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u3: move the guard page earlier when making roads (#479)

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... preventing spurious `loom: ward bogus` assertion failures. The guard
page was being moved if necessary after initializing an inner road
(accounting for road padding), but it could still be hit while
initializing the road struct itself, in which case it would trigger an
guard-page sanity assertion.
This commit is contained in:
Joe Bryan 2023-06-30 12:41:00 -04:00 committed by GitHub
commit aeca0c0818
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 11 additions and 5 deletions
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2
pkg/noun/events.c
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@ -1715,7 +1715,7 @@ u3e_ward(u3_post low_p, u3_post hig_p)
c3_w sop_w = hig_p >> u3a_page;
c3_w pag_w = u3P.gar_w;
if ( !((pag_w > nop_w) && (pag_w < hig_p)) ) {
if ( !((pag_w > nop_w) && (pag_w < sop_w)) ) {
u3_assert( !_ce_ward_post(nop_w, sop_w) );
u3_assert( !_ce_flaw_mprotect(pag_w) );
u3_assert( u3P.dit_w[pag_w >> 5] & (1 << (pag_w & 31)) );

14
pkg/noun/manage.c
View File

@ -518,7 +518,7 @@ _pave_road(c3_w* rut_w, c3_w* mat_w, c3_w* cap_w, c3_w siz_w)
len_w - size of your loom in words
*/
static u3_road*
_pave_north(c3_w* mem_w, c3_w siz_w, c3_w len_w)
_pave_north(c3_w* mem_w, c3_w siz_w, c3_w len_w, c3_o kid_o)
{
// in a north road, the heap is low and the stack is high
//
@ -533,6 +533,10 @@ _pave_north(c3_w* mem_w, c3_w siz_w, c3_w len_w)
c3_w* rut_w = c3_align(mem_w, u3C.balign_d, C3_ALGHI);
c3_w* cap_w = mat_w;
if ( c3y == kid_o ) {
u3e_ward(u3of(c3_w, rut_w) - 1, u3of(c3_w, cap_w));
}
return _pave_road(rut_w, mat_w, cap_w, siz_w);
}
@ -555,10 +559,13 @@ _pave_south(c3_w* mem_w, c3_w siz_w, c3_w len_w)
//
// 00~~~|M|+++|C|######|H|---|R|~~~FFF
// ^---u3R which _pave_road returns
//
c3_w* mat_w = c3_align(mem_w, u3C.balign_d, C3_ALGHI);
c3_w* rut_w = c3_align(mem_w + len_w, u3C.balign_d, C3_ALGLO);
c3_w* cap_w = mat_w + siz_w;
u3e_ward(u3of(c3_w, cap_w) - 1, u3of(c3_w, rut_w));
return _pave_road(rut_w, mat_w, cap_w, siz_w);
}
@ -574,7 +581,7 @@ _pave_home(void)
c3_w siz_w = c3_wiseof(u3v_home);
c3_w len_w = u3C.wor_i - u3C.walign_w;
u3H = (void *)_pave_north(mem_w, siz_w, len_w);
u3H = (void *)_pave_north(mem_w, siz_w, len_w, c3n);
u3H->ver_w = U3V_VERLAT;
u3R = &u3H->rod_u;
@ -879,7 +886,7 @@ u3m_leap(c3_w pad_w)
else {
bot_p = u3R->cap_p;
rod_u = _pave_north(u3a_into(bot_p), c3_wiseof(u3a_road), len_w);
rod_u = _pave_north(u3a_into(bot_p), c3_wiseof(u3a_road), len_w, c3y);
#if 0
fprintf(stderr, "SPAR.hat_p: 0x%x %p, NKID.hat_p: 0x%x %p\r\n",
u3R->hat_p, u3a_into(u3R->hat_p),
@ -901,7 +908,6 @@ u3m_leap(c3_w pad_w)
*/
{
u3R = rod_u;
u3m_ward();
_pave_parts();
}
#ifdef U3_MEMORY_DEBUG