lib/glibc
1
0
Fork 0
mirror of https://sourceware.org/git/glibc.git synced 2025-11-05 08:10:46 +03:00
Code Activity

malloc: fix large tcache code to check for exact size match

Browse Source 
The tcache is used for allocation only if an exact match is found. In the
large tcache code added in commit cbfd798810, we currently extract a
chunk of size greater than or equal to the size we need, but don't check
strict equality. This patch fixes that behaviour.

Reviewed-by: Wilco Dijkstra  <Wilco.Dijkstra@arm.com>
This commit is contained in:
Dev Jain
2025-10-24 16:52:21 +00:00
committed by Wilco Dijkstra
parent 48e040d568
commit b2b4b46a52
1 changed files with 8 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
malloc/malloc.c
View File

@@ -3268,7 +3268,8 @@ tcache_get (size_t tc_idx)
}
static __always_inline tcache_entry **
tcache_location_large (size_t nb, size_t tc_idx, bool *mangled)
tcache_location_large (size_t nb, size_t tc_idx,
bool *mangled, tcache_entry **demangled_ptr)
{
tcache_entry **tep = &(tcache->entries[tc_idx]);
tcache_entry *te = *tep;
@@ -3280,6 +3281,7 @@ tcache_location_large (size_t nb, size_t tc_idx, bool *mangled)
*mangled = true;
}
*demangled_ptr = te;
return tep;
}
@@ -3288,7 +3290,8 @@ tcache_put_large (mchunkptr chunk, size_t tc_idx)
{
tcache_entry **entry;
bool mangled = false;
entry = tcache_location_large (chunksize (chunk), tc_idx, &mangled);
tcache_entry *te;
entry = tcache_location_large (chunksize (chunk), tc_idx, &mangled, &te);
return tcache_put_n (chunk, tc_idx, entry, mangled);
}
@@ -3298,10 +3301,10 @@ tcache_get_large (size_t tc_idx, size_t nb)
{
tcache_entry **entry;
bool mangled = false;
entry = tcache_location_large (nb, tc_idx, &mangled);
tcache_entry *te;
entry = tcache_location_large (nb, tc_idx, &mangled, &te);
if ((mangled && REVEAL_PTR (*entry) == NULL)
|| (!mangled && *entry == NULL))
if (te == NULL || nb != chunksize (mem2chunk (te)))
return NULL;
return tcache_get_n (tc_idx, entry, mangled);