Messages in this thread Patch in this message | | | From | Pingfan Liu <> | Subject | [PATCH 2/2] x86/numa: instance all parsed numa node | Date | Fri, 5 Jul 2019 12:15:43 +0800 |
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I hit a bug on an AMD machine, with kexec -l nr_cpus=4 option. nr_cpus option is used to speed up kdump process, so it is not a rare case.
It turns out that some pgdat is not instanced when specifying nr_cpus, e.g, on x86, not initialized by init_cpu_to_node()->init_memory_less_node(). But device->numa_node info is used as preferred_nid param for __alloc_pages_nodemask(), which causes NULL reference ac->zonelist = node_zonelist(preferred_nid, gfp_mask);
Although this bug is detected on x86, it should affect all archs, where a machine with a numa-node having no memory, if nr_cpus prevents the instance of the node, and the device on the node tries to allocate memory with device->numa_node info.
The patch takes the way by instancing all parsed numa node on x86. (for more detail, please refer to section I and II)
I. Notes about the crashing info: -1 kexec -l with nr_cpus=4 -2 system info NUMA node0 CPU(s): 0,8,16,24 NUMA node1 CPU(s): 2,10,18,26 NUMA node2 CPU(s): 4,12,20,28 NUMA node3 CPU(s): 6,14,22,30 NUMA node4 CPU(s): 1,9,17,25 NUMA node5 CPU(s): 3,11,19,27 NUMA node6 CPU(s): 5,13,21,29 NUMA node7 CPU(s): 7,15,23,31 -3 panic stack [...] [ 5.721547] atomic64_test: passed for x86-64 platform with CX8 and with SSE [ 5.729187] pcieport 0000:00:01.1: Signaling PME with IRQ 34 [ 5.735187] pcieport 0000:00:01.2: Signaling PME with IRQ 35 [ 5.741168] pcieport 0000:00:01.3: Signaling PME with IRQ 36 [ 5.747189] pcieport 0000:00:07.1: Signaling PME with IRQ 37 [ 5.754061] pcieport 0000:00:08.1: Signaling PME with IRQ 39 [ 5.760727] pcieport 0000:20:07.1: Signaling PME with IRQ 40 [ 5.766955] pcieport 0000:20:08.1: Signaling PME with IRQ 42 [ 5.772742] BUG: unable to handle kernel paging request at 0000000000002088 [ 5.773618] PGD 0 P4D 0 [ 5.773618] Oops: 0000 [#1] SMP NOPTI [ 5.773618] CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.20.0-rc1+ #3 [ 5.773618] Hardware name: Dell Inc. PowerEdge R7425/02MJ3T, BIOS 1.4.3 06/29/2018 [ 5.773618] RIP: 0010:__alloc_pages_nodemask+0xe2/0x2a0 [ 5.773618] Code: 00 00 44 89 ea 80 ca 80 41 83 f8 01 44 0f 44 ea 89 da c1 ea 08 83 e2 01 88 54 24 20 48 8b 54 24 08 48 85 d2 0f 85 46 01 00 00 <3b> 77 08 0f 82 3d 01 00 00 48 89 f8 44 89 ea 48 89 e1 44 89 e6 89 [ 5.773618] RSP: 0018:ffffaa600005fb20 EFLAGS: 00010246 [ 5.773618] RAX: 0000000000000000 RBX: 00000000006012c0 RCX: 0000000000000000 [ 5.773618] RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000002080 [ 5.773618] RBP: 00000000006012c0 R08: 0000000000000000 R09: 0000000000000002 [ 5.773618] R10: 00000000006080c0 R11: 0000000000000002 R12: 0000000000000000 [ 5.773618] R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000002 [ 5.773618] FS: 0000000000000000(0000) GS:ffff8c69afe00000(0000) knlGS:0000000000000000 [ 5.773618] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 5.773618] CR2: 0000000000002088 CR3: 000000087e00a000 CR4: 00000000003406e0 [ 5.773618] Call Trace: [ 5.773618] new_slab+0xa9/0x570 [ 5.773618] ___slab_alloc+0x375/0x540 [ 5.773618] ? pinctrl_bind_pins+0x2b/0x2a0 [ 5.773618] __slab_alloc+0x1c/0x38 [ 5.773618] __kmalloc_node_track_caller+0xc8/0x270 [ 5.773618] ? pinctrl_bind_pins+0x2b/0x2a0 [ 5.773618] devm_kmalloc+0x28/0x60 [ 5.773618] pinctrl_bind_pins+0x2b/0x2a0 [ 5.773618] really_probe+0x73/0x420 [ 5.773618] driver_probe_device+0x115/0x130 [ 5.773618] __driver_attach+0x103/0x110 [ 5.773618] ? driver_probe_device+0x130/0x130 [ 5.773618] bus_for_each_dev+0x67/0xc0 [ 5.773618] ? klist_add_tail+0x3b/0x70 [ 5.773618] bus_add_driver+0x41/0x260 [ 5.773618] ? pcie_port_setup+0x4d/0x4d [ 5.773618] driver_register+0x5b/0xe0 [ 5.773618] ? pcie_port_setup+0x4d/0x4d [ 5.773618] do_one_initcall+0x4e/0x1d4 [ 5.773618] ? init_setup+0x25/0x28 [ 5.773618] kernel_init_freeable+0x1c1/0x26e [ 5.773618] ? loglevel+0x5b/0x5b [ 5.773618] ? rest_init+0xb0/0xb0 [ 5.773618] kernel_init+0xa/0x110 [ 5.773618] ret_from_fork+0x22/0x40 [ 5.773618] Modules linked in: [ 5.773618] CR2: 0000000000002088 [ 5.773618] ---[ end trace 1030c9120a03d081 ]--- [...]
