diff options
| author | Jim Mussared <jim.mussared@gmail.com> | 2023-11-03 14:19:55 +1100 |
|---|---|---|
| committer | Damien George <damien@micropython.org> | 2023-11-03 16:03:18 +1100 |
| commit | b6a977848407a4ced45d118cf926bd915cc89dfb (patch) | |
| tree | 372814eb7f8234ecc5ffc3a7112ad830e69784d9 /py/objfun.c | |
| parent | c85db05244ef6185fbb3c218c508ddd179830942 (diff) | |
py/misc: Change sizeof to offsetof for variable-length alloc.
This fixes the case where e.g.
struct foo_t {
mp_obj_t x;
uint16_t y;
char buf[];
};
will have `sizeof(struct foo_t)==8`, but `offsetof(struct foo_t, buf)==6`.
When computing the size to allocate for `m_new_obj_var` we need to use
offsetof to avoid over-allocating. This is important especially when it
might cause it to spill over into another GC block.
This work was funded through GitHub Sponsors.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
Diffstat (limited to 'py/objfun.c')
| -rw-r--r-- | py/objfun.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/py/objfun.c b/py/objfun.c index 94b33cd5b..e2136968b 100644 --- a/py/objfun.c +++ b/py/objfun.c @@ -215,7 +215,7 @@ mp_code_state_t *mp_obj_fun_bc_prepare_codestate(mp_obj_t self_in, size_t n_args // RuntimeError should be raised instead. So, we use m_new_obj_var_maybe(), // return NULL, then vm.c takes the needed action (either raise // RuntimeError or fallback to stack allocation). - code_state = m_new_obj_var_maybe(mp_code_state_t, byte, state_size); + code_state = m_new_obj_var_maybe(mp_code_state_t, state, byte, state_size); if (!code_state) { return NULL; } @@ -247,10 +247,10 @@ STATIC mp_obj_t fun_bc_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const // allocate state for locals and stack mp_code_state_t *code_state = NULL; #if MICROPY_ENABLE_PYSTACK - code_state = mp_pystack_alloc(sizeof(mp_code_state_t) + state_size); + code_state = mp_pystack_alloc(offsetof(mp_code_state_t, state) + state_size); #else if (state_size > VM_MAX_STATE_ON_STACK) { - code_state = m_new_obj_var_maybe(mp_code_state_t, byte, state_size); + code_state = m_new_obj_var_maybe(mp_code_state_t, state, byte, state_size); #if MICROPY_DEBUG_VM_STACK_OVERFLOW if (code_state != NULL) { memset(code_state->state, 0, state_size); @@ -258,7 +258,7 @@ STATIC mp_obj_t fun_bc_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const #endif } if (code_state == NULL) { - code_state = alloca(sizeof(mp_code_state_t) + state_size); + code_state = alloca(offsetof(mp_code_state_t, state) + state_size); #if MICROPY_DEBUG_VM_STACK_OVERFLOW memset(code_state->state, 0, state_size); #endif @@ -320,7 +320,7 @@ STATIC mp_obj_t fun_bc_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const #else // free the state if it was allocated on the heap if (state_size != 0) { - m_del_var(mp_code_state_t, byte, state_size, code_state); + m_del_var(mp_code_state_t, state, byte, state_size, code_state); } #endif |