I had a bug report because of a truncated vmcore file. The error message just was crash: read error: kernel virtual address: ffff8107f3c3a6c0 type: "cpu_pda entry" which is very unclear for a 'normal' user. This patch adds checking of the file size according to the ELF header at the beginning so that a clear error message can be printed. Please consider adding the patch to crash. Signed-off-by: Bernhard Walle <bwalle(a)suse.de&gt; --- defs.h | 1 + netdump.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 45 insertions(+) --- a/defs.h +++ b/defs.h @@ -16,6 +16,7 @@ * GNU General Public License for more details. */ +#define _LARGEFILE64_SOURCE 1 /* stat64() */ #ifndef GDB_COMMON #include <stdio.h> --- a/netdump.c +++ b/netdump.c @@ -33,6 +33,47 @@ static physaddr_t xen_kdump_p2m(physaddr #define ELFREAD 0 #define MIN_PAGE_SIZE (4096) + + +static int +check_netdump_filesize(char *file) +{ + uint64_t max_file_offset = 0; + struct pt_load_segment *pls; + struct stat64 stat; + int i, ret; + + + /* find the maximum file offset */ + for (i = 0; i < nd->num_pt_load_segments; i++) { + uint64_t end, size; + + pls = &nd->pt_load_segments[i]; + + size = pls->phys_end - pls->phys_start; + end = pls->file_offset + size; + + if (end > max_file_offset) + max_file_offset = end; + } + + ret = stat64(file, &stat); + if (ret < 0) { + fprintf(stderr, "Cannot stat64 on %s: %s\n", file, + strerror(errno)); + return FALSE; + } + + if (max_file_offset > stat.st_size) { + fprintf(stderr, "File %s is too short:\n" + "Must be %lld bytes but is only " + "%lld bytes long.\n", + file, max_file_offset, stat.st_size); + return FALSE; + } + + return TRUE; +} /* * Determine whether a file is a netdump/diskdump/kdump creation, @@ -267,6 +308,9 @@ is_netdump(char *file, ulong source_quer if (CRASHDEBUG(1)) netdump_memory_dump(fp); + if (!check_netdump_filesize(file)) + return FALSE; + return nd->header_size; bailout: