Re: [bugfix] mm: zone_end_pfn is too small

[Ingo Molnar <mingo@kernel.org>]

* Russ Anderson <rja@sgi.com> wrote:

> Booting with 32 TBytes memory hits BUG at mm/page_alloc.c:552! (output below).
> 
> The key hint is "page 4294967296 outside zone".
> 4294967296 = 0x100000000 (bit 32 is set).
> 
> The problem is in include/linux/mmzone.h:
> 
> 530 static inline unsigned zone_end_pfn(const struct zone *zone)
> 531 {
> 532         return zone->zone_start_pfn + zone->spanned_pages;
> 533 }
> 
> zone_end_pfn is "unsigned" (32 bits).  Changing it to 
> "unsigned long" (64 bits) fixes the problem.
> 
> zone_end_pfn() was added recently in commit 108bcc96ef7047c02cad4d229f04da38186a3f3f.
> http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/include/linux/mmzone.h?id=108bcc96ef7047c02cad4d229f04da38186a3f3f
> 
> 
> Output from the failure.
> 
>   No AGP bridge found
>   page 4294967296 outside zone [ 4294967296 - 4327469056 ]
>   ------------[ cut here ]------------
>   kernel BUG at mm/page_alloc.c:552!
>   invalid opcode: 0000 [#1] SMP 
>   Modules linked in:
>   CPU 0 
>   Pid: 0, comm: swapper Not tainted 3.9.0-rc2.dtp+ #10  
>   RIP: 0010:[<ffffffff811477d2>]  [<ffffffff811477d2>] free_one_page+0x382/0x430
>   RSP: 0000:ffffffff81943d98  EFLAGS: 00010002
>   RAX: 0000000000000001 RBX: ffffea4000000000 RCX: 000000000000b3d9
>   RDX: 0000000000000000 RSI: 0000000000000086 RDI: 0000000000000046
>   RBP: ffffffff81943df8 R08: 0000000000000040 R09: 0000000000000023
>   R10: 00000000000034bf R11: 00000000000034bf R12: ffffea4000000000
>   R13: ffff981efefd9d80 R14: 0000000000000006 R15: 0000000000000006
>   FS:  0000000000000000(0000) GS:ffffc90000000000(0000) knlGS:0000000000000000
>   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>   CR2: ffffc7defefff000 CR3: 000000000194e000 CR4: 00000000000406b0
>   DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>   DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
>   Process swapper (pid: 0, threadinfo ffffffff81942000, task ffffffff81955420)
>   Stack:
>    00000000000000ff ffffc900000100a0 ffffc900000100d0 ffffffff00000040
>    0000000000000000 0000000081148809 0000000000000097 ffffea4000000000
>    0000000000000006 0000000000000002 0000000101e82bc0 ffffea4000001000
>   Call Trace:
>    [<ffffffff81149176>] __free_pages_ok+0x96/0xb0
>    [<ffffffff8114c585>] __free_pages+0x25/0x50
>    [<ffffffff8164c006>] __free_pages_bootmem+0x8a/0x8c
>    [<ffffffff81a9684f>] __free_memory_core+0xea/0x131
>    [<ffffffff81a968e0>] free_low_memory_core_early+0x4a/0x98
>    [<ffffffff81a96973>] free_all_bootmem+0x45/0x47
>    [<ffffffff81a87cff>] mem_init+0x7b/0x14c
>    [<ffffffff81a70051>] start_kernel+0x216/0x433
>    [<ffffffff81a6fc59>] ? repair_env_string+0x5b/0x5b
>    [<ffffffff81a6f5f7>] x86_64_start_reservations+0x2a/0x2c
>    [<ffffffff81a6f73d>] x86_64_start_kernel+0x144/0x153
>   Code: 89 f1 ba 01 00 00 00 31 f6 d3 e2 4c 89 ef e8 66 a4 01 00 e9 2c fe ff ff 0f 0b eb fe 0f 0b 66 66 2e 0f 1f 84 00 00 00 00 00 eb f3 <0f> 0b eb fe 0f 0b 0f 1f 84 00 00 00 00 00 eb f6 0f 0b eb fe 49 
>   RIP  [<ffffffff811477d2>] free_one_page+0x382/0x430
>    RSP <ffffffff81943d98>
>   ---[ end trace a7919e7f17c0a725 ]---
>   Kernel panic - not syncing: Attempted to kill the idle task!
> 
> Signed-off-by: Russ Anderson <rja@sgi.com>
> Reported-by: George Beshers <gbeshers@sgi.com>
> Acked-by: Hedi Berriche <hedi@sgi.com>
> 
> ---
>  include/linux/mmzone.h |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> Index: linux/include/linux/mmzone.h
> ===================================================================
> --- linux.orig/include/linux/mmzone.h	2013-03-18 10:06:59.744082190 -0500
> +++ linux/include/linux/mmzone.h	2013-03-18 10:23:27.374031648 -0500
> @@ -527,7 +527,7 @@ static inline int zone_is_oom_locked(con
>  	return test_bit(ZONE_OOM_LOCKED, &zone->flags);
>  }
>  
> -static inline unsigned zone_end_pfn(const struct zone *zone)
> +static inline unsigned long zone_end_pfn(const struct zone *zone)
>  {
>  	return zone->zone_start_pfn + zone->spanned_pages;
>  }

Ouch...

Any way to get the compiler to complain about the harmful integer 
truncation here that happens on 64-bit platforms?

Thanks,

	Ingo

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