Split single loop going over all pfn in mem_blk into 2 loops,
where outer loop goes over all sections and inner loop goes over
pfn from that section.
This is preparatory patch for next patch:
"skip non-present sections in register_mem_sect_under_node"
Signed-off-by: Jan Stancek <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
---
drivers/base/node.c | 41 ++++++++++++++++++++++++-----------------
1 file changed, 24 insertions(+), 17 deletions(-)
diff --git a/drivers/base/node.c b/drivers/base/node.c
index 31df474d72f4..4c7423a4b5f4 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -379,33 +379,40 @@ static int __init_refok get_nid_for_pfn(unsigned long pfn)
int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
{
int ret;
- unsigned long pfn, sect_start_pfn, sect_end_pfn;
+ unsigned long pfn, sect_start_pfn, sect_end_pfn, sect_no;
if (!mem_blk)
return -EFAULT;
if (!node_online(nid))
return 0;
- sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
- sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
- sect_end_pfn += PAGES_PER_SECTION - 1;
- for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
- int page_nid;
+ for (sect_no = mem_blk->start_section_nr;
+ sect_no <= mem_blk->end_section_nr;
+ sect_no++) {
- page_nid = get_nid_for_pfn(pfn);
- if (page_nid < 0)
- continue;
- if (page_nid != nid)
- continue;
- ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj,
- &mem_blk->dev.kobj,
- kobject_name(&mem_blk->dev.kobj));
- if (ret)
- return ret;
+ sect_start_pfn = section_nr_to_pfn(sect_no);
+ sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
+
+ for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
+ int page_nid;
- return sysfs_create_link_nowarn(&mem_blk->dev.kobj,
+ page_nid = get_nid_for_pfn(pfn);
+ if (page_nid < 0)
+ continue;
+ if (page_nid != nid)
+ continue;
+
+ ret = sysfs_create_link_nowarn(
+ &node_devices[nid]->dev.kobj,
+ &mem_blk->dev.kobj,
+ kobject_name(&mem_blk->dev.kobj));
+ if (ret)
+ return ret;
+
+ return sysfs_create_link_nowarn(&mem_blk->dev.kobj,
&node_devices[nid]->dev.kobj,
kobject_name(&node_devices[nid]->dev.kobj));
+ }
}
/* mem section does not span the specified node */
return 0;
--
1.8.3.1
Skip non-present sections in mem_blk to avoid crashing during boot
at register_mem_sect_under_node()->get_nid_for_pfn():
Unable to handle kernel paging request for data at address 0xf000000000080020
Faulting instruction address: 0xc00000000866b480
Oops: Kernel access of bad area, sig: 11 [#1]
SMP NR_CPUS=2048 NUMA pSeries
Modules linked in:
CPU: 14 PID: 1 Comm: swapper/14 Not tainted 4.2.0-rc8+ #6
task: c00000001e480000 ti: c00000001e500000 task.ti: c00000001e500000
NIP: c00000000866b480 LR: c00000000851aecc CTR: 0000000000000400
...
NIP [c00000000866b480] get_nid_for_pfn+0x10/0x30
LR [c00000000851aecc] register_mem_sect_under_node+0x9c/0x190
Call Trace:
[c00000001e503b10] [c0000000084f89a4] put_device+0x24/0x40 (unreliable)
[c00000001e503b60] [c00000000851b3d4] register_one_node+0x2b4/0x390
[c00000001e503bc0] [c000000008ae7a50] topology_init+0x4c/0x1e8
[c00000001e503c30] [c00000000800b3bc] do_one_initcall+0x10c/0x260
[c00000001e503d00] [c000000008ae41b4] kernel_init_freeable+0x27c/0x364
[c00000001e503dc0] [c00000000800bc14] kernel_init+0x24/0x130
[c00000001e503e30] [c000000008009530] ret_from_kernel_thread+0x5c/0xac
Instruction dump:
4e800020 60000000 60000000 60420000 3b80ffed 4bffffc8 00000000 00000000
3920ffff 78633664 792900c4 7d434a14 <e94a0020> 2faa0000 41de0010 7c63482a
---[ end trace e9ab4a173e0cee14 ]---
This has been observed during kdump kernel boot on ppc64le KVM guest
(page size: 65536, sections_per_block: 16, PAGES_PER_SECTION: 256)
where kdump adds "rtas" to list of usable regions:
# hexdump -C /sys/firmware/devicetree/base/rtas/linux,rtas-base
00000000 2f ff 00 00 |/...|
[ 0.000000] Early memory node ranges
[ 0.000000] node 0: [mem 0x0000000000000000-0x000000001fffffff]
[ 0.000000] node 0: [mem 0x000000002fff0000-0x000000002fffffff]
Crash happens when register_mem_sect_under_node goes over mem_blk that
spans sections 32-47, 32-46 are not present, 47 is present:
32 * 256 * 65536 == 0x20000000
47 * 256 * 65536 == 0x2f000000
It tries to access page for first pfn of this mem_blk (8192 == 32 * 256)
and crashes.
Signed-off-by: Jan Stancek <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
---
drivers/base/node.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/base/node.c b/drivers/base/node.c
index 4c7423a4b5f4..e638cfde7486 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -390,6 +390,9 @@ int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
sect_no <= mem_blk->end_section_nr;
sect_no++) {
+ if (!present_section_nr(sect_no))
+ continue;
+
sect_start_pfn = section_nr_to_pfn(sect_no);
sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
--
1.8.3.1