On 09/19/23 at 09:42am, Andrew Morton wrote: > On Tue, 19 Sep 2023 12:02:17 +0800 kernel test robot <lkp@xxxxxxxxx> wrote: > > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > > head: 7fc7222d9680366edeecc219c21ca96310bdbc10 > > commit: 5c322f6aad10f0920f842a4ccf82e9b9f351c0a5 [5741/5912] crash_core.c: remove unneeded functions > > config: s390-buildonly-randconfig-r006-20220512 (https://download.01.org/0day-ci/archive/20230919/202309191144.B0MToaPG-lkp@xxxxxxxxx/config) > > compiler: s390-linux-gcc (GCC) 11.3.0 > > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230919/202309191144.B0MToaPG-lkp@xxxxxxxxx/reproduce) > > > > If you fix the issue in a separate patch/commit (i.e. not just a new version of > > the same patch/commit), kindly add following tags > > | Reported-by: kernel test robot <lkp@xxxxxxxxx> > > | Closes: https://lore.kernel.org/oe-kbuild-all/202309191144.B0MToaPG-lkp@xxxxxxxxx/ > > > > All warnings (new ones prefixed by >>): > > > > In file included from arch/s390/include/asm/atomic.h:12, > > from include/linux/atomic.h:7, > > from include/linux/mm_types_task.h:13, > > from include/linux/mm_types.h:5, > > from include/linux/buildid.h:5, > > from kernel/crash_core.c:7: > > kernel/crash_core.c: In function 'parse_crashkernel_suffix.constprop': > > >> kernel/crash_core.c:214:13: warning: argument 2 null where non-null expected [-Wnonnull] > > 214 | if (strncmp(cur, suffix, strlen(suffix))) { > > include/linux/compiler.h:68:10: note: in definition of macro '__trace_if_value' > > 68 | (cond) ? \ > > | ^~~~ > > include/linux/compiler.h:55:28: note: in expansion of macro '__trace_if_var' > > 55 | #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) ) > > | ^~~~~~~~~~~~~~ > > Looks legit? parse_crashkernel() does > > ret = __parse_crashkernel(cmdline, system_ram, crash_size, > crash_base, NULL); > > and that suffix==NULL gets passed through to the strncmp()? Yeah, this looks like a false positive report. I reproduced this, below change can mute the warning. However, the null pointer checking has been done in __parse_crashkernel() when calls parse_crashkernel_suffix(). Add below check anyway to satisfy the W=1 compiling? diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 1a77d466eaed..b53270ac3715 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -204,6 +204,9 @@ static int __init parse_crashkernel_suffix(char *cmdline, { char *cur = cmdline; + if(!suffix) + return -EINVAL; + *crash_size = memparse(cmdline, &cur); if (cmdline == cur) { pr_warn("crashkernel: memory value expected\n");
