[tip:x86/urgent] x86/mm/numa: Fix kernel stack corruption in numa_init()-> numa_clear_kernel_node_hotplug()
From: tip-bot for Dave Young
Date: Tue Apr 07 2015 - 10:10:25 EST
Commit-ID: 22ef882e6b5bd2bf668d10b1e2be3dc2fc365b99
Gitweb: http://git.kernel.org/tip/22ef882e6b5bd2bf668d10b1e2be3dc2fc365b99
Author: Dave Young <dyoung@xxxxxxxxxx>
AuthorDate: Tue, 7 Apr 2015 21:41:32 +0800
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 7 Apr 2015 16:01:19 +0200
x86/mm/numa: Fix kernel stack corruption in numa_init()->numa_clear_kernel_node_hotplug()
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 corrupted in: ffffffff81d21910
...
[ 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
This is caused by writing over the end of numa mask bitmap
in numa_clear_kernel_node().
numa_clear_kernel_node() tries to set the node id in a mask bitmap,
by iterating all reserved regions and assuming that every region
has a valid nid.
This assumption is not true because there's an exception for some
graphic memory quirks. See trim_snb_memory() in arch/x86/kernel/setup.c
It is easily to reproduce the bug in the kdump kernel because kdump
kernel use pre-reserved memory instead of the 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>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: bhe@xxxxxxxxxx
Cc: qiuxishi@xxxxxxxxxx
Link: http://lkml.kernel.org/r/20150407134132.GA23522@xxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/mm/numa.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index cd4785b..4053bb5 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -482,9 +482,16 @@ static void __init numa_clear_kernel_node_hotplug(void)
&memblock.reserved, mb->nid);
}
- /* Mark all kernel nodes. */
+ /*
+ * Mark all kernel nodes.
+ *
+ * When booting with mem=nn[kMG] or in a 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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