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" Thanks, Xishi Qiu >> >> numa_clear_kernel_node_hotplug >> { >> ... >> for (i = 0; i < numa_meminfo.nr_blks; i++) { >> struct numa_memblk *mb = &numa_meminfo.blk[i]; >> >> memblock_set_node(mb->start, mb->end - mb->start, >> &memblock.reserved, mb->nid); // this will >> not reset 0x40004000's node, right? >> } >> ... >> } >> >> 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/