Hi Thadeu, Sorry for the late reply. "handle mem_section as either a pointer or an array" patch and "Always use bigger SECTION_MAP_MASK" patch modify the same line. I would like to reply about both patches by the end of the next week.
Thanks Tachibana > -----Original Message----- > From: kexec [mailto:kexec-boun...@lists.infradead.org] On Behalf Of Thadeu > Lima de Souza Cascardo > Sent: Friday, March 02, 2018 11:33 PM > To: kexec@lists.infradead.org > Subject: Re: [PATCH makedumpfile] handle mem_section as either a pointer or > an array > > Any comments or reviews on the patch below? > > Thanks. > Cascardo. > > On Mon, Feb 19, 2018 at 05:04:59PM -0300, Thadeu Lima de Souza Cascardo wrote: > > Some kernel versions that have been recently shipped have mem_section point > > to > > a pointer to the array, instead of pointing directly to the array. That only > > happens on SPARSEMEM_EXTREME configurations. > > > > As dwarf information might not be present that would have allowed us to > > detect > > which type it is, we need to try it either as an array or as the pointer to > > the > > array. Then, we validate all section_mem_map: they must either be present or > > null. If any problems are found when traversing it, consider it invalid. > > Only > > one way may be valid. Otherwise, fail. > > > > This has been tested with both types of kernels and succeeded in producing a > > compressed dump that could be analyzed with crash 7.2.1. > > > > Signed-off-by: Thadeu Lima de Souza Cascardo <casca...@canonical.com> > > --- > > makedumpfile.c | 153 > > +++++++++++++++++++++++++++++++++++++++++++-------------- > > makedumpfile.h | 1 + > > 2 files changed, 118 insertions(+), 36 deletions(-) > > > > diff --git a/makedumpfile.c b/makedumpfile.c > > index ed138d3..cd3fa4d 100644 > > --- a/makedumpfile.c > > +++ b/makedumpfile.c > > @@ -3297,7 +3297,7 @@ get_mm_discontigmem(void) > > return TRUE; > > } > > > > -unsigned long > > +static unsigned long > > nr_to_section(unsigned long nr, unsigned long *mem_sec) > > { > > unsigned long addr; > > @@ -3311,17 +3311,17 @@ nr_to_section(unsigned long nr, unsigned long > > *mem_sec) > > addr = SYMBOL(mem_section) + (nr * SIZE(mem_section)); > > } > > > > - if (!is_kvaddr(addr)) > > - return NOT_KV_ADDR; > > - > > return addr; > > } > > > > -unsigned long > > -section_mem_map_addr(unsigned long addr) > > +static unsigned long > > +section_mem_map_addr(unsigned long addr, unsigned long *map_mask) > > { > > char *mem_section; > > unsigned long map; > > + unsigned long mask; > > + > > + *map_mask = 0; > > > > if (!is_kvaddr(addr)) > > return NOT_KV_ADDR; > > @@ -3338,15 +3338,19 @@ section_mem_map_addr(unsigned long addr) > > } > > map = ULONG(mem_section + OFFSET(mem_section.section_mem_map)); > > if (info->kernel_version < KERNEL_VERSION(4, 13, 0)) > > - map &= SECTION_MAP_MASK_4_12; > > + mask = SECTION_MAP_MASK_4_12; > > else > > - map &= SECTION_MAP_MASK; > > + mask = SECTION_MAP_MASK; > > + *map_mask = map & ~mask; > > + if (map == 0x0) > > + *map_mask |= SECTION_MARKED_PRESENT; > > + map &= mask; > > free(mem_section); > > > > return map; > > } > > > > -unsigned long > > +static unsigned long > > sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long > > section_nr) > > { > > unsigned long mem_map; > > @@ -3354,17 +3358,110 @@ sparse_decode_mem_map(unsigned long coded_mem_map, > > unsigned long section_nr) > > mem_map = coded_mem_map + > > (SECTION_NR_TO_PFN(section_nr) * SIZE(page)); > > > > - if (!is_kvaddr(mem_map)) > > - return NOT_KV_ADDR; > > return mem_map; > > } > > + > > +/* > > + * On some kernels, mem_section may be a pointer or an array, when > > + * SPARSEMEM_EXTREME is on. > > + * > > + * We assume that section_mem_map is either 0 or has the present bit set. > > + * > > + */ > > + > > +static int > > +validate_mem_section(unsigned long *mem_sec, > > + unsigned long mem_section_ptr, unsigned int > > mem_section_size, > > + unsigned long *mem_maps, unsigned int num_section) > > +{ > > + unsigned int section_nr; > > + unsigned long map_mask; > > + unsigned long section, mem_map; > > + if (!readmem(VADDR, mem_section_ptr, mem_sec, mem_section_size)) { > > + ERRMSG("Can't read mem_section array.\n"); > > + return FALSE; > > + } > > + for (section_nr = 0; section_nr < num_section; section_nr++) { > > + section = nr_to_section(section_nr, mem_sec); > > + if (section == NOT_KV_ADDR) { > > + mem_map = NOT_MEMMAP_ADDR; > > + } else { > > + mem_map = section_mem_map_addr(section, &map_mask); > > + if (!(map_mask & SECTION_MARKED_PRESENT)) { > > + return FALSE; > > + } > > + if (mem_map == 0) { > > + mem_map = NOT_MEMMAP_ADDR; > > + } else { > > + mem_map = sparse_decode_mem_map(mem_map, > > + section_nr); > > + if (!is_kvaddr(mem_map)) { > > + return FALSE; > > + } > > + } > > + } > > + mem_maps[section_nr] = mem_map; > > + } > > + return TRUE; > > +} > > + > > +static int > > +get_mem_section(unsigned int mem_section_size, unsigned long *mem_maps, > > + unsigned int num_section) > > +{ > > + unsigned long mem_section_ptr; > > + int ret = FALSE; > > + unsigned long *mem_sec = NULL; > > + > > + if ((mem_sec = malloc(mem_section_size)) == NULL) { > > + ERRMSG("Can't allocate memory for the mem_section. %s\n", > > + strerror(errno)); > > + return FALSE; > > + } > > + ret = validate_mem_section(mem_sec, SYMBOL(mem_section), > > + mem_section_size, mem_maps, num_section); > > + > > + if (is_sparsemem_extreme()) { > > + int symbol_valid = ret; > > + int pointer_valid; > > + int mem_maps_size = sizeof(*mem_maps) * num_section; > > + unsigned long *mem_maps_ex = NULL; > > + if (!readmem(VADDR, SYMBOL(mem_section), &mem_section_ptr, > > + sizeof(mem_section_ptr))) > > + goto out; > > + > > + if ((mem_maps_ex = malloc(mem_maps_size)) == NULL) { > > + ERRMSG("Can't allocate memory for the mem_maps. %s\n", > > + strerror(errno)); > > + goto out; > > + } > > + > > + pointer_valid = validate_mem_section(mem_sec, > > + mem_section_ptr, > > + mem_section_size, > > + mem_maps_ex, > > + num_section); > > + if (pointer_valid) > > + memcpy(mem_maps, mem_maps_ex, mem_maps_size); > > + if (mem_maps_ex) > > + free(mem_maps_ex); > > + ret = symbol_valid ^ pointer_valid; > > + if (!ret) { > > + ERRMSG("Could not validate mem_section.\n"); > > + } > > + } > > +out: > > + if (mem_sec != NULL) > > + free(mem_sec); > > + return ret; > > +} > > + > > int > > get_mm_sparsemem(void) > > { > > unsigned int section_nr, mem_section_size, num_section; > > mdf_pfn_t pfn_start, pfn_end; > > - unsigned long section, mem_map; > > - unsigned long *mem_sec = NULL; > > + unsigned long *mem_maps = NULL; > > > > int ret = FALSE; > > > > @@ -3379,13 +3476,12 @@ get_mm_sparsemem(void) > > info->sections_per_root = _SECTIONS_PER_ROOT(); > > mem_section_size = SIZE(mem_section) * NR_SECTION_ROOTS(); > > } > > - if ((mem_sec = malloc(mem_section_size)) == NULL) { > > - ERRMSG("Can't allocate memory for the mem_section. %s\n", > > - strerror(errno)); > > + if ((mem_maps = malloc(sizeof(*mem_maps) * num_section)) == NULL) { > > + ERRMSG("Can't allocate memory for the mem_maps. %s\n", > > + strerror(errno)); > > return FALSE; > > } > > - if (!readmem(VADDR, SYMBOL(mem_section), mem_sec, > > - mem_section_size)) { > > + if (!get_mem_section(mem_section_size, mem_maps, num_section)) { > > ERRMSG("Can't get the address of mem_section.\n"); > > goto out; > > } > > @@ -3397,31 +3493,16 @@ get_mm_sparsemem(void) > > goto out; > > } > > for (section_nr = 0; section_nr < num_section; section_nr++) { > > - section = nr_to_section(section_nr, mem_sec); > > - if (section == NOT_KV_ADDR) { > > - mem_map = NOT_MEMMAP_ADDR; > > - } else { > > - mem_map = section_mem_map_addr(section); > > - if (mem_map == 0) { > > - mem_map = NOT_MEMMAP_ADDR; > > - } else { > > - mem_map = sparse_decode_mem_map(mem_map, > > - section_nr); > > - if (!is_kvaddr(mem_map)) > > - mem_map = NOT_MEMMAP_ADDR; > > - } > > - } > > pfn_start = section_nr * PAGES_PER_SECTION(); > > pfn_end = pfn_start + PAGES_PER_SECTION(); > > if (info->max_mapnr < pfn_end) > > pfn_end = info->max_mapnr; > > - dump_mem_map(pfn_start, pfn_end, mem_map, section_nr); > > + dump_mem_map(pfn_start, pfn_end, mem_maps[section_nr], > > section_nr); > > } > > ret = TRUE; > > out: > > - if (mem_sec != NULL) > > - free(mem_sec); > > - > > + if (mem_maps != NULL) > > + free(mem_maps); > > return ret; > > } > > > > diff --git a/makedumpfile.h b/makedumpfile.h > > index 01eece2..58e1aaa 100644 > > --- a/makedumpfile.h > > +++ b/makedumpfile.h > > @@ -184,6 +184,7 @@ isAnon(unsigned long mapping) > > #define SECTIONS_PER_ROOT() (info->sections_per_root) > > #define SECTION_ROOT_MASK() (SECTIONS_PER_ROOT() - 1) > > #define SECTION_NR_TO_ROOT(sec) ((sec) / SECTIONS_PER_ROOT()) > > +#define SECTION_MARKED_PRESENT (1UL<<0) > > #define SECTION_IS_ONLINE (1UL<<2) > > #define SECTION_MAP_LAST_BIT (1UL<<3) > > #define SECTION_MAP_MASK_4_12 (~(SECTION_IS_ONLINE-1)) > > -- > > 2.14.1 > > > > > > _______________________________________________ > > kexec mailing list > > kexec@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/kexec > > _______________________________________________ > kexec mailing list > kexec@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/kexec _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
