Revision 56ee254d23c59fd48fb6f192d79858f60cfe2bf6 authored by David Sterba on 27 October 2021, 08:42:27 UTC, committed by David Sterba on 29 October 2021, 11:02:50 UTC
This reverts commit bbaf9715f3f5b5ff0de71da91fcc34ee9c198ed8. The kmaps in compression code are still needed and cause crashes on 32bit machines (ARM, x86). Reproducible eg. by running fstest btrfs/004 with enabled LZO or ZSTD compression. Example stacktrace with ZSTD on a 32bit ARM machine: Unable to handle kernel NULL pointer dereference at virtual address 00000000 pgd = c4159ed3 [00000000] *pgd=00000000 Internal error: Oops: 5 [#1] PREEMPT SMP ARM Modules linked in: CPU: 0 PID: 210 Comm: kworker/u2:3 Not tainted 5.14.0-rc79+ #12 Hardware name: Allwinner sun4i/sun5i Families Workqueue: btrfs-delalloc btrfs_work_helper PC is at mmiocpy+0x48/0x330 LR is at ZSTD_compressStream_generic+0x15c/0x28c (mmiocpy) from [<c0629648>] (ZSTD_compressStream_generic+0x15c/0x28c) (ZSTD_compressStream_generic) from [<c06297dc>] (ZSTD_compressStream+0x64/0xa0) (ZSTD_compressStream) from [<c049444c>] (zstd_compress_pages+0x170/0x488) (zstd_compress_pages) from [<c0496798>] (btrfs_compress_pages+0x124/0x12c) (btrfs_compress_pages) from [<c043c068>] (compress_file_range+0x3c0/0x834) (compress_file_range) from [<c043c4ec>] (async_cow_start+0x10/0x28) (async_cow_start) from [<c0475c3c>] (btrfs_work_helper+0x100/0x230) (btrfs_work_helper) from [<c014ef68>] (process_one_work+0x1b4/0x418) (process_one_work) from [<c014f210>] (worker_thread+0x44/0x524) (worker_thread) from [<c0156aa4>] (kthread+0x180/0x1b0) (kthread) from [<c0100150>] Link: https://lore.kernel.org/all/CAJCQCtT+OuemovPO7GZk8Y8=qtOObr0XTDp8jh4OHD6y84AFxw@mail.gmail.com/ Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=214839 Signed-off-by: David Sterba <dsterba@suse.com>
1 parent 3a60f65
rodata_test.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* rodata_test.c: functional test for mark_rodata_ro function
*
* (C) Copyright 2008 Intel Corporation
* Author: Arjan van de Ven <arjan@linux.intel.com>
*/
#define pr_fmt(fmt) "rodata_test: " fmt
#include <linux/rodata_test.h>
#include <linux/uaccess.h>
#include <asm/sections.h>
static const int rodata_test_data = 0xC3;
void rodata_test(void)
{
unsigned long start, end;
int zero = 0;
/* test 1: read the value */
/* If this test fails, some previous testrun has clobbered the state */
if (!rodata_test_data) {
pr_err("test 1 fails (start data)\n");
return;
}
/* test 2: write to the variable; this should fault */
if (!copy_to_kernel_nofault((void *)&rodata_test_data,
(void *)&zero, sizeof(zero))) {
pr_err("test data was not read only\n");
return;
}
/* test 3: check the value hasn't changed */
if (rodata_test_data == zero) {
pr_err("test data was changed\n");
return;
}
/* test 4: check if the rodata section is PAGE_SIZE aligned */
start = (unsigned long)__start_rodata;
end = (unsigned long)__end_rodata;
if (start & (PAGE_SIZE - 1)) {
pr_err("start of .rodata is not page size aligned\n");
return;
}
if (end & (PAGE_SIZE - 1)) {
pr_err("end of .rodata is not page size aligned\n");
return;
}
pr_info("all tests were successful\n");
}
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