3faa3d9a30
The hfi1 driver registers a mmu_notifier callback when /dev/hfi1_* is opened, and unregisters it when the device is closed. The driver incorrectly assumes that the close will always happen from the same context as the open. In particular, closes due to SIGKILL or OOM killer activity may happen from a different context. In these cases, the wrong mm is passed to mmu_notifier_unregister(), which causes improper reference counting for the victim mm, and eventual memory corruption. Preserve the mm for all open file descriptors and use this mm rather than current->mm for memory operations for the lifetime of that fd. Note: this patch leaves 1 use of current->mm in place. This use is removed in a follow on patch because other functional changes were required prior to that use being removed. If registration fails, there is no reason to keep the handler object around. Free the handler object rather than add it to the list to prevent any mmu_notifier operations, including unregister, when registration fails. Suggested-by: Jim Foraker <foraker1@llnl.gov> Reviewed-by: Dean Luick <dean.luick@intel.com> Signed-off-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
137 lines
4.6 KiB
C
137 lines
4.6 KiB
C
/*
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* Copyright(c) 2015, 2016 Intel Corporation.
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*
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* This file is provided under a dual BSD/GPLv2 license. When using or
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* redistributing this file, you may do so under either license.
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*
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* GPL LICENSE SUMMARY
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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 version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* BSD LICENSE
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* - Neither the name of Intel Corporation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <linux/device.h>
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#include <linux/module.h>
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#include "hfi.h"
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static unsigned long cache_size = 256;
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module_param(cache_size, ulong, S_IRUGO | S_IWUSR);
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MODULE_PARM_DESC(cache_size, "Send and receive side cache size limit (in MB)");
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/*
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* Determine whether the caller can pin pages.
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*
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* This function should be used in the implementation of buffer caches.
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* The cache implementation should call this function prior to attempting
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* to pin buffer pages in order to determine whether they should do so.
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* The function computes cache limits based on the configured ulimit and
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* cache size. Use of this function is especially important for caches
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* which are not limited in any other way (e.g. by HW resources) and, thus,
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* could keeping caching buffers.
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*
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*/
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bool hfi1_can_pin_pages(struct hfi1_devdata *dd, struct mm_struct *mm,
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u32 nlocked, u32 npages)
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{
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unsigned long ulimit = rlimit(RLIMIT_MEMLOCK), pinned, cache_limit,
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size = (cache_size * (1UL << 20)); /* convert to bytes */
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unsigned usr_ctxts = dd->num_rcv_contexts - dd->first_user_ctxt;
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bool can_lock = capable(CAP_IPC_LOCK);
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/*
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* Calculate per-cache size. The calculation below uses only a quarter
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* of the available per-context limit. This leaves space for other
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* pinning. Should we worry about shared ctxts?
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*/
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cache_limit = (ulimit / usr_ctxts) / 4;
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/* If ulimit isn't set to "unlimited" and is smaller than cache_size. */
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if (ulimit != (-1UL) && size > cache_limit)
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size = cache_limit;
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/* Convert to number of pages */
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size = DIV_ROUND_UP(size, PAGE_SIZE);
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down_read(&mm->mmap_sem);
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pinned = mm->pinned_vm;
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up_read(&mm->mmap_sem);
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/* First, check the absolute limit against all pinned pages. */
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if (pinned + npages >= ulimit && !can_lock)
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return false;
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return ((nlocked + npages) <= size) || can_lock;
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}
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int hfi1_acquire_user_pages(struct mm_struct *mm, unsigned long vaddr, size_t npages,
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bool writable, struct page **pages)
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{
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int ret;
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ret = get_user_pages_fast(vaddr, npages, writable, pages);
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if (ret < 0)
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return ret;
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down_write(&mm->mmap_sem);
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mm->pinned_vm += ret;
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up_write(&mm->mmap_sem);
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return ret;
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}
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void hfi1_release_user_pages(struct mm_struct *mm, struct page **p,
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size_t npages, bool dirty)
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{
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size_t i;
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for (i = 0; i < npages; i++) {
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if (dirty)
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set_page_dirty_lock(p[i]);
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put_page(p[i]);
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}
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if (mm) { /* during close after signal, mm can be NULL */
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down_write(&mm->mmap_sem);
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mm->pinned_vm -= npages;
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up_write(&mm->mmap_sem);
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}
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}
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