Description of problem: kdump initialization always fails on x86_64 Version-Release number of selected component: 2.6.18-15.el5 or later How reproducible: Always on x86_64 Steps to Reproduce: 0. setup kdump 1. pass "crashkernel=128M@16M" boot parameter to kernel 2. do "service kdump start" 3. grep "Crash" /proc/iomem Actual results: The step 2 fails. The step 3 shows "00000000-00000000 : Crash kernel". dmesg shows "Memory for crash kernel (0x1000000 to 0x8ffffff) notwithin permissible range" "disabling kdump". Expected results: The step 2 succeeds. The step 3 shows "01000000-08ffffff : Crash kernel". Hardware info: Additional Info: This is a regression introduced since 2.6.18-15.el5. The following patch is a suspect. linux-2.6-kdump-bounds-checking-for-crashkernel-args.patch The patch adds a code to check the boundary based on max_low_pfn. The code for x86_64 is implemented in setup_arch(), which is called earlier than mem_init(), which sets max_low_pfn. So the check always fails.
Created attachment 156293 [details] use end_pfn instead of uninitialized max_low_pfn max_low_pfn is not yet initialized in setup_arch(). Using end_pfn would solve the issue. Tested on x86_64.
*** This bug has been marked as a duplicate of 242648 ***