* [trace:bootconfig/for-next 16/16] init/main.c:437:20: warning: stack frame size (4192) exceeds limit (2048) in 'bootconfig_apply_early_params'
@ 2026-03-25 2:37 kernel test robot
2026-03-25 6:52 ` Masami Hiramatsu
0 siblings, 1 reply; 3+ messages in thread
From: kernel test robot @ 2026-03-25 2:37 UTC (permalink / raw)
To: Breno Leitao; +Cc: llvm, oe-kbuild-all, Masami Hiramatsu (Google)
tree: https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace bootconfig/for-next
head: 1a427f2a710583872b6176ea8378e0a1a8719fc4
commit: 1a427f2a710583872b6176ea8378e0a1a8719fc4 [16/16] bootconfig: Apply early options from embedded config
config: loongarch-allmodconfig (https://download.01.org/0day-ci/archive/20260325/202603251010.5Ui0yrB2-lkp@intel.com/config)
compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260325/202603251010.5Ui0yrB2-lkp@intel.com/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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603251010.5Ui0yrB2-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> init/main.c:437:20: warning: stack frame size (4192) exceeds limit (2048) in 'bootconfig_apply_early_params' [-Wframe-larger-than]
437 | static void __init bootconfig_apply_early_params(void)
| ^
1 warning generated.
vim +/bootconfig_apply_early_params +437 init/main.c
416
417 /*
418 * do_early_param() is defined later in this file but called from
419 * bootconfig_apply_early_params() below, so we need a forward declaration.
420 */
421 static int __init do_early_param(char *param, char *val,
422 const char *unused, void *arg);
423
424 /*
425 * bootconfig_apply_early_params - dispatch kernel.* keys from the embedded
426 * bootconfig as early_param() calls.
427 *
428 * early_param() handlers must run before most of the kernel initialises
429 * (e.g. before the GIC driver reads irqchip.gicv3_pseudo_nmi). A bootconfig
430 * attached to the initrd arrives too late for this because the initrd is not
431 * mapped yet when early params are processed. The embedded bootconfig lives
432 * in the kernel image itself (.init.data), so it is always reachable.
433 *
434 * This function is called from setup_boot_config() which runs in
435 * start_kernel() before parse_early_param(), making the timing correct.
436 */
> 437 static void __init bootconfig_apply_early_params(void)
438 {
439 char val_buf[COMMAND_LINE_SIZE];
440 struct xbc_node *knode, *root;
441 const char *val;
442
443 root = xbc_find_node("kernel");
444 if (!root)
445 return;
446
447 /*
448 * Keys that do not match any early_param() handler are silently
449 * ignored — do_early_param() always returns 0.
450 */
451 xbc_node_for_each_key_value(root, knode, val) {
452 if (xbc_node_compose_key_after(root, knode, xbc_namebuf, XBC_KEYLEN_MAX) < 0)
453 continue;
454
455 if (!val) {
456 do_early_param(xbc_namebuf, NULL, NULL, NULL);
457 continue;
458 }
459
460 /*
461 * We need to copy const char *val to a char pointer,
462 * which is what do_early_param() need, given it might
463 * call strsep(), strtok() later.
464 */
465 strscpy(val_buf, val, sizeof(val_buf));
466 do_early_param(xbc_namebuf, val_buf, NULL, NULL);
467 }
468 }
469
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [trace:bootconfig/for-next 16/16] init/main.c:437:20: warning: stack frame size (4192) exceeds limit (2048) in 'bootconfig_apply_early_params'
2026-03-25 2:37 [trace:bootconfig/for-next 16/16] init/main.c:437:20: warning: stack frame size (4192) exceeds limit (2048) in 'bootconfig_apply_early_params' kernel test robot
@ 2026-03-25 6:52 ` Masami Hiramatsu
2026-03-25 9:55 ` Breno Leitao
0 siblings, 1 reply; 3+ messages in thread
From: Masami Hiramatsu @ 2026-03-25 6:52 UTC (permalink / raw)
To: kernel test robot
Cc: Breno Leitao, llvm, oe-kbuild-all, Masami Hiramatsu (Google)
On Wed, 25 Mar 2026 10:37:25 +0800
kernel test robot <lkp@intel.com> wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace bootconfig/for-next
> head: 1a427f2a710583872b6176ea8378e0a1a8719fc4
> commit: 1a427f2a710583872b6176ea8378e0a1a8719fc4 [16/16] bootconfig: Apply early options from embedded config
> config: loongarch-allmodconfig (https://download.01.org/0day-ci/archive/20260325/202603251010.5Ui0yrB2-lkp@intel.com/config)
> compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260325/202603251010.5Ui0yrB2-lkp@intel.com/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@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202603251010.5Ui0yrB2-lkp@intel.com/
>
> All warnings (new ones prefixed by >>):
>
> >> init/main.c:437:20: warning: stack frame size (4192) exceeds limit (2048) in 'bootconfig_apply_early_params' [-Wframe-larger-than]
> 437 | static void __init bootconfig_apply_early_params(void)
> | ^
> 1 warning generated.