-4 other notes about the reproduction of this bug: On my test machine, this bug is covered by 'commit 0d76bcc960e6 ("Revert "ACPI/PCI: Pay attention to device-specific _PXM node values"")', but the crack caused by dev->numa_node is still exposed from other path.
II. history
I had a original try on [1], which took the way by deferring the instance of offline node.
Later Michal has suggested a fix [2], which only consider node with memory as online. Beside fixing this bug, that patch also aimed at excluding memory-less node as a candidate when iterating the zones. It is a pity that the method conflicts with the scheduler code, which assumes node with cpu as online too. You can find the broken by "git grep for_each_online_node | grep sched" or the discussion in tail of [3].
Since Michal has no time to continue on this issue. I pick it up again. This patch drops the change of "node online" definition in [2], i.e. still consider node as online if it has either cpu or memory. And keeps the rest main idea in [2] of initializing all parsed node on x86. For other archs, they need extra dedicated effort.
[1]: https://patchwork.kernel.org/patch/10738733/ [2]: https://lkml.org/lkml/2019/2/13/253 [3]: https://lore.kernel.org/lkml/20190528182011.GG1658@dhcp22.suse.cz/T/
Signed-off-by: Pingfan Liu <kernelfans@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pavel Tatashin <pavel.tatashin@microsoft.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Qian Cai <cai@lca.pw> Cc: Barret Rhoden <brho@google.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: David Rientjes <rientjes@google.com> Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- arch/x86/mm/numa.c | 17 ++++++++++++----- mm/page_alloc.c | 11 ++++++++--- 2 files changed, 20 insertions(+), 8 deletions(-)
diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c index b48d507..5f5b558 100644 --- a/arch/x86/mm/numa.c +++ b/arch/x86/mm/numa.c @@ -732,6 +732,15 @@ static void __init init_memory_less_node(int nid) */ } +static void __init init_parsed_rest_node(void) +{ + int node; + + for_each_node_mask(node, node_possible_map) + if (!node_online(node)) + init_memory_less_node(node); +} + /* * Setup early cpu_to_node. * @@ -752,6 +761,7 @@ void __init init_cpu_to_node(void) u16 *cpu_to_apicid = early_per_cpu_ptr(x86_cpu_to_apicid); BUG_ON(cpu_to_apicid == NULL); + init_parsed_rest_node(); for_each_possible_cpu(cpu) { int node = numa_cpu_node(cpu); @@ -759,11 +769,8 @@ void __init init_cpu_to_node(void) if (node == NUMA_NO_NODE) continue; - if (!node_online(node)) { - init_memory_less_node(node); - node_set_online(nid); - } - + if (!node_online(node)) + node_set_online(node); numa_set_node(cpu, node); } } diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d66bc8a..5d8db00 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5662,10 +5662,15 @@ static void __build_all_zonelists(void *data) if (self && !node_online(self->node_id)) { build_zonelists(self); } else { - for_each_online_node(nid) { + /* In rare case, node_zonelist() hits offline node */ + for_each_node(nid) { pg_data_t *pgdat = NODE_DATA(nid); - - build_zonelists(pgdat); + /* + * This condition can be removed on archs, with all + * possible node instanced. + */ + if (pgdat) + build_zonelists(pgdat); } #ifdef CONFIG_HAVE_MEMORYLESS_NODES -- 2.7.5
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