2023-03-09 14:50:35 -08:00
arch riscv: Use READ_ONCE_NOCHECK in imprecise unwinding stack mode 2023-03-09 14:50:35 -08:00
block block-6.3-2023-03-03 2023-03-03 10:21:39 -08:00
certs Kbuild updates for v6.3 2023-02-26 11:53:25 -08:00
crypto Networking changes for 6.3. 2023-02-21 18:24:12 -08:00
Documentation A small set of updates for x86: 2023-03-05 11:27:48 -08:00
drivers This push fixes a regression in the caam driver. 2023-03-05 11:32:30 -08:00
fs 17 hotfixes. Eight are for MM and seven are for other parts of the 2023-03-04 13:32:50 -08:00
include cpumask: re-introduce constant-sized cpumask optimizations 2023-03-05 14:30:34 -08:00
init Kbuild updates for v6.3 2023-02-26 11:53:25 -08:00
io_uring io_uring-6.3-2023-03-03 2023-03-03 10:25:29 -08:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel A set of updates for the interrupt susbsystem: 2023-03-05 11:19:16 -08:00
lib cpumask: re-introduce constant-sized cpumask optimizations 2023-03-05 14:30:34 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: avoid gcc complaint about pointer casting 2023-03-04 14:03:27 -08:00
net nfsd-6.3 fixes: 2023-03-01 11:03:44 -08:00
rust Rust fixes for 6.3-rc1 2023-03-03 14:51:15 -08:00
samples LoongArch changes for v6.3 2023-03-01 09:27:00 -08:00
scripts Remove Intel compiler support 2023-03-05 10:49:37 -08:00
security capability: just use a 'u64' instead of a 'u32[2]' array 2023-03-01 10:01:22 -08:00
sound sound fixes for 6.3-rc1 2023-03-04 10:53:59 -08:00
tools Changes in this cycle were: 2023-03-02 09:45:34 -08:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM/riscv changes for 6.3 2023-02-15 12:33:28 -05:00
.clang-format cpumask: re-introduce constant-sized cpumask optimizations 2023-03-05 14:30:34 -08:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for *.dtso files 2023-02-26 15:28:23 +09:00
.gitignore .gitignore: ignore *.cover and *.mbx 2023-02-05 18:51:22 +09:00
.mailmap mailmap: map Dikshita Agarwal's old address to his current one 2023-03-02 21:54:24 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS There is no particular theme here - mainly quick hits all over the tree. 2023-02-23 17:55:40 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Adding Christian Brauner as VFS co-maintainer. 2023-03-05 11:11:52 -08:00
Makefile Linux 6.3-rc1 2023-03-05 14:52:03 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.