+ mm-fix-memory-leak-on-mm_init-error-handling.patch added to mm-hotfixes-unstable branch

+ mm-fix-memory-leak-on-mm_init-error-handling.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm: fix memory leak on mm_init error handling
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     mm-fix-memory-leak-on-mm_init-error-handling.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-fix-memory-leak-on-mm_init-error-handling.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: mm: fix memory leak on mm_init error handling
Date: Thu, 30 Mar 2023 09:38:22 -0400

commit f1a7941243c1 ("mm: convert mm's rss stats into percpu_counter")
introduces a memory leak by missing a call to destroy_context() when a
percpu_counter fails to allocate.

Before introducing the per-cpu counter allocations, init_new_context() was
the last call that could fail in mm_init(), and thus there was no need to
ever invoke destroy_context() in the error paths.  Adding the following
percpu counter allocations adds error paths after init_new_context(),
which means its associated destroy_context() needs to be called when
percpu counters fail to allocate.

Link: https://lkml.kernel.org/r/20230330133822.66271-1-mathieu.desnoyers@efficios.com
Fixes: f1a7941243c1 ("mm: convert mm's rss stats into percpu_counter")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/fork.c |    1 +
 1 file changed, 1 insertion(+)

--- a/kernel/fork.c~mm-fix-memory-leak-on-mm_init-error-handling
+++ a/kernel/fork.c
@@ -1174,6 +1174,7 @@ static struct mm_struct *mm_init(struct
 fail_pcpu:
 	while (i > 0)
 		percpu_counter_destroy(&mm->rss_stat[--i]);
+	destroy_context(mm);
 fail_nocontext:
 	mm_free_pgd(mm);
 fail_nopgd:
_

Patches currently in -mm which might be from mathieu.desnoyers@efficios.com are

mm-fix-memory-leak-on-mm_init-error-handling.patch