On Wed, Nov 20, 2013 at 05:29:16AM +0000, Atsushi Kumagai wrote: > On 2013/11/18 22:56:10, kexec <kexec-bounces at lists.infradead.org> wrote: > > On Mon, Nov 18, 2013 at 12:51:39AM +0000, Atsushi Kumagai wrote: > > > > [..] > > > > Is there any chance that you could look into fixing this. I have no > > > > experience writing code for makedumpfile. > > > > > > I'll send a patch to fix this soon. > > > > Thanks Atsushi. > > > > Vivek > > Vivek, could you test this patch ? > > Thanks > Atsushi Kumagai > > > From: Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp> > Date: Wed, 20 Nov 2013 10:05:03 +0900 > Subject: [PATCH] Disable mmap() for reading fractional pages. > > Since mmap() was introduced on /proc/vmcore, it fails > for fractional pages which don't start or end at page boundary > due to kernel issue. > This patch disables mmap() temporarily for fractional pages > to avoid this issue, so mmap() will be used only for aligned pages. > > Signed-off-by: Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp> Hi Atsushi, Even with this patch applied I see mmap() failure. mem_map (39) mem_map : ffffea0004e00000 pfn_start : 138000 pfn_end : 140000 read /proc/vmcore with mmap() Excluding unnecessary pages : [100.0 %] |STEP [Excluding unnecessary pages] : 0.035925 seconds Excluding unnecessary pages : [100.0 %] \STEP [Excluding unnecessary pages] : 0.035774 seconds Excluding unnecessary pages : [100.0 %] -STEP [Excluding unnecessary pages] : 0.035229 seconds Copying data : [ 40.9 %] -Can't map [b98fd000-b9cfd000] with mmap() read_from_vmcore: Can't read the dump memory(/proc/vmcore) with mmap(). readpage_elf: Can't read the dump memory(/proc/vmcore). readmem: type_addr: 1, addr:bffba000, size:4096 read_pfn: Can't get the page data. Resource temporarily unavailable makedumpfile Failed. kdump: saving vmcore failed Following is part of /proc/iomem on my system. 00100000-bffc283f : System RAM 01000000-018c551d : Kernel code 018c551e-01ef3f3f : Kernel data 0204a000-02984fff : Kernel bss 2e000000-35ffffff : Crash kernel bffc2840-bfffffff : reserved This is a different system than what I used last time. So I am not sure if this is same error or something else. But one thing is clear that System RAM last page is partial and we should face mmap() failure. Thanks Vivek
