[PATCH V2] x86/numa: kernel stack corruption fix
From: Dave Young
Date: Tue Apr 07 2015 - 09:41:44 EST
I got below kernel panic during kdump test on Thinkpad T420 laptop:
[ 0.000000] No NUMA configuration found
[ 0.000000] Faking a node at [mem 0x0000000000000000-0x0000000037ba4fff]
[ 0.000000] Kernel panic - not syncing: stack-protector: Kernel stack is cor
upted in: ffffffff81d21910 r
[ 0.000000]
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.0.0-rc6+ #44
[ 0.000000] Hardware name: LENOVO 4236NUC/4236NUC, BIOS 83ET76WW (1.46 ) 07/
5/2013 0
[ 0.000000] 0000000000000000 c70296ddd809e4f6 ffffffff81b67ce8 ffffffff817c
a26 2
[ 0.000000] 0000000000000000 ffffffff81a61c90 ffffffff81b67d68 ffffffff817b
8d2 c
[ 0.000000] 0000000000000010 ffffffff81b67d78 ffffffff81b67d18 c70296ddd809
4f6 e
[ 0.000000] Call Trace:
[ 0.000000] [<ffffffff817c2a26>] dump_stack+0x45/0x57
[ 0.000000] [<ffffffff817bc8d2>] panic+0xd0/0x204
[ 0.000000] [<ffffffff81d21910>] ? numa_clear_kernel_node_hotplug+0xe6/0xf2
[ 0.000000] [<ffffffff8107741b>] __stack_chk_fail+0x1b/0x20
[ 0.000000] [<ffffffff81d21910>] numa_clear_kernel_node_hotplug+0xe6/0xf2
[ 0.000000] [<ffffffff81d21e5d>] numa_init+0x1a5/0x520
[ 0.000000] [<ffffffff81d222b1>] x86_numa_init+0x19/0x3d
[ 0.000000] [<ffffffff81d22460>] initmem_init+0x9/0xb
[ 0.000000] [<ffffffff81d0d00c>] setup_arch+0x94f/0xc82
[ 0.000000] [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120
[ 0.000000] [<ffffffff817bd0bb>] ? printk+0x55/0x6b
[ 0.000000] [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120
[ 0.000000] [<ffffffff81d05d9b>] start_kernel+0xe8/0x4d6
[ 0.000000] [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120
[ 0.000000] [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120
[ 0.000000] [<ffffffff81d055ee>] x86_64_start_reservations+0x2a/0x2c
[ 0.000000] [<ffffffff81d05751>] x86_64_start_kernel+0x161/0x184
[ 0.000000] ---[ end Kernel panic - not syncing: stack-protector: Kernel sta
k is corrupted in: ffffffff81d21910 c
[ 0.000000]
PANIC: early exception 0d rip 10:ffffffff8105d2a6 error 7eb cr2 ffff8800371dd00
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.0.0-rc6+ #44 0
[ 0.000000] Hardware name: LENOVO 4236NUC/4236NUC, BIOS 83ET76WW (1.46 ) 07/
5/2013 0
[ 0.000000] 0000000000000000 c70296ddd809e4f6 ffffffff81b67c60 ffffffff817c
a26 2
[ 0.000000] 0000000000000096 ffffffff81a61c90 ffffffff81b67d68 fffffff00000
084 0000000000000a0d 0000000000000a00 0
[ 0.000000] Call Trace:
[ 0.000000] [<ffffffff817c2a26>] dump_stack+0x45/0x57
[ 0.000000] [<ffffffff81d051b0>] early_idt_handler+0x90/0xb7
[ 0.000000] [<ffffffff8105d2a6>] ? native_irq_enable+0x6/0x10
[ 0.000000] [<ffffffff817bc9c5>] ? panic+0x1c3/0x204
[ 0.000000] [<ffffffff81d21910>] ? numa_clear_kernel_node_hotplug+0xe6/0xf2
[ 0.000000] [<ffffffff8107741b>] __stack_chk_fail+0x1b/0x20
[ 0.000000] [<ffffffff81d21910>] numa_clear_kernel_node_hotplug+0xe6/0xf2
[ 0.000000] [<ffffffff81d21e5d>] numa_init+0x1a5/0x520
[ 0.000000] [<ffffffff81d222b1>] x86_numa_init+0x19/0x3d
[ 0.000000] [<ffffffff81d22460>] initmem_init+0x9/0xb
[ 0.000000] [<ffffffff81d0d00c>] setup_arch+0x94f/0xc82
[ 0.000000] [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120
[ 0.000000] [<ffffffff817bd0bb>] ? printk+0x55/0x6b
[ 0.000000] [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120
[ 0.000000] [<ffffffff81d05d9b>] start_kernel+0xe8/0x4d6
[ 0.000000] [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120
[ 0.000000] [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120
[ 0.000000] [<ffffffff81d055ee>] x86_64_start_reservations+0x2a/0x2c
[ 0.000000] [<ffffffff81d05751>] x86_64_start_kernel+0x161/0x184
[ 0.000000] RIP 0x46
This is caused by writing over end of numa mask bitmap.
numa_clear_kernel_node try to set node id in a mask bitmap, it iterating all
reserved region and assume every regions have valid nid. It is not true because
There's an exception for some graphic memory quirks.
See function trim_snb_memory in arch/x86/kernel/setup.c
It is easily to reproduce the bug in kdump kernel because kdump kernel use
pre-reserved memory instead of whole memory, but kexec pass other reserved
memory ranges to 2nd kernel as well. like below in my test:
kdump kernel ram 0x2d000000 - 0x37bfffff
One of the reserved regions: 0x40000000 - 0x40100000 which includes 0x40004000,
a page excluded in trim_snb_memory. For this memblock reserved region the nid
is not set, it is still default value MAX_NUMNODES. later node_set will set bit
MAX_NUMNODES thus stack corruption happen.
This also happens when booting with mem= kernel commandline during my test.
Fixing it by adding a check, do not call node_set in case nid is MAX_NUMNODES.
Signed-off-by: Dave Young <dyoung@xxxxxxxxxx>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
---
arch/x86/mm/numa.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
--- linux.orig/arch/x86/mm/numa.c
+++ linux/arch/x86/mm/numa.c
@@ -482,9 +482,16 @@ static void __init numa_clear_kernel_nod
&memblock.reserved, mb->nid);
}
- /* Mark all kernel nodes. */
+ /*
+ * Mark all kernel nodes.
+ *
+ * In case booting with mem=nn[kMG] or in kdump kernel, numa_meminfo
+ * may not include all the memblock.reserved memory ranges because
+ * trim_snb_memory() reserves specific pages for Sandy Bridge graphics.
+ */
for_each_memblock(reserved, r)
- node_set(r->nid, numa_kernel_nodes);
+ if (r->nid != MAX_NUMNODES)
+ node_set(r->nid, numa_kernel_nodes);
/* Clear MEMBLOCK_HOTPLUG flag for memory in kernel nodes. */
for (i = 0; i < numa_meminfo.nr_blks; i++) {
--
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