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>
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clk-moxart.c
/*
* MOXA ART SoCs clock driver.
*
* Copyright (C) 2013 Jonas Jensen
*
* Jonas Jensen <jonas.jensen@gmail.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/clk-provider.h>
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/clkdev.h>
void __init moxart_of_pll_clk_init(struct device_node *node)
{
static void __iomem *base;
struct clk *clk, *ref_clk;
unsigned int mul;
const char *name = node->name;
const char *parent_name;
of_property_read_string(node, "clock-output-names", &name);
parent_name = of_clk_get_parent_name(node, 0);
base = of_iomap(node, 0);
if (!base) {
pr_err("%s: of_iomap failed\n", node->full_name);
return;
}
mul = readl(base + 0x30) >> 3 & 0x3f;
iounmap(base);
ref_clk = of_clk_get(node, 0);
if (IS_ERR(ref_clk)) {
pr_err("%s: of_clk_get failed\n", node->full_name);
return;
}
clk = clk_register_fixed_factor(NULL, name, parent_name, 0, mul, 1);
if (IS_ERR(clk)) {
pr_err("%s: failed to register clock\n", node->full_name);
return;
}
clk_register_clkdev(clk, NULL, name);
of_clk_add_provider(node, of_clk_src_simple_get, clk);
}
CLK_OF_DECLARE(moxart_pll_clock, "moxa,moxart-pll-clock",
moxart_of_pll_clk_init);
void __init moxart_of_apb_clk_init(struct device_node *node)
{
static void __iomem *base;
struct clk *clk, *pll_clk;
unsigned int div, val;
unsigned int div_idx[] = { 2, 3, 4, 6, 8};
const char *name = node->name;
const char *parent_name;
of_property_read_string(node, "clock-output-names", &name);
parent_name = of_clk_get_parent_name(node, 0);
base = of_iomap(node, 0);
if (!base) {
pr_err("%s: of_iomap failed\n", node->full_name);
return;
}
val = readl(base + 0xc) >> 4 & 0x7;
iounmap(base);
if (val > 4)
val = 0;
div = div_idx[val] * 2;
pll_clk = of_clk_get(node, 0);
if (IS_ERR(pll_clk)) {
pr_err("%s: of_clk_get failed\n", node->full_name);
return;
}
clk = clk_register_fixed_factor(NULL, name, parent_name, 0, 1, div);
if (IS_ERR(clk)) {
pr_err("%s: failed to register clock\n", node->full_name);
return;
}
clk_register_clkdev(clk, NULL, name);
of_clk_add_provider(node, of_clk_src_simple_get, clk);
}
CLK_OF_DECLARE(moxart_apb_clock, "moxa,moxart-apb-clock",
moxart_of_apb_clk_init);
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