Re: [PATCH] net: mana: Fix memory leak in mana_gd_setup_irqs

[Jakub Kicinski]

On Thu, 28 Nov 2024 18:13:25 -0800 Yury Norov wrote:
> > FWIW, there's a related error path leak. If the kcalloc() to populate
> > gc->irq_contexts fails, the irqs array is not freed. Probably could
> > extend this patch to fix that leak as well.
> > 
> > Michael  
> 
> That's why we've got a __free() macro in include/linux/cleanup.h

Quoting documentation:

  Using device-managed and cleanup.h constructs
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  
  Netdev remains skeptical about promises of all "auto-cleanup" APIs,
  including even ``devm_`` helpers, historically. They are not the preferred
  style of implementation, merely an acceptable one.
  
  Use of ``guard()`` is discouraged within any function longer than 20 lines,
  ``scoped_guard()`` is considered more readable. Using normal lock/unlock is
  still (weakly) preferred.
  
  Low level cleanup constructs (such as ``__free()``) can be used when building
  APIs and helpers, especially scoped iterators. However, direct use of
  ``__free()`` within networking core and drivers is discouraged.
  Similar guidance applies to declaring variables mid-function.
  
See: https://www.kernel.org/doc/html/next/process/maintainer-netdev.html#using-device-managed-and-cleanup-h-constructs