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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Michal Hocko <mhocko@suse.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 01/25] include/linux/mmdebug.h: make VM_WARN* non-rvals
Date: Fri,  9 Jul 2021 15:18:32 +0200	[thread overview]
Message-ID: <20210709131628.757242241@linuxfoundation.org> (raw)
In-Reply-To: <20210709131627.928131764@linuxfoundation.org>

From: Michal Hocko <mhocko@kernel.org>

[ Upstream commit 91241681c62a5a690c88eb2aca027f094125eaac ]

At present the construct

	if (VM_WARN(...))

will compile OK with CONFIG_DEBUG_VM=y and will fail with
CONFIG_DEBUG_VM=n.  The reason is that VM_{WARN,BUG}* have always been
special wrt.  {WARN/BUG}* and never generate any code when DEBUG_VM is
disabled.  So we cannot really use it in conditionals.

We considered changing things so that this construct works in both cases
but that might cause unwanted code generation with CONFIG_DEBUG_VM=n.
It is safer and simpler to make the build fail in both cases.

[akpm@linux-foundation.org: changelog]
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/mmdebug.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index 57b0030d3800..2ad72d2c8cc5 100644
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -37,10 +37,10 @@ void dump_mm(const struct mm_struct *mm);
 			BUG();						\
 		}							\
 	} while (0)
-#define VM_WARN_ON(cond) WARN_ON(cond)
-#define VM_WARN_ON_ONCE(cond) WARN_ON_ONCE(cond)
-#define VM_WARN_ONCE(cond, format...) WARN_ONCE(cond, format)
-#define VM_WARN(cond, format...) WARN(cond, format)
+#define VM_WARN_ON(cond) (void)WARN_ON(cond)