Hey All,
With 2.6.21 and the current -git, we're seeing the following oops when
we try sysrq-m:
...
Node 1 Normal: 85*4kB 34*8kB 20*16kB 4*32kB 3*64kB 0*128kB 1*256kB
0*512kB 1*1024kB 0*2048kB 953*4096kB =
3906020kB
Swap cache: add 0, delete 0, find 0/0, race 0+0
Free swap = 2040212kB
Total swap = 2040212kB
Unable to handle kernel paging request at 0000000003480000 RIP:
[<ffffffff8102a16d>] show_mem+0xdd/0x1e0
PGD 2052e9067 PUD 2052ea067 PMD 0
Oops: 0000 [1] PREEMPT SMP
CPU 3
Pid: 0, comm: swapper Not tainted 2.6.22-rc3-git7john #6
RIP: 0010:[<ffffffff8102a16d>] [<ffffffff8102a16d>] show_mem+0xdd/0x1e0
RSP: 0018:ffff810211f8bdf8 EFLAGS: 00010006
RAX: 0000000000780000 RBX: 00000000000f0000 RCX: 0000000003480000
RDX: 0000000003480000 RSI: ffff81000210a0f0 RDI: 0000000000112000
RBP: 00000000000f0000 R08: 00000000ffffffff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff810000012189
R13: 0000000000007179 R14: 0000000000000000 R15: 0000000000000000
FS: 00002ba3b8bdbf40(0000) GS:ffff810211f629c0(0000)
knlGS:0000000000000000
CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: 0000000003480000 CR3: 00000002052e8000 CR4: 00000000000006e0
Process swapper (pid: 0, threadinfo ffff8101118be000, task
ffff810211f70080)
Stack: 0000000000000000 ffffffff81a90460 0000000000000001
000000000000006d
ffff810110bf6000 0000000000000006 0000000000000002 ffffffff812e0046
ffff81011584fbc0 ffffffff820cc590 0000000000000061 000000000000006d
Call Trace:
<IRQ> [<ffffffff812e0046>] __handle_sysrq+0x86/0x140
[<ffffffff8134309c>] receive_chars+0x27c/0x300
[<ffffffff8105a600>] hrtimer_wakeup+0x0/0x30
[<ffffffff8105c857>] clocksource_get_next+0x47/0x60
[<ffffffff813444d2>] serial8250_interrupt+0x142/0x160
[<ffffffff81076c94>] handle_IRQ_event+0x34/0x70
[<ffffffff8107838a>] handle_edge_irq+0xca/0x150
[<ffffffff8100d6cd>] do_IRQ+0xbd/0x1b0
[<ffffffff81008ef0>] default_idle+0x0/0x40
[<ffffffff8100a971>] ret_from_intr+0x0/0xa
<EOI> [<ffffffff816ab340>] unix_poll+0x0/0xb0
[<ffffffff81008f19>] default_idle+0x29/0x40
[<ffffffff81008f9f>] cpu_idle+0x6f/0xe0
Code: 8b 02 f6 c4 04 75 92 8b 02 66 85 c0 79 7a 48 83 c5 01 49 83
RIP [<ffffffff8102a16d>] show_mem+0xdd/0x1e0
RSP <ffff810211f8bdf8>
CR2: 0000000003480000
Kernel panic - not syncing: Aiee, killing interrupt handler!
I'll keep digging but I wanted to see if anyone had any quick thoughts
or suggestions.
thanks
-john
On 06/06/2007 08:27 PM, john stultz wrote:
> Hey All,
> With 2.6.21 and the current -git, we're seeing the following oops when
> we try sysrq-m:
>
It's here in arch/x86_64/mm/init.c::show_mem():
for_each_online_pgdat(pgdat) {
for (i = 0; i < pgdat->node_spanned_pages; ++i) {
page = pfn_to_page(pgdat->node_start_pfn + i);
total++;
======> if (PageReserved(page))
reserved++;
else if (PageSwapCache(page))
cached++;
else if (page_count(page))
shared += page_count(page) - 1;
}
}
page is completely bogus (it's 0x0000000003480000)
Chuck Ebbert wrote: [Thu Jun 07 2007, 11:42:38AM EDT]
> On 06/06/2007 08:27 PM, john stultz wrote:
> > Hey All,
> > With 2.6.21 and the current -git, we're seeing the following oops when
> > we try sysrq-m:
> >
>
> It's here in arch/x86_64/mm/init.c::show_mem():
>
> for_each_online_pgdat(pgdat) {
> for (i = 0; i < pgdat->node_spanned_pages; ++i) {
This is probably with sparsemem? I'm working with [email protected] to
test a patch. Basically you need to validate the pfn because it
could be in a hole. Most arches which support sparsemem perform this
check.
if (!pfn_valid(pgdat->node_start_pfn + i))
continue;
bob
> page = pfn_to_page(pgdat->node_start_pfn + i);
> total++;
> ======> if (PageReserved(page))
> reserved++;
> else if (PageSwapCache(page))
> cached++;
> else if (page_count(page))
> shared += page_count(page) - 1;
> }
> }
>
> page is completely bogus (it's 0x0000000003480000)
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
On Thu, 2007-06-07 at 14:21 -0400, Bob Picco wrote:
> Chuck Ebbert wrote: [Thu Jun 07 2007, 11:42:38AM EDT]
> > On 06/06/2007 08:27 PM, john stultz wrote:
> > > Hey All,
> > > With 2.6.21 and the current -git, we're seeing the following oops when
> > > we try sysrq-m:
> > >
> >
> > It's here in arch/x86_64/mm/init.c::show_mem():
> >
> > for_each_online_pgdat(pgdat) {
> > for (i = 0; i < pgdat->node_spanned_pages; ++i) {
> This is probably with sparsemem? I'm working with [email protected] to
> test a patch. Basically you need to validate the pfn because it
> could be in a hole. Most arches which support sparsemem perform this
> check.
