diff options
| -rw-r--r-- | builder/build.go | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/builder/build.go b/builder/build.go index 8a433ca24..f17d26c72 100644 --- a/builder/build.go +++ b/builder/build.go @@ -953,15 +953,19 @@ func modifyStackSizes(executable string, stackSizeLoads []string, stackSizes map if fn.stackSizeType == stacksize.Bounded { stackSize := uint32(fn.stackSize) - // Adding 4 for the stack canary. Even though the size may be - // automatically determined, stack overflow checking is still - // important as the stack size cannot be determined for all - // goroutines. - stackSize += 4 - // Add stack size used by interrupts. switch fileHeader.Machine { case elf.EM_ARM: + if stackSize%8 != 0 { + // If the stack isn't a multiple of 8, it means the leaf + // function with the biggest stack depth doesn't have an aligned + // stack. If the STKALIGN flag is set (which it is by default) + // the interrupt controller will forcibly align the stack before + // storing in-use registers. This will thus overwrite one word + // past the end of the stack (off-by-one). + stackSize += 4 + } + // On Cortex-M (assumed here), this stack size is 8 words or 32 // bytes. This is only to store the registers that the interrupt // may modify, the interrupt will switch to the interrupt stack @@ -969,6 +973,14 @@ func modifyStackSizes(executable string, stackSizeLoads []string, stackSizes map // Some background: // https://interrupt.memfault.com/blog/cortex-m-rtos-context-switching stackSize += 32 + + // Adding 4 for the stack canary, and another 4 to keep the + // stack aligned. Even though the size may be automatically + // determined, stack overflow checking is still important as the + // stack size cannot be determined for all goroutines. + stackSize += 8 + default: + return fmt.Errorf("unknown architecture: %s", fileHeader.Machine.String()) } // Finally write the stack size to the binary. |