110ecd69a9
p9_release_pages() would attempt to dereference one value past the end of pages[]. This would cause the following crashes: [ 6293.171817] BUG: unable to handle kernel paging request at ffff8807c96f3000 [ 6293.174146] IP: [<ffffffff8412793b>] p9_release_pages+0x3b/0x60 [ 6293.176447] PGD 79c5067 PUD 82c1e3067 PMD 82c197067 PTE 80000007c96f3060 [ 6293.180060] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC [ 6293.180060] Modules linked in: [ 6293.180060] CPU: 62 PID: 174043 Comm: modprobe Tainted: G W 3.10.0-next-20130710-sasha #3954 [ 6293.180060] task: ffff8807b803b000 ti: ffff880787dde000 task.ti: ffff880787dde000 [ 6293.180060] RIP: 0010:[<ffffffff8412793b>] [<ffffffff8412793b>] p9_release_pages+0x3b/0x60 [ 6293.214316] RSP: 0000:ffff880787ddfc28 EFLAGS: 00010202 [ 6293.214316] RAX: 0000000000000001 RBX: ffff8807c96f2ff8 RCX: 0000000000000000 [ 6293.222017] RDX: ffff8807b803b000 RSI: 0000000000000001 RDI: ffffea001c7e3d40 [ 6293.222017] RBP: ffff880787ddfc48 R08: 0000000000000000 R09: 0000000000000000 [ 6293.222017] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001 [ 6293.222017] R13: 0000000000000001 R14: ffff8807cc50c070 R15: ffff8807cc50c070 [ 6293.222017] FS: 00007f572641d700(0000) GS:ffff8807f3600000(0000) knlGS:0000000000000000 [ 6293.256784] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 6293.256784] CR2: ffff8807c96f3000 CR3: 00000007c8e81000 CR4: 00000000000006e0 [ 6293.256784] Stack: [ 6293.256784] ffff880787ddfcc8 ffff880787ddfcc8 0000000000000000 ffff880787ddfcc8 [ 6293.256784] ffff880787ddfd48 ffffffff84128be8 ffff880700000002 0000000000000001 [ 6293.256784] ffff8807b803b000 ffff880787ddfce0 0000100000000000 0000000000000000 [ 6293.256784] Call Trace: [ 6293.256784] [<ffffffff84128be8>] p9_virtio_zc_request+0x598/0x630 [ 6293.256784] [<ffffffff8115c610>] ? wake_up_bit+0x40/0x40 [ 6293.256784] [<ffffffff841209b1>] p9_client_zc_rpc+0x111/0x3a0 [ 6293.256784] [<ffffffff81174b78>] ? sched_clock_cpu+0x108/0x120 [ 6293.256784] [<ffffffff84122a21>] p9_client_read+0xe1/0x2c0 [ 6293.256784] [<ffffffff81708a90>] v9fs_file_read+0x90/0xc0 [ 6293.256784] [<ffffffff812bd073>] vfs_read+0xc3/0x130 [ 6293.256784] [<ffffffff811a78bd>] ? trace_hardirqs_on+0xd/0x10 [ 6293.256784] [<ffffffff812bd5a2>] SyS_read+0x62/0xa0 [ 6293.256784] [<ffffffff841a1a00>] tracesys+0xdd/0xe2 [ 6293.256784] Code: 66 90 48 89 fb 41 89 f5 48 8b 3f 48 85 ff 74 29 85 f6 74 25 45 31 e4 66 0f 1f 84 00 00 00 00 00 e8 eb 14 12 fd 41 ff c4 49 63 c4 <48> 8b 3c c3 48 85 ff 74 05 45 39 e5 75 e7 48 83 c4 08 5b 41 5c [ 6293.256784] RIP [<ffffffff8412793b>] p9_release_pages+0x3b/0x60 [ 6293.256784] RSP <ffff880787ddfc28> [ 6293.256784] CR2: ffff8807c96f3000 [ 6293.256784] ---[ end trace 50822ee72cd360fc ]--- Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
69 lines
2 KiB
C
69 lines
2 KiB
C
/*
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* Copyright IBM Corporation, 2010
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* Author Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of version 2.1 of the GNU Lesser General Public License
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would 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.
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*
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*/
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <net/9p/9p.h>
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#include <net/9p/client.h>
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#include <linux/scatterlist.h>
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#include "trans_common.h"
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/**
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* p9_release_req_pages - Release pages after the transaction.
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*/
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void p9_release_pages(struct page **pages, int nr_pages)
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{
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int i;
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for (i = 0; i < nr_pages; i++)
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if (pages[i])
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put_page(pages[i]);
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}
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EXPORT_SYMBOL(p9_release_pages);
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/**
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* p9_nr_pages - Return number of pages needed to accommodate the payload.
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*/
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int p9_nr_pages(char *data, int len)
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{
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unsigned long start_page, end_page;
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start_page = (unsigned long)data >> PAGE_SHIFT;
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end_page = ((unsigned long)data + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
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return end_page - start_page;
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}
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EXPORT_SYMBOL(p9_nr_pages);
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/**
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* payload_gup - Translates user buffer into kernel pages and
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* pins them either for read/write through get_user_pages_fast().
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* @req: Request to be sent to server.
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* @pdata_off: data offset into the first page after translation (gup).
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* @pdata_len: Total length of the IO. gup may not return requested # of pages.
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* @nr_pages: number of pages to accommodate the payload
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* @rw: Indicates if the pages are for read or write.
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*/
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int p9_payload_gup(char *data, int *nr_pages, struct page **pages, int write)
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{
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int nr_mapped_pages;
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nr_mapped_pages = get_user_pages_fast((unsigned long)data,
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*nr_pages, write, pages);
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if (nr_mapped_pages <= 0)
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return nr_mapped_pages;
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*nr_pages = nr_mapped_pages;
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return 0;
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}
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EXPORT_SYMBOL(p9_payload_gup);
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