suoyuanG opened a new pull request, #17054:
URL: https://github.com/apache/nuttx/pull/17054
## Summary
Added nxsched_switch_context for unified context switching.
Base on this, I made a software method for stack overflow detection, which
will detect the sp register and the bottom stack memory of the thread.
## Impact
Add stack overflow detection on context switching. If enable
`STACKCHECK_SOFTWARE`, this check will be turned on. By default, the bottom 16
bytes of the stack will be checked. This parameter can be configured through
`STACKCHECK_MARGIN`
## Testing
```c
#include <pthread.h>
#include <sched.h>
#include <stdint.h>
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#define STACK_SIZE (8192)
static unsigned char stack[STACK_SIZE];
void *thread_func(void *arg) {
puts("haha");
return NULL;
}
int main(int argc, char *argv[]) {
pthread_t thread;
pthread_attr_t attr;
uint32_t stack_color = 0xdeadbeef;
pthread_attr_init(&attr);
pthread_attr_setstack(&attr, stack, STACK_SIZE);
printf("stack: %p\n", stack);
if (pthread_create(&thread, &attr, thread_func, NULL) != 0) {
perror("pthread_create");
return 1;
}
const uintptr_t stack_bottom_align = ((uintptr_t)stack);
uint32_t *start = (uint32_t *)stack_bottom_align;
const uint32_t *end = (uint32_t *)(stack + STACK_SIZE - sizeof(uint32_t));
int found = 0;
for (; start <= end; ++start) {
if (*start == stack_color) {
*start = 0xabcdabcd;
printf("fetch the stack color: %p\n", start);
found = 1;
break;
}
}
pthread_join(thread, NULL);
if (!found) {
fprintf(stderr, "stack color not found\n");
}
pthread_attr_destroy(&attr);
return 0;
}
```
```bash
$ qemu-system-arm -cpu cortex-a7 -nographic -machine virt -kernel build/nuttx
NuttShell (NSH) NuttX-12.10.0
nsh> stack_canarytest
stack: 0x40005278
fetch the stack color: 0x40005288
haha
dump_assert_info: Current Version: NuttX 12.10.0 0d62d83134-dirty Sep 22
2025 14:40:52 arm
dump_assert_info: Assertion failed : at file:
/sched/sched/sched_switchcontext.c:60 task: stack_canarytest process:
stack_canarytest 0x18994
up_dump_register: R0: 400034b0 R1: 00000001 R2: 00000000 R3: 00000000
up_dump_register: R4: 4000bb28 R5: 4000bb28 R6: 400034b0 R7: 00000000
up_dump_register: R8: 000370d2 SB: 40002d50 SL: 00000006 FP: 0000003c
up_dump_register: IP: 40002dc4 SP: 40007130 LR: 00005e50 PC: 00005e50
up_dump_register: CPSR: 600000df
```
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