Hello, hopefully this is the correct mailing list for this question:

I'm working on a derivative of the mainline Linux 3.8 kernel and I'm trying to enable ARM kdump functionality to collect crashdumps when we have kernel problems. But, there's some kind of unresolved issue in arch/arm/mm/ioremap.c which prevents /proc/vmcore from being able to function properly. I checked and this appears to still be in kernel.org Linux 3.13. The target is a normal, recent ARMv7 chip.

Has this issue been addressed in any version of Linaro's kernel? Or, is there a work-around? If not, how does a crashdump file get generated when/if the Linaro kernel crashes or a driver faults?

>> WARNING: at arch/arm/mm/ioremap.c:244 __arm_ioremap_pfn_caller+0x1d8/0x1f0()

>> Modules linked in:

>> [<c0016660>] (unwind_backtrace+0x0/0x138) from [<c0020480>] (warn_slowpath_common+0x4c/0x64)

>> [<c0020480>] (warn_slowpath_common+0x4c/0x64) from [<c00204b4>] (warn_slowpath_null+0x1c/0x24)

>> [<c00204b4>] (warn_slowpath_null+0x1c/0x24) from [<c0018e9c>] (__arm_ioremap_pfn_caller+0x1d8/0x1f0)

>> [<c0018e9c>] (__arm_ioremap_pfn_caller+0x1d8/0x1f0) from [<c0018f20>] (__arm_ioremap_caller+0x54/0x5c)

>> [<c0018f20>] (__arm_ioremap_caller+0x54/0x5c) from [<c0018c58>] (__arm_ioremap+0x18/0x1c)

>> [<c0018c58>] (__arm_ioremap+0x18/0x1c) from [<c00168fc>] (copy_oldmem_page+0x34/0xc0)

>> [<c00168fc>] (copy_oldmem_page+0x34/0xc0) from [<c010350c>] (read_from_oldmem+0xb8/0xe4)

>> [<c010350c>] (read_from_oldmem+0xb8/0xe4) from [<c05c37e0>] (parse_crash_elf32_headers+0x184/0x43c)

>> [<c05c37e0>] (parse_crash_elf32_headers+0x184/0x43c) from [<c05c3b64>] (vmcore_init+0xcc/0x198)

>> [<c05c3b64>] (vmcore_init+0xcc/0x198) from [<c000863c>] (do_one_initcall+0x34/0x184)

>> [<c000863c>] (do_one_initcall+0x34/0x184) from [<c05b28dc>] (kernel_init_freeable+0xfc/0x1c8)

>> [<c05b28dc>] (kernel_init_freeable+0xfc/0x1c8) from [<c04326d4>] (kernel_init+0x8/0xe4)

>> [<c04326d4>] (kernel_init+0x8/0xe4) from [<c000ec58>] (ret_from_fork+0x14/0x3c)

>>

>> arch/arm/mm/ioremap.c:244

>>        /*

>>          * Don't allow RAM to be mapped - this causes problems with ARMv6+

>>          */

>>         if (WARN_ON(pfn_valid(pfn)))

>>                 return NULL;

Thanks in advance for any help.

-andy