On 2015/4/1 16:21, Xishi Qiu wrote: > On 2015/4/1 15:41, Dave Young wrote: > >> On 04/01/15 at 03:27pm, Xishi Qiu wrote: >>> On 2015/4/1 13:11, Dave Young wrote: >>> >>>> Ccing Xishi Qiu who wrote the clear_kernel_node_hotplug code. >>>> >>>> On 04/01/15 at 12:53pm, Dave Young wrote: >>>>> 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 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 >>>>> prereserved 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 >>>>> >>>>> The above reserved region 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 callback will set bit >>>>> MAX_NUMNODES in nodemask bitmap thus stack corruption happen. >>>>> >>> >>> Hi Dave, >>> >>> Is it means, first reserved region 0x40000000 - 0x40100000, then boot the >>> kdump >>> kernel, so this region is not include in "numa_meminfo", and >>> memblock.reserved >>> (0x40004000) is still MAX_NUMNODES from trim_snb_memory(). >> >> Right, btw, I booted kdump kernel with numa=off for saving memory. >> >> I suspect it will also be reproduced with mem=XYZ with normal kernel. >> > > cc Tang Chen, numa_clear_kernel_node_hotplug() is original written by him. > > Hi Dave, > I tested the problem, and find the kdump's "numa_meminfo" is the same as the > first > kernel. I did not set "numa=off" in kdump kernel, maybe this will lead to the > difference of "numa_meminfo" >
Hi Dave, I find the reason, it's "dummy_numa_init() -> numa_add_memblk(0, 0, PFN_PHYS(max_pfn));", this lead to the difference of "numa_meminfo" when set "numa=off". However we should fix the bug when set "numa=off". Thanks, Xishi Qiu -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
