On Tue, Jul 30, 2013 at 10:29 PM, Stephen Warren <swarren at wwwdotorg.org> wrote: > On 07/30/2013 04:37 AM, Vijay Kilari wrote: >> On Fri, Jul 26, 2013 at 10:38 PM, Stephen Warren <swarren at wwwdotorg.org> wrote: > ... >>> Does a kernel that's used as the crash kernel guarantee: >>> >>> * Never to re-use the memory that was used by the previous kernel, so >>> that the spin loop code/data won't be corrupted, ever, no matter how >>> long the crash recovery kernel runs. >>> >>> * Not use SMP, so there's never a need to re-activate the non-boot CPUs, >>> which might not work if they aren't truly disabled but rather just >>> running a pin loop? >> >> From cat /proc/iomem, normal kernel is executed from (0x80xxxxxx) with crash >> kernel reserved 64M at 0xa0000000 >> >> 80000000-bfffffff : System RAM >> 80008000-805aeddf : Kernel code >> 805e2000-8063e427 : Kernel data >> a0000000-a3ffffff : Crash kernel >> >> crash kernel is loaded to reserved memory location and is executed from there. >> I could confirm this from /proc/iomem when crash kernel is running >> >> a0000000-a3efffff : System RAM >> a0008000-a05aeddf : Kernel code >> a05e2000-a063e427 : Kernel data > > OK, but in the crash dump kernel, is 80008000..8063e427 reserved as > well, which would guarantee that the spin loop being executed by the > non-crash CPUs won't be corrupted? The crash dump kernel runs from reserved memory area (0xa0000000 - 0xa3effffff). So it should not corrupt the memory area of original kernel that was running at 0x80000000,where other CPU's are in spin loop.
