Re: [PATCH v3 00/35] Memory allocation profiling

Kees Cook
2024-02-13T00:29:50Z

On Mon, Feb 12, 2024 at 01:38:46PM -0800, Suren Baghdasaryan wrote:
> Low overhead [1] per-callsite memory allocation profiling. Not just for debug
> kernels, overhead low enough to be deployed in production.

What's the plan for things like devm_kmalloc() and similar relatively
simple wrappers? I was thinking it would be possible to reimplement at
least devm_kmalloc() with size and flags changing helper a while back:

https://lore.kernel.org/all/202309111428.6F36672F57@keescook/

I suspect it could be possible to adapt the alloc_hooks wrapper in this
series similarly:

#define alloc_hooks_prep(_do_alloc, _do_prepare, _do_finish, \
ctx, size, flags) \
({ \
typeof(_do_alloc) _res; \
DEFINE_ALLOC_TAG(_alloc_tag, _old); \
ssize_t _size = (size); \
size_t _usable = _size; \
gfp_t _flags = (flags); \
\
_res = _do_prepare(ctx, &_size, &_flags); \
if (!IS_ERR_OR_NULL(_res) \
_res = _do_alloc(_size, _flags); \
if (!IS_ERR_OR_NULL(_res) \
_res = _do_finish(ctx, _usable, _size, _flags, _res); \
_res; \
})

#define devm_kmalloc(dev, size, flags) \
alloc_hooks_prep(kmalloc, devm_alloc_prep, devm_alloc_finish, \
dev, size, flags)

And devm_alloc_prep() and devm_alloc_finish() adapted from the URL
above.

And _do_finish instances could be marked with __realloc_size(2)

-Kees

--
Kees Cook