Revision 85bd839983778fcd0c1c043327b14a046e979b39 authored by Gu Zheng on 10 June 2015, 18:14:43 UTC, committed by Linus Torvalds on 10 June 2015, 23:43:43 UTC
Izumi found the following oops when hot re-adding a node: BUG: unable to handle kernel paging request at ffffc90008963690 IP: __wake_up_bit+0x20/0x70 Oops: 0000 [#1] SMP CPU: 68 PID: 1237 Comm: rs:main Q:Reg Not tainted 4.1.0-rc5 #80 Hardware name: FUJITSU PRIMEQUEST2800E/SB, BIOS PRIMEQUEST 2000 Series BIOS Version 1.87 04/28/2015 task: ffff880838df8000 ti: ffff880017b94000 task.ti: ffff880017b94000 RIP: 0010:[<ffffffff810dff80>] [<ffffffff810dff80>] __wake_up_bit+0x20/0x70 RSP: 0018:ffff880017b97be8 EFLAGS: 00010246 RAX: ffffc90008963690 RBX: 00000000003c0000 RCX: 000000000000a4c9 RDX: 0000000000000000 RSI: ffffea101bffd500 RDI: ffffc90008963648 RBP: ffff880017b97c08 R08: 0000000002000020 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8a0797c73800 R13: ffffea101bffd500 R14: 0000000000000001 R15: 00000000003c0000 FS: 00007fcc7ffff700(0000) GS:ffff880874800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffc90008963690 CR3: 0000000836761000 CR4: 00000000001407e0 Call Trace: unlock_page+0x6d/0x70 generic_write_end+0x53/0xb0 xfs_vm_write_end+0x29/0x80 [xfs] generic_perform_write+0x10a/0x1e0 xfs_file_buffered_aio_write+0x14d/0x3e0 [xfs] xfs_file_write_iter+0x79/0x120 [xfs] __vfs_write+0xd4/0x110 vfs_write+0xac/0x1c0 SyS_write+0x58/0xd0 system_call_fastpath+0x12/0x76 Code: 5d c3 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 48 83 ec 20 65 48 8b 04 25 28 00 00 00 48 89 45 f8 31 c0 48 8d 47 48 <48> 39 47 48 48 c7 45 e8 00 00 00 00 48 c7 45 f0 00 00 00 00 48 RIP [<ffffffff810dff80>] __wake_up_bit+0x20/0x70 RSP <ffff880017b97be8> CR2: ffffc90008963690 Reproduce method (re-add a node):: Hot-add nodeA --> remove nodeA --> hot-add nodeA (panic) This seems an use-after-free problem, and the root cause is zone->wait_table was not set to *NULL* after free it in try_offline_node. When hot re-add a node, we will reuse the pgdat of it, so does the zone struct, and when add pages to the target zone, it will init the zone first (including the wait_table) if the zone is not initialized. The judgement of zone initialized is based on zone->wait_table: static inline bool zone_is_initialized(struct zone *zone) { return !!zone->wait_table; } so if we do not set the zone->wait_table to *NULL* after free it, the memory hotplug routine will skip the init of new zone when hot re-add the node, and the wait_table still points to the freed memory, then we will access the invalid address when trying to wake up the waiting people after the i/o operation with the page is done, such as mentioned above. Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com> Reported-by: Taku Izumi <izumi.taku@jp.fujitsu.com> Reviewed by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 5879ae5
memneq.c
/*
* Constant-time equality testing of memory regions.
*
* Authors:
*
* James Yonan <james@openvpn.net>
* Daniel Borkmann <dborkman@redhat.com>
*
* This file is provided under a dual BSD/GPLv2 license. When using or
* redistributing this file, you may do so under either license.
*
* GPL LICENSE SUMMARY
*
* Copyright(c) 2013 OpenVPN Technologies, Inc. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
* The full GNU General Public License is included in this distribution
* in the file called LICENSE.GPL.
*
* BSD LICENSE
*
* Copyright(c) 2013 OpenVPN Technologies, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of OpenVPN Technologies nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <crypto/algapi.h>
#ifndef __HAVE_ARCH_CRYPTO_MEMNEQ
/* Generic path for arbitrary size */
static inline unsigned long
__crypto_memneq_generic(const void *a, const void *b, size_t size)
{
unsigned long neq = 0;
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
while (size >= sizeof(unsigned long)) {
neq |= *(unsigned long *)a ^ *(unsigned long *)b;
OPTIMIZER_HIDE_VAR(neq);
a += sizeof(unsigned long);
b += sizeof(unsigned long);
size -= sizeof(unsigned long);
}
#endif /* CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS */
while (size > 0) {
neq |= *(unsigned char *)a ^ *(unsigned char *)b;
OPTIMIZER_HIDE_VAR(neq);
a += 1;
b += 1;
size -= 1;
}
return neq;
}
/* Loop-free fast-path for frequently used 16-byte size */
static inline unsigned long __crypto_memneq_16(const void *a, const void *b)
{
unsigned long neq = 0;
#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
if (sizeof(unsigned long) == 8) {
neq |= *(unsigned long *)(a) ^ *(unsigned long *)(b);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned long *)(a+8) ^ *(unsigned long *)(b+8);
OPTIMIZER_HIDE_VAR(neq);
} else if (sizeof(unsigned int) == 4) {
neq |= *(unsigned int *)(a) ^ *(unsigned int *)(b);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned int *)(a+4) ^ *(unsigned int *)(b+4);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned int *)(a+8) ^ *(unsigned int *)(b+8);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned int *)(a+12) ^ *(unsigned int *)(b+12);
OPTIMIZER_HIDE_VAR(neq);
} else
#endif /* CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS */
{
neq |= *(unsigned char *)(a) ^ *(unsigned char *)(b);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned char *)(a+1) ^ *(unsigned char *)(b+1);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned char *)(a+2) ^ *(unsigned char *)(b+2);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned char *)(a+3) ^ *(unsigned char *)(b+3);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned char *)(a+4) ^ *(unsigned char *)(b+4);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned char *)(a+5) ^ *(unsigned char *)(b+5);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned char *)(a+6) ^ *(unsigned char *)(b+6);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned char *)(a+7) ^ *(unsigned char *)(b+7);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned char *)(a+8) ^ *(unsigned char *)(b+8);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned char *)(a+9) ^ *(unsigned char *)(b+9);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned char *)(a+10) ^ *(unsigned char *)(b+10);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned char *)(a+11) ^ *(unsigned char *)(b+11);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned char *)(a+12) ^ *(unsigned char *)(b+12);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned char *)(a+13) ^ *(unsigned char *)(b+13);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned char *)(a+14) ^ *(unsigned char *)(b+14);
OPTIMIZER_HIDE_VAR(neq);
neq |= *(unsigned char *)(a+15) ^ *(unsigned char *)(b+15);
OPTIMIZER_HIDE_VAR(neq);
}
return neq;
}
/* Compare two areas of memory without leaking timing information,
* and with special optimizations for common sizes. Users should
* not call this function directly, but should instead use
* crypto_memneq defined in crypto/algapi.h.
*/
noinline unsigned long __crypto_memneq(const void *a, const void *b,
size_t size)
{
switch (size) {
case 16:
return __crypto_memneq_16(a, b);
default:
return __crypto_memneq_generic(a, b, size);
}
}
EXPORT_SYMBOL(__crypto_memneq);
#endif /* __HAVE_ARCH_CRYPTO_MEMNEQ */
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