[Crash-utility] [PATCH V2] Refactor kernel version checking code

In case linux banner can not be found in vmlinux for some reason. The fallback checking of "Linux version" failed for kernel 7.x with below error msg: WARNING: kernel version inconsistency between vmlinux and dumpfile crash: incompatible arguments: vmlinux is not SMP -- vmcore is SMP Jiri's case is OpenSUSE uses separate vmlinux.debug file, details see https://github.com/crash-utility/crash/issues/232 But update the kernel version number in kernel sanity checking code does workaround the issue. Let's fix this separately. A few improvements to the sanity checking including: - Replace hardcoded version checks (2.x through 6.x) with a unified kernel_version_str_sanity_check() function - Extend support to Linux 7.x kernels - Add proper bounds checking and null pointer validation - Ensure minor version number is numeric for stricter validation - Reduce code duplication in verify_namelist() and debug_kernel_version() Reported-by: Jiri Slaby <jirislaby(a)gmail.com&gt; Signed-off-by: Dave Young <yangrr.2009(a)tsinghua.org.cn&gt; --- [V1->V2]: refactore the code; address comments from Mukesh kernel.c | 39 +++++++++++++++++++++++++++++---------- 1 file changed, 29 insertions(+), 10 deletions(-) Index: crash/kernel.c =================================================================== --- crash.orig/kernel.c 2026-08-14 11:21:39.972971968 +0800 +++ crash/kernel.c 2026-08-14 11:21:42.371976057 +0800 @@ -29,6 +29,9 @@ #endif #include "bfd.h" +#define KERNEL_VERSION_MIN '2' +#define KERNEL_VERSION_MAX '7' /* latest linux mainline kernel major number */ + static void do_module_cmd(ulong, char *, ulong, char *, char *); static void show_module_taint(void); static char *find_module_objfile(char *, char *, char *); @@ -104,6 +107,30 @@ static int is_pvops_xen(void); static int get_linux_banner_from_vmlinux(char *, size_t); +static bool kernel_version_str_sanity_check(char *buf) +{ + int n; + char *p; + + if (!buf) + return FALSE; + + p = strstr(buf, "Linux version "); + if (!p) + return FALSE; + + n = strlen(p); + + if (n < 17) /* "Linux version " (14) + "x.y" (3) = 17 */ + return FALSE; + + if (p[14] >= KERNEL_VERSION_MIN && p[14] <= KERNEL_VERSION_MAX + && p[15] == '.' && p[16] >= '0' && p[16] <= '9') + return TRUE; + + return FALSE; +} + /* * popuplate the global kernel table (kt) with kernel version * information parsed from UTSNAME/OSRELEASE string @@ -1396,11 +1423,7 @@ found = FALSE; sprintf(buffer3, "(unknown)"); while (fgets(buffer, (BUFSIZE/2)-1, pipe)) { - if (!strstr(buffer, "Linux version 2.") && - !strstr(buffer, "Linux version 3.") && - !strstr(buffer, "Linux version 4.") && - !strstr(buffer, "Linux version 5.") && - !strstr(buffer, "Linux version 6.")) + if (!kernel_version_str_sanity_check(buffer)) continue; if (strstr(buffer, kt->proc_version)) { @@ -5987,11 +6010,7 @@ argc = 0; while (fgets(buf, BUFSIZE-1, pipe)) { - if (!strstr(buf, "Linux version 2.") && - !strstr(buf, "Linux version 3.") && - !strstr(buf, "Linux version 4.") && - !strstr(buf, "Linux version 5.") && - !strstr(buf, "Linux version 6.")) + if (!kernel_version_str_sanity_check(buf)) continue; argc = parse_line(buf, arglist);