Add stat object in diskdump_data. This is used in validation of entries of page descriptor table to avoid calling fstat() many times. The validation will be added in the next commit. --- diskdump.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/diskdump.c b/diskdump.c index 3ae7bf2..a495120 100644 --- a/diskdump.c +++ b/diskdump.c @@ -78,6 +78,7 @@ struct diskdump_data { int max_sect_len; /* highest bucket of valid_pages */ ulong accesses; ulong snapshot_task; + struct stat stat; }; static struct diskdump_data diskdump_data = { 0 }; @@ -967,6 +968,9 @@ restart: } } + if (fstat(dd->dfd, &dd->stat) < 0) + error(FATAL, "diskdump: cannot stat dumpfile\n"); + return TRUE; err: -- 2.43.1

Add function check_kdump_headers() that validates page descriptor table. This function is intended to be called when --validate_kdump_headers command-line option is specified. While the function name says checking kdump headers, current implementation checks only page descriptor table. This is to keep the implementation simple in the first discussion. The implementation can later be extended if necessary. Also the current implementation covers only a single dump file in the header version 6 or later. Split dump files and other header version are going to be covered in later versions of this patch set. --- diskdump.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) diff --git a/diskdump.c b/diskdump.c index 2d2cf97..5084b0d 100644 --- a/diskdump.c +++ b/diskdump.c @@ -93,6 +93,7 @@ static char *vmcoreinfo_read_string(const char *); static void diskdump_get_osrelease(void); static int valid_note_address(unsigned char *); static int sanity_check_page_desc(page_desc_t *); +static void check_kdump_headers(void); /* For split dumpfile */ static struct diskdump_data **dd_list = NULL; @@ -3145,3 +3146,39 @@ static int sanity_check_page_desc(page_desc_t *pd) (pd->size < dd->block_size && pd->flags & (DUMP_DH_COMPRESSED_ZLIB|DUMP_DH_COMPRESSED_LZO|DUMP_DH_COMPRESSED_SNAPPY|DUMP_DH_COMPRESSED_ZSTD))) && pd->page_flags == 0; } + +static void check_kdump_headers(void) +{ + ulong pfn, desc_pos; + off_t seek_offset; + page_desc_t pd; + int valid, ret; + + if (CRASHDEBUG(1)) + error(INFO, "pfn offset size flags page_flags\n"); + + for (pfn = 0; + pfn < dd->sub_header_kdump->max_mapnr_64; + pfn++) { + if (!page_is_dumpable(pfn)) + continue; + + desc_pos = pfn_to_pos(pfn); + seek_offset = dd->data_offset + + (off_t)(desc_pos - 1)*sizeof(page_desc_t); + ret = read_pd(dd->dfd, seek_offset, &pd); + if (ret) + return; + + if (!sanity_check_page_desc(&pd)) { + if (CRASHDEBUG(1)) + error(INFO, + "%lu %lu %u %08x %016lx\n", + pfn, + pd.offset, + pd.size, + pd.flags, + pd.page_flags); + } + } +} -- 2.43.1

Add --validate_kdump_headers command-line option. When this command-line option is specified, a whole part of page descriptor table is validated at the startup of crash utility. --- diskdump.c | 3 +++ main.c | 5 +++++ 2 files changed, 8 insertions(+) diff --git a/diskdump.c b/diskdump.c index 5084b0d..9a94e7e 100644 --- a/diskdump.c +++ b/diskdump.c @@ -1060,6 +1060,9 @@ is_diskdump(char *file) if (CRASHDEBUG(1)) __diskdump_memory_dump(fp); + if (pc->flags2 & VALIDATE_KDUMP_HEADERS) + check_kdump_headers(); + if (pc->flags2 & GET_OSRELEASE) diskdump_get_osrelease(); diff --git a/main.c b/main.c index 0b6b927..110d9c9 100644 --- a/main.c +++ b/main.c @@ -72,6 +72,7 @@ static struct option long_options[] = { {"hash", required_argument, 0, 0}, {"offline", required_argument, 0, 0}, {"src", required_argument, 0, 0}, + {"validate_kdump_headers", 0, 0, 0}, {0, 0, 0, 0} }; @@ -300,6 +301,10 @@ main(int argc, char **argv) else if (STREQ(long_options[option_index].name, "src")) kt->source_tree = optarg; + else if (STREQ(long_options[option_index].name, + "validate_kdump_headers")) + pc->flags2 |= VALIDATE_KDUMP_HEADERS; + else { error(INFO, "internal error: option %s unhandled\n", long_options[option_index].name); -- 2.43.1

Add description of --validate_kdump_headers command-line option. --- help.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/help.c b/help.c index a9c4d30..521588f 100644 --- a/help.c +++ b/help.c @@ -362,6 +362,10 @@ char *program_usage_info[] = { " Show or hide command output that is associated with offline cpus,", " overriding any settings in either ./.crashrc or $HOME/.crashrc.", "", + " --validate_kdump_headers", + " Validate kdump-compressed format during startup and show information" + " if invalid entries are found.", + "", "FILES:", "", " .crashrc", -- 2.43.1

Print elapsed time consumed in validation of page descriptor table. This is not intended to be merged, only for the purpose of discussion. --- diskdump.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/diskdump.c b/diskdump.c index db96fdb..eddf038 100644 --- a/diskdump.c +++ b/diskdump.c @@ -3162,6 +3162,9 @@ static void check_kdump_headers(void) off_t seek_offset; page_desc_t pd; int valid, ret; + struct timespec t1, t2; + + clock_gettime(CLOCK_REALTIME, &t1); if (CRASHDEBUG(1)) error(INFO, "pfn offset size flags page_flags\n"); @@ -3190,4 +3193,12 @@ static void check_kdump_headers(void) pd.page_flags); } } + + clock_gettime(CLOCK_REALTIME, &t2); + + if (CRASHDEBUG(1)) { + error(INFO, + "XXXXX %lu seconds consumed for verification of headers\n", + t2.tv_sec - t1.tv_sec); + } } -- 2.43.1