From mboxrd@z Thu Jan 1 00:00:00 1970 From: hanjun.guo@linaro.org (Hanjun Guo) Date: Fri, 28 Oct 2016 09:50:16 +0800 Subject: [PATCH v2 1/2] arm64/numa: fix pcpu_cpu_distance() to get correct CPU proximity In-Reply-To: <1477037636-10077-1-git-send-email-guohanjun@huawei.com> References: <1477037636-10077-1-git-send-email-guohanjun@huawei.com> Message-ID: <832317c9-c341-14ed-df2d-f314302030e2@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org +Cc Robert, David. On 2016/10/21 16:13, Hanjun Guo wrote: > From: Yisheng Xie > > The pcpu_build_alloc_info() function group CPUs according to their > proximity, by call callback function @cpu_distance_fn from different > ARCHs. > > For arm64 the callback of @cpu_distance_fn is > pcpu_cpu_distance(from, to) > -> node_distance(from, to) > The @from and @to for function node_distance() should be nid. > > However, pcpu_cpu_distance() in arch/arm64/mm/numa.c just past the > cpu id for @from and @to, and didn't convert to numa node id. > > For this incorrect cpu proximity get from ARCH, it may cause each CPU > in one group and make group_cnt out of bound: > > setup_per_cpu_areas() > pcpu_embed_first_chunk() > pcpu_build_alloc_info() > in pcpu_build_alloc_info, since cpu_distance_fn will return > REMOTE_DISTANCE if we pass cpu ids (0,1,2...), so > cpu_distance_fn(cpu, tcpu) > LOCAL_DISTANCE will wrongly be ture. > > This may results in triggering the BUG_ON(unit != nr_units) later: > > [ 0.000000] kernel BUG at mm/percpu.c:1916! > [ 0.000000] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP > [ 0.000000] Modules linked in: > [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.9.0-rc1-00003-g14155ca-dirty #26 > [ 0.000000] Hardware name: Hisilicon Hi1616 Evaluation Board (DT) > [ 0.000000] task: ffff000008d6e900 task.stack: ffff000008d60000 > [ 0.000000] PC is at pcpu_embed_first_chunk+0x420/0x704 > [ 0.000000] LR is at pcpu_embed_first_chunk+0x3bc/0x704 > [ 0.000000] pc : [] lr : [] pstate: 800000c5 > [ 0.000000] sp : ffff000008d63eb0 > [ 0.000000] x29: ffff000008d63eb0 [ 0.000000] x28: 0000000000000000 > [ 0.000000] x27: 0000000000000040 [ 0.000000] x26: ffff8413fbfcef00 > [ 0.000000] x25: 0000000000000042 [ 0.000000] x24: 0000000000000042 > [ 0.000000] x23: 0000000000001000 [ 0.000000] x22: 0000000000000046 > [ 0.000000] x21: 0000000000000001 [ 0.000000] x20: ffff000008cb3bc8 > [ 0.000000] x19: ffff8413fbfcf570 [ 0.000000] x18: 0000000000000000 > [ 0.000000] x17: ffff000008e49ae0 [ 0.000000] x16: 0000000000000003 > [ 0.000000] x15: 000000000000001e [ 0.000000] x14: 0000000000000004 > [ 0.000000] x13: 0000000000000000 [ 0.000000] x12: 000000000000006f > [ 0.000000] x11: 00000413fbffff00 [ 0.000000] x10: 0000000000000004 > [ 0.000000] x9 : 0000000000000000 [ 0.000000] x8 : 0000000000000001 > [ 0.000000] x7 : ffff8413fbfcf63c [ 0.000000] x6 : ffff000008d65d28 > [ 0.000000] x5 : ffff000008d65e50 [ 0.000000] x4 : 0000000000000000 > [ 0.000000] x3 : ffff000008cb3cc8 [ 0.000000] x2 : 0000000000000040 > [ 0.000000] x1 : 0000000000000040 [ 0.000000] x0 : 0000000000000000 > [...] > [ 0.000000] Call trace: > [ 0.000000] Exception stack(0xffff000008d63ce0 to 0xffff000008d63e10) > [ 0.000000] 3ce0: ffff8413fbfcf570 0001000000000000 ffff000008d63eb0 ffff000008c754f4 > [ 0.000000] 3d00: ffff000008d63d50 ffff0000081af210 00000413fbfff010 0000000000001000 > [ 0.000000] 3d20: ffff000008d63d50 ffff0000081af220 00000413fbfff010 0000000000001000 > [ 0.000000] 3d40: 00000413fbfcef00 0000000000000004 ffff000008d63db0 ffff0000081af390 > [ 0.000000] 3d60: 00000413fbfcef00 0000000000001000 0000000000000000 0000000000001000 > [ 0.000000] 3d80: 0000000000000000 0000000000000040 0000000000000040 ffff000008cb3cc8 > [ 0.000000] 3da0: 0000000000000000 ffff000008d65e50 ffff000008d65d28 ffff8413fbfcf63c > [ 0.000000] 3dc0: 0000000000000001 0000000000000000 0000000000000004 00000413fbffff00 > [ 0.000000] 3de0: 000000000000006f 0000000000000000 0000000000000004 000000000000001e > [ 0.000000] 3e00: 0000000000000003 ffff000008e49ae0 > [ 0.000000] [] pcpu_embed_first_chunk+0x420/0x704 > [ 0.000000] [] setup_per_cpu_areas+0x38/0xc8 > [ 0.000000] [] start_kernel+0x10c/0x390 > [ 0.000000] [] __primary_switched+0x5c/0x64 > [ 0.000000] Code: b8018660 17ffffd7 6b16037f 54000080 (d4210000) > [ 0.000000] ---[ end trace 0000000000000000 ]--- > [ 0.000000] Kernel panic - not syncing: Attempted to kill the idle task! > > Fix by getting cpu's node id with early_cpu_to_node() then pass it > to node_distance() as the original intention. > > Fixes: 7af3a0a99252 ("arm64/numa: support HAVE_SETUP_PER_CPU_AREA") > Signed-off-by: Yisheng Xie > Signed-off-by: Hanjun Guo > Cc: Catalin Marinas > Cc: Lorenzo Pieralisi > Cc: Will Deacon > Cc: Zhen Lei > --- > arch/arm64/mm/numa.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c > index 778a985..9a71d06 100644 > --- a/arch/arm64/mm/numa.c > +++ b/arch/arm64/mm/numa.c > @@ -147,7 +147,7 @@ static int __init early_cpu_to_node(int cpu) > > static int __init pcpu_cpu_distance(unsigned int from, unsigned int to) > { > - return node_distance(from, to); > + return node_distance(early_cpu_to_node(from), early_cpu_to_node(to)); > } > > static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, >