>
>
> vim +/bootconfig_apply_early_params +437 init/main.c
>
> 416
> 417 /*
> 418 * do_early_param() is defined later in this file but called from
> 419 * bootconfig_apply_early_params() below, so we need a forward declaration.
> 420 */
> 421 static int __init do_early_param(char *param, char *val,
> 422 const char *unused, void *arg);
> 423
> 424 /*
> 425 * bootconfig_apply_early_params - dispatch kernel.* keys from the embedded
> 426 * bootconfig as early_param() calls.
> 427 *
> 428 * early_param() handlers must run before most of the kernel initialises
> 429 * (e.g. before the GIC driver reads irqchip.gicv3_pseudo_nmi). A bootconfig
> 430 * attached to the initrd arrives too late for this because the initrd is not
> 431 * mapped yet when early params are processed. The embedded bootconfig lives
> 432 * in the kernel image itself (.init.data), so it is always reachable.
> 433 *
> 434 * This function is called from setup_boot_config() which runs in
> 435 * start_kernel() before parse_early_param(), making the timing correct.
> 436 */
> > 437 static void __init bootconfig_apply_early_params(void)
> 438 {
> 439 char val_buf[COMMAND_LINE_SIZE];
Ah, this COMMAND_LINE_SIZE is too big to allocate it on stack.
We need to make it as a static __initdata variable.
Thank you,
> 440 struct xbc_node *knode, *root;
> 441 const char *val;
> 442
> 443 root = xbc_find_node("kernel");
> 444 if (!root)
> 445 return;
> 446
> 447 /*
> 448 * Keys that do not match any early_param() handler are silently
> 449 * ignored — do_early_param() always returns 0.
> 450 */
> 451 xbc_node_for_each_key_value(root, knode, val) {
> 452 if (xbc_node_compose_key_after(root, knode, xbc_namebuf, XBC_KEYLEN_MAX) < 0)
> 453 continue;
> 454
> 455 if (!val) {
> 456 do_early_param(xbc_namebuf, NULL, NULL, NULL);
> 457 continue;
> 458 }
> 459
> 460 /*
> 461 * We need to copy const char *val to a char pointer,
> 462 * which is what do_early_param() need, given it might
> 463 * call strsep(), strtok() later.
> 464 */
> 465 strscpy(val_buf, val, sizeof(val_buf));
> 466 do_early_param(xbc_namebuf, val_buf, NULL, NULL);
> 467 }
> 468 }
> 469
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [trace:bootconfig/for-next 16/16] init/main.c:437:20: warning: stack frame size (4192) exceeds limit (2048) in 'bootconfig_apply_early_params'
2026-03-25 6:52 ` Masami Hiramatsu
@ 2026-03-25 9:55 ` Breno Leitao
0 siblings, 0 replies; 3+ messages in thread
From: Breno Leitao @ 2026-03-25 9:55 UTC (permalink / raw)
To: Masami Hiramatsu; +Cc: kernel test robot, llvm, oe-kbuild-all
On Wed, Mar 25, 2026 at 03:52:27PM +0900, Masami Hiramatsu wrote:
> > > 437 static void __init bootconfig_apply_early_params(void)
> > 438 {
> > 439 char val_buf[COMMAND_LINE_SIZE];
>
> Ah, this COMMAND_LINE_SIZE is too big to allocate it on stack.
> We need to make it as a static __initdata variable.
Ack, I will respin it. Thanks!
> Thank you,
>
> > 440 struct xbc_node *knode, *root;
> > 441 const char *val;
> > 442
> > 443 root = xbc_find_node("kernel");
> > 444 if (!root)
> > 445 return;
> > 446
> > 447 /*
> > 448 * Keys that do not match any early_param() handler are silently
> > 449 * ignored — do_early_param() always returns 0.
> > 450 */
> > 451 xbc_node_for_each_key_value(root, knode, val) {
> > 452 if (xbc_node_compose_key_after(root, knode, xbc_namebuf, XBC_KEYLEN_MAX) < 0)
> > 453 continue;
> > 454
> > 455 if (!val) {
I also found that val cannot be NULL here, given
xbc_node_for_each_key_value() returns an empty string ("") instead of
NULL, so, I will remove this branch here as well.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-03-25 2:37 [trace:bootconfig/for-next 16/16] init/main.c:437:20: warning: stack frame size (4192) exceeds limit (2048) in 'bootconfig_apply_early_params' kernel test robot
2026-03-25 6:52 ` Masami Hiramatsu
2026-03-25 9:55 ` Breno Leitao
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