git/linux-cryptodev-2.6
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git synced 2026-04-04 04:37:39 -04:00
Code Issues Packages Projects Releases Wiki Activity

slab.h: disable completely broken overflow handling in flex allocations

Browse Source 
Commit 69050f8d6d ("treewide: Replace kmalloc with kmalloc_obj for
non-scalar types") started using the new allocation helpers, and in the
process showed that they were completely non-working.

The overflow logic in overflows_flex_counter_type() is completely the
wrong way around, and that broke __alloc_flex() completely.  By chance,
the resulting code was then such a mess that clang generated
sufficiently garbage code that objtool warned about it all.  Which made
it somewhat quicker to narrow things down.

While fixing overflows_flex_counter_type() would presumably fix this
all, I'm excising the whole broken overflow logic from __alloc_flex(),
because we don't want that kind of code in basic allocation functions
anyway.

That (no longer) broken overflows_flex_counter_type() thing needs to be
inserted into the actual __set_flex_counter() logic in the unlikely case
that we ever want this at all.  And made conditional.

Fixes: 81cee9166a ("compiler_types: Introduce __flex_counter() and family")
Fixes: 69050f8d6d ("treewide: Replace kmalloc with kmalloc_obj for non-scalar types")
Cc: Kees Cook <kees@kernel.org>
Link: https://lore.kernel.org/all/CAHk-=whEd020BYzGTzYrENjD9Z5_82xx6h8HsQvH5xDSnv0=Hw@mail.gmail.com/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds
2026-02-21 15:12:09 -08:00
parent 8934827db5
commit fa5c82f4d2
2 changed files with 2 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/overflow.h
View File

@@ -570,7 +570,7 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend)
* @FAM is not annotated with __counted_by(), always returns true.
*/
#define overflows_flex_counter_type(TYPE, FAM, COUNT) \
(!overflows_type(COUNT, typeof_flex_counter(((TYPE *)NULL)->FAM)))
(overflows_type(COUNT, typeof_flex_counter(((TYPE *)NULL)->FAM)))
/**
* __set_flex_counter() - Set the counter associated with the given flexible

6
include/linux/slab.h
View File

@@ -1003,11 +1003,7 @@ void *kmalloc_nolock_noprof(size_t size, gfp_t gfp_flags, int node);
({ \
const size_t __count = (COUNT); \
const size_t __obj_size = struct_size_t(TYPE, FAM, __count); \
TYPE *__obj_ptr; \
if (WARN_ON_ONCE(overflows_flex_counter_type(TYPE, FAM, __count))) \
__obj_ptr = NULL; \
else \
__obj_ptr = KMALLOC(__obj_size, GFP); \
TYPE *__obj_ptr = KMALLOC(__obj_size, GFP); \
if (__obj_ptr) \
__set_flex_counter(__obj_ptr->FAM, __count); \
__obj_ptr; \