From: Philipp Rudo <prudo@xxxxxxxxxx> Subject: kernel/crash_core: suppress unknown crashkernel parameter warning When booting with crashkernel= on the kernel command line a warning similar to [ 0.038294] Kernel command line: ro console=ttyS0 crashkernel=256M [ 0.038353] Unknown kernel command line parameters "crashkernel=256M", will be passed to user space. is printed. This comes from crashkernel= being parsed independent from the kernel parameter handling mechanism. So the code in init/main.c doesn't know that crashkernel= is a valid kernel parameter and prints this incorrect warning. Suppress the warning by adding a dummy early_param handler for crashkernel=. Link: https://lkml.kernel.org/r/20211208133443.6867-1-prudo@xxxxxxxxxx Fixes: 86d1919a4fb0 ("init: print out unknown kernel parameters") Signed-off-by: Philipp Rudo <prudo@xxxxxxxxxx> Acked-by: Baoquan He <bhe@xxxxxxxxxx> Cc: Andrew Halaney <ahalaney@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/crash_core.c | 11 +++++++++++ 1 file changed, 11 insertions(+) --- a/kernel/crash_core.c~kernel-crash_core-suppress-unknown-crashkernel-parameter-warning +++ a/kernel/crash_core.c @@ -6,6 +6,7 @@ #include <linux/buildid.h> #include <linux/crash_core.h> +#include <linux/init.h> #include <linux/utsname.h> #include <linux/vmalloc.h> @@ -295,6 +296,16 @@ int __init parse_crashkernel_low(char *c "crashkernel=", suffix_tbl[SUFFIX_LOW]); } +/* + * Add a dummy early_param handler to mark crashkernel= as a known command line + * parameter and suppress incorrect warnings in init/main.c. + */ +static int __init parse_crashkernel_dummy(char *arg) +{ + return 0; +} +early_param("crashkernel", parse_crashkernel_dummy); + Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type, void *data, size_t data_len) { _
