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Poison allocated memory when ASSERTIONS are enabled #349

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Merged
bonachea merged 1 commit into from
Jul 23, 2026
+29 −3
Merged

Poison allocated memory when ASSERTIONS are enabled #349

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32 changes: 29 additions & 3 deletions src/caffeine/allocation_s.F90
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,10 @@
#include "version.h"
#include "language-support.F90"

#ifndef CAF_POISON
#define CAF_POISON ASSERTIONS
#endif

submodule(prif:prif_private_s) allocation_s
! DO NOT ADD USE STATEMENTS HERE
! All use statements belong in prif_private_s.F90
Expand Down Expand Up @@ -39,6 +43,7 @@ module subroutine prif_allocate_coarray(lcobounds, ucobounds, size_in_bytes, &
! 15 cobounds
integer :: me
type(c_ptr) :: whole_block
integer(c_size_t) :: total_size
integer(c_ptrdiff_t) :: block_offset
integer(c_int) :: corank
type(prif_coarray_descriptor), pointer :: cdp
Expand All @@ -64,18 +69,17 @@ module subroutine prif_allocate_coarray(lcobounds, ucobounds, size_in_bytes, &
call caf_deallocate(current_team%info%heap_mspace, current_team%info%child_heap_info%allocated_memory)
end if
end if
if (me == 1) then
block
type(prif_coarray_descriptor) :: unused
integer(c_size_t) :: total_size
total_size = c_sizeof(unused) + size_in_bytes
end block
if (me == 1) then
whole_block = caf_allocate(current_team%info%heap_mspace, total_size)
if (.not. c_associated(whole_block)) then
block_offset = -1 ! out of memory
else
block_offset = as_int(whole_block) - current_team%info%heap_start
end if
end block
else
block_offset = 0
end if
Expand All @@ -93,6 +97,18 @@ module subroutine prif_allocate_coarray(lcobounds, ucobounds, size_in_bytes, &
end if
if (me /= 1) whole_block = as_c_ptr(current_team%info%heap_start + block_offset)

# if CAF_POISON
block
! The allocated memory is uninitialized, but often happens to be zero which can hide problems.
! When assertions are enabled, we poison some of the first page with non-zero values
! that are more likely to trigger failures in downstream use of uninitialized memory
integer(c_int32_t), pointer :: poison_mem(:)
call c_f_pointer(whole_block, poison_mem, [min(total_size,2048_c_size_t)/4])
poison_mem = int(z'DEADBEEF',c_int32_t)
call prif_sync_all ! must synchronize after poisoning to avoid races with subsequent RMA
end block
# endif

coarray_handle%info = whole_block ! descriptor comes first in memory
cdp => handle_to_cdp(coarray_handle)
block
Expand Down Expand Up @@ -145,6 +161,16 @@ module subroutine prif_allocate_coarray(lcobounds, ucobounds, size_in_bytes, &
call report_error(PRIF_STAT_OUT_OF_MEMORY, out_of_memory_message(size_in_bytes, .false.), &
stat, errmsg, errmsg_alloc)
else
# if CAF_POISON
block
! The allocated memory is uninitialized, but often happens to be zero which can hide problems.
! When assertions are enabled, we poison some of the first page with non-zero values
! that are more likely to trigger failures in downstream use of uninitialized memory
integer(c_int32_t), pointer :: poison_mem(:)
call c_f_pointer(mem, poison_mem, [min(size_in_bytes,2048_c_size_t)/4])
poison_mem = int(z'DECAFFED',c_int32_t)
end block
# endif
allocated_memory = mem
end if
end procedure
Expand Down
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