Re: [Crash-utility] [makedumpfile][patch] handle !SPARSEMEM_EX properly

In !SPARSEMEM_EX case, the symbol mem_section points a array of struct mem_section, doesn't point a array of pointer to mem_section[], so I think the check: if (!is_kvaddr(mem_sec[SECTION_NR_TO_ROOT(nr)])) return NOT_KV_ADDR; in nr_to_section() is not a valid check in this case. To make the matters worse, if CONFIG_CGROUP_MEM_RES_CTLR is enabled, the end of struct mem_section is padded with 0. So, reading mem_section by "rd" of crash will look like: crash> rd mem_section 128 c08b71e0: c9002003 c9001200 f7000000 00000000 . .............. c08b71f0: c9002003 c9001260 f6980000 00000000 . ..`........... c08b7200: c9002003 c90012c0 f6300000 00000000 . ........0..... c08b7210: c9002003 c9001320 f5c80000 00000000 . .. ........... ...

This means nr_to_section() will return 0 when "nr" is 3,7,11,... because it meets the condition(mem_sec[SECTION_NR_TO_ROOT(nr)] == mem_sec[nr] == 0 == !is_kvaddr). As a result, mem_map for section 3,7,11,... cannot be handled properly. This patch is a fix for this problem. nr_to_section() will check "addr" by is_kvaddr() later anyway, so this patch just removes the problematic check. Signed-off-by: Masayuki Igawa <igawa(a)mxs.nes.nec.co.jp&gt; Signed-off-by: Daisuke Nishimura <nishimura(a)mxp.nes.nec.co.jp&gt; --- diff --git a/makedumpfile.c b/makedumpfile.c index 855c718..73fa94f 100644 --- a/makedumpfile.c +++ b/makedumpfile.c @@ -3547,9 +3547,6 @@ nr_to_section(unsigned long nr, unsigned long *mem_sec) { unsigned long addr; - if (!is_kvaddr(mem_sec[SECTION_NR_TO_ROOT(nr)])) - return NOT_KV_ADDR; - if (is_sparsemem_extreme()) addr = mem_sec[SECTION_NR_TO_ROOT(nr)] + (nr & SECTION_ROOT_MASK()) * SIZE(mem_section);