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https://github.com/torvalds/linux
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6904817607
most architectures are relying on mmap_sem for write in their arch_setup_additional_pages. If the waiting task gets killed by the oom killer it would block oom_reaper from asynchronous address space reclaim and reduce the chances of timely OOM resolving. Wait for the lock in the killable mode and return with EINTR if the task got killed while waiting. Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Andy Lutomirski <luto@amacapital.net> [x86 vdso] Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
76 lines
1.4 KiB
C
76 lines
1.4 KiB
C
/*
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* Copyright (C) 2011 Richard Weinberger <richrd@nod.at>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/slab.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <asm/page.h>
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#include <asm/elf.h>
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#include <linux/init.h>
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static unsigned int __read_mostly vdso_enabled = 1;
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unsigned long um_vdso_addr;
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extern unsigned long task_size;
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extern char vdso_start[], vdso_end[];
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static struct page **vdsop;
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static int __init init_vdso(void)
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{
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struct page *um_vdso;
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BUG_ON(vdso_end - vdso_start > PAGE_SIZE);
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um_vdso_addr = task_size - PAGE_SIZE;
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vdsop = kmalloc(sizeof(struct page *), GFP_KERNEL);
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if (!vdsop)
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goto oom;
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um_vdso = alloc_page(GFP_KERNEL);
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if (!um_vdso) {
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kfree(vdsop);
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goto oom;
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}
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copy_page(page_address(um_vdso), vdso_start);
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*vdsop = um_vdso;
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return 0;
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oom:
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printk(KERN_ERR "Cannot allocate vdso\n");
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vdso_enabled = 0;
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return -ENOMEM;
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}
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subsys_initcall(init_vdso);
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int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
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{
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int err;
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struct mm_struct *mm = current->mm;
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if (!vdso_enabled)
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return 0;
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if (down_write_killable(&mm->mmap_sem))
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return -EINTR;
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err = install_special_mapping(mm, um_vdso_addr, PAGE_SIZE,
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VM_READ|VM_EXEC|
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VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
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vdsop);
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up_write(&mm->mmap_sem);
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return err;
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}
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