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0b0ad2541d
free_pages() performs a parameter null check inside therefore remove double zero check here. Signed-off-by: Shaojie Dong <quic_shaojied@quicinc.com> Link: https://patch.msgid.link/20241025-upstream_branch-v5-1-b8998beb2c64@quicinc.com Signed-off-by: Johannes Berg <johannes.berg@intel.com>
72 lines
1.7 KiB
C
72 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
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* Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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*/
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#include <linux/mm.h>
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#include <linux/sched/signal.h>
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#include <linux/slab.h>
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#include <asm/pgalloc.h>
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#include <asm/sections.h>
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#include <asm/mmu_context.h>
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#include <as-layout.h>
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#include <os.h>
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#include <skas.h>
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#include <stub-data.h>
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/* Ensure the stub_data struct covers the allocated area */
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static_assert(sizeof(struct stub_data) == STUB_DATA_PAGES * UM_KERN_PAGE_SIZE);
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int init_new_context(struct task_struct *task, struct mm_struct *mm)
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{
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struct mm_id *new_id = &mm->context.id;
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unsigned long stack = 0;
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int ret = -ENOMEM;
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stack = __get_free_pages(GFP_KERNEL | __GFP_ZERO, ilog2(STUB_DATA_PAGES));
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if (stack == 0)
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goto out;
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new_id->stack = stack;
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block_signals_trace();
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new_id->pid = start_userspace(stack);
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unblock_signals_trace();
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if (new_id->pid < 0) {
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ret = new_id->pid;
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goto out_free;
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}
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/* Ensure the new MM is clean and nothing unwanted is mapped */
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unmap(new_id, 0, STUB_START);
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return 0;
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out_free:
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free_pages(new_id->stack, ilog2(STUB_DATA_PAGES));
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out:
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return ret;
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}
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void destroy_context(struct mm_struct *mm)
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{
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struct mm_context *mmu = &mm->context;
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/*
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* If init_new_context wasn't called, this will be
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* zero, resulting in a kill(0), which will result in the
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* whole UML suddenly dying. Also, cover negative and
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* 1 cases, since they shouldn't happen either.
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*/
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if (mmu->id.pid < 2) {
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printk(KERN_ERR "corrupt mm_context - pid = %d\n",
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mmu->id.pid);
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return;
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}
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os_kill_ptraced_process(mmu->id.pid, 1);
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free_pages(mmu->id.stack, ilog2(STUB_DATA_PAGES));
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}
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