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Consider page size in report_mmap / report_unmap.

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mmaps are full of quirks ;-)

- mmap(2) will always allocate whole memory pages, even if the
  caller only reuqests a partial page.
  This is considered by calculating the "real" size of the mmap.

- munmap(2) also operates on pages, unmapping every page it "touches.",
  so the size parameter is adjusted if needed.
This commit is contained in:
Tobias Frost 2022-06-22 12:58:56 +02:00
parent 4007678321
commit 61a32cf95e
1 changed files with 20 additions and 0 deletions
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20
report.c
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@ -241,6 +241,9 @@ static void _report_calloc(struct task *task, struct library_symbol *libsym)
report_alloc(task, MT_MALLOC, ret, size, options.bt_depth, libsym);
}
static ssize_t arch_pagesize = -1;
static void _report_mmap(struct task *task, struct library_symbol *libsym)
{
unsigned long ret = fetch_retval(task);
@ -249,6 +252,11 @@ static void _report_mmap(struct task *task, struct library_symbol *libsym)
return;
unsigned long size = fetch_param(task, 1);
if (unlikely(arch_pagesize==-1)) arch_pagesize=getpagesize();
// fixup size, if size is not a multiple of the pagesize, we get the "partial" page too. -
if (size % arch_pagesize) {
size += arch_pagesize - size % arch_pagesize;
}
report_alloc(task, MT_MMAP, ret, size, options.bt_depth, libsym);
}
@ -277,6 +285,12 @@ static void _report_mmap64(struct task *task, struct library_symbol *libsym)
else
size.l = fetch_param(task, 1);
if (unlikely(arch_pagesize == -1)) arch_pagesize=getpagesize();
// fixup size, if size is not a multiple of the pagesize, we get the "partial" page too. -
if (size.l % arch_pagesize) {
size.l += arch_pagesize - size.l % arch_pagesize;
}
report_alloc(task, MT_MMAP64, ret, size.l, options.bt_depth, libsym);
}
@ -284,6 +298,12 @@ static void report_munmap(struct task *task, struct library_symbol *libsym)
{
unsigned long addr = fetch_param(task, 0);
unsigned long size = fetch_param(task, 1);
if (unlikely(arch_pagesize==-1)) arch_pagesize=getpagesize();
// fixup size, if needed: all pages in [addr, addr+size] are unmapped -- see munmap(2)
if (size % arch_pagesize) {
size += arch_pagesize - size % arch_pagesize;
}
report_alloc(task, MT_MUNMAP, addr, size, 0, libsym);
}