>
> if (!pfn_valid(pgdat->node_start_pfn + i))
> continue;
Yep. That catch avoids the issue! Sounds like a 2.6.21.x candidate.
thanks so much!
-john
Bob Picco wrote:
> Chuck Ebbert wrote: [Thu Jun 07 2007, 11:42:38AM EDT]
>> On 06/06/2007 08:27 PM, john stultz wrote:
>>> Hey All,
>>> With 2.6.21 and the current -git, we're seeing the following oops when
>>> we try sysrq-m:
>>>
>> It's here in arch/x86_64/mm/init.c::show_mem():
>>
>> for_each_online_pgdat(pgdat) {
>> for (i = 0; i < pgdat->node_spanned_pages; ++i) {
> This is probably with sparsemem? I'm working with [email protected] to
> test a patch. Basically you need to validate the pfn because it
> could be in a hole. Most arches which support sparsemem perform this
> check.
>
> if (!pfn_valid(pgdat->node_start_pfn + i))
> continue;
> bob
Yep you would want one of those for sure with sparsemem.
-apw
>> page = pfn_to_page(pgdat->node_start_pfn + i);
>> total++;
>> ======> if (PageReserved(page))
>> reserved++;
>> else if (PageSwapCache(page))
>> cached++;
>> else if (page_count(page))
>> shared += page_count(page) - 1;
>> }
>> }
>>
>> page is completely bogus (it's 0x0000000003480000)
>> -
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>> the body of a message to [email protected]
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at http://www.tux.org/lkml/
john stultz wrote: [Thu Jun 07 2007, 03:54:41PM EDT]
[snip]
john you are welcome.
We aren't sampling for holes in memory. Thus we encounter a section hole with
empty section map pointer for SPARSEMEM and OOPs for show_mem. This issue
has been seen in 2.6.21, current git and current mm. The patch below
is for mainline and mm. It was boot tested for SPARSEMEM, current
VMEMMAP of Andy's in mm ml and DISCONTIGMEM. A slightly different patch
will be posted to stable for 2.6.21.
Previous to commit f0a5a58aa812b31fd9f197c4ba48245942364eae memory_present
was called for node_start_pfn to node_end_pfn. This would cover the hole(s)
with reserved pages and valid sections. Most SPARSEMEM supported arches
do a pfn_valid check in show_mem before computing the page structure address.
This issue was brought to my attention on IRC by Arnaldo Carvalho de Melo at
[email protected]. Thanks to Arnaldo for testing.
Signed-off-by: Bob Picco <[email protected]>
arch/x86_64/mm/init.c | 2 ++
1 file changed, 2 insertions(+)
Index: linux-2.6.22-rc4-mm1/arch/x86_64/mm/init.c
===================================================================
--- linux-2.6.22-rc4-mm1.orig/arch/x86_64/mm/init.c 2007-06-06 12:59:26.000000000 -0400
+++ linux-2.6.22-rc4-mm1/arch/x86_64/mm/init.c 2007-06-07 11:14:31.000000000 -0400
@@ -79,6 +79,8 @@ void show_mem(void)
if (unlikely(i % MAX_ORDER_NR_PAGES == 0)) {
touch_nmi_watchdog();
}
+ if (!pfn_valid(pgdat->node_start_pfn + i))
+ continue;
page = pfn_to_page(pgdat->node_start_pfn + i);
total++;
if (PageReserved(page))
Bob Picco wrote:
> john stultz wrote: [Thu Jun 07 2007, 03:54:41PM EDT]
> [snip]
> john you are welcome.
>
> We aren't sampling for holes in memory. Thus we encounter a section hole with
> empty section map pointer for SPARSEMEM and OOPs for show_mem. This issue
> has been seen in 2.6.21, current git and current mm. The patch below
> is for mainline and mm. It was boot tested for SPARSEMEM, current
> VMEMMAP of Andy's in mm ml and DISCONTIGMEM. A slightly different patch
> will be posted to stable for 2.6.21.
>
> Previous to commit f0a5a58aa812b31fd9f197c4ba48245942364eae memory_present
> was called for node_start_pfn to node_end_pfn. This would cover the hole(s)
> with reserved pages and valid sections. Most SPARSEMEM supported arches
> do a pfn_valid check in show_mem before computing the page structure address.
>
> This issue was brought to my attention on IRC by Arnaldo Carvalho de Melo at
> [email protected]. Thanks to Arnaldo for testing.
>
> Signed-off-by: Bob Picco <[email protected]>
>
> arch/x86_64/mm/init.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> Index: linux-2.6.22-rc4-mm1/arch/x86_64/mm/init.c
> ===================================================================
> --- linux-2.6.22-rc4-mm1.orig/arch/x86_64/mm/init.c 2007-06-06 12:59:26.000000000 -0400
> +++ linux-2.6.22-rc4-mm1/arch/x86_64/mm/init.c 2007-06-07 11:14:31.000000000 -0400
> @@ -79,6 +79,8 @@ void show_mem(void)
> if (unlikely(i % MAX_ORDER_NR_PAGES == 0)) {
> touch_nmi_watchdog();
> }
> + if (!pfn_valid(pgdat->node_start_pfn + i))
> + continue;
> page = pfn_to_page(pgdat->node_start_pfn + i);
> total++;
> if (PageReserved(page))
Yes this is required with SPARSEMEM. Good spot.
Acked-by: Andy Whitcroft <[email protected]>
-apw