From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, arnd@arndb.de, jeyu@kernel.org,
johannes.berg@intel.com, linux-mm@kvack.org,
mm-commits@vger.kernel.org, oberpar@linux.ibm.com,
torvalds@linux-foundation.org
Subject: [patch 08/18] init/gcov: allow CONFIG_CONSTRUCTORS on UML to fix module gcov
Date: Thu, 04 Feb 2021 18:32:28 -0800 [thread overview]
Message-ID: <20210205023228.nBf0f2zDd%akpm@linux-foundation.org> (raw)
In-Reply-To: <20210204183135.e123f0d6027529f2cf500cf2@linux-foundation.org>
From: Johannes Berg <johannes.berg@intel.com>
Subject: init/gcov: allow CONFIG_CONSTRUCTORS on UML to fix module gcov
On ARCH=um, loading a module doesn't result in its constructors getting
called, which breaks module gcov since the debugfs files are never
registered. On the other hand, in-kernel constructors have already been
called by the dynamic linker, so we can't call them again.
Get out of this conundrum by allowing CONFIG_CONSTRUCTORS to be selected,
but avoiding the in-kernel constructor calls.
Also remove the "if !UML" from GCOV selecting CONSTRUCTORS now, since we
really do want CONSTRUCTORS, just not kernel binary ones.
Link: https://lkml.kernel.org/r/20210120172041.c246a2cac2fb.I1358f584b76f1898373adfed77f4462c8705b736@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
init/Kconfig | 1 -
init/main.c | 8 +++++++-
kernel/gcov/Kconfig | 2 +-
3 files changed, 8 insertions(+), 3 deletions(-)
--- a/init/Kconfig~init-gcov-allow-config_constructors-on-uml-to-fix-module-gcov
+++ a/init/Kconfig
@@ -76,7 +76,6 @@ config CC_HAS_ASM_INLINE
config CONSTRUCTORS
bool
- depends on !UML
config IRQ_WORK
bool
--- a/init/main.c~init-gcov-allow-config_constructors-on-uml-to-fix-module-gcov
+++ a/init/main.c
@@ -1066,7 +1066,13 @@ asmlinkage __visible void __init __no_sa
/* Call all constructor functions linked into the kernel. */
static void __init do_ctors(void)
{
-#ifdef CONFIG_CONSTRUCTORS
+/*
+ * For UML, the constructors have already been called by the
+ * normal setup code as it's just a normal ELF binary, so we
+ * cannot do it again - but we do need CONFIG_CONSTRUCTORS
+ * even on UML for modules.
+ */
+#if defined(CONFIG_CONSTRUCTORS) && !defined(CONFIG_UML)
ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
for (; fn < (ctor_fn_t *) __ctors_end; fn++)
--- a/kernel/gcov/Kconfig~init-gcov-allow-config_constructors-on-uml-to-fix-module-gcov
+++ a/kernel/gcov/Kconfig
@@ -4,7 +4,7 @@ menu "GCOV-based kernel profiling"
config GCOV_KERNEL
bool "Enable gcov-based kernel profiling"
depends on DEBUG_FS
- select CONSTRUCTORS if !UML
+ select CONSTRUCTORS
default n
help
This option enables gcov-based code profiling (e.g. for code coverage
_
next prev parent reply other threads:[~2021-02-05 2:33 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-05 2:31 incoming Andrew Morton
2021-02-05 2:32 ` [patch 01/18] mm: hugetlbfs: fix cannot migrate the fallocated HugeTLB page Andrew Morton
2021-02-05 2:32 ` [patch 02/18] mm: hugetlb: fix a race between freeing and dissolving the page Andrew Morton
2021-02-05 2:32 ` [patch 03/18] mm: hugetlb: fix a race between isolating and freeing page Andrew Morton
2021-02-05 2:32 ` [patch 04/18] mm: hugetlb: remove VM_BUG_ON_PAGE from page_huge_active Andrew Morton
2021-02-05 2:32 ` [patch 05/18] mm: migrate: do not migrate HugeTLB page whose refcount is one Andrew Morton
2021-02-05 2:32 ` [patch 06/18] mm, compaction: move high_pfn to the for loop scope Andrew Morton
2021-02-05 2:32 ` [patch 07/18] mm/vmalloc: separate put pages and flush VM flags Andrew Morton
2021-02-05 2:32 ` Andrew Morton [this message]
2021-02-05 2:32 ` [patch 09/18] mm: thp: fix MADV_REMOVE deadlock on shmem THP Andrew Morton
2021-02-05 2:32 ` [patch 10/18] memblock: do not start bottom-up allocations with kernel_end Andrew Morton
2021-02-05 2:32 ` [patch 11/18] mailmap: fix name/email for Viresh Kumar Andrew Morton
2021-02-05 2:32 ` [patch 12/18] mailmap: add entries for Manivannan Sadhasivam Andrew Morton
2021-02-05 2:32 ` [patch 13/18] mm/filemap: add missing mem_cgroup_uncharge() to __add_to_page_cache_locked() Andrew Morton
2021-02-05 2:32 ` [patch 14/18] kasan: add explicit preconditions to kasan_report() Andrew Morton
2021-02-05 2:32 ` [patch 15/18] kasan: make addr_has_metadata() return true for valid addresses Andrew Morton
2021-02-05 2:32 ` [patch 16/18] ubsan: implement __ubsan_handle_alignment_assumption Andrew Morton
2021-02-05 2:33 ` [patch 17/18] mm: hugetlb: fix missing put_page in gather_surplus_pages() Andrew Morton
2021-02-05 2:33 ` [patch 18/18] MAINTAINERS/.mailmap: use my @kernel.org address Andrew Morton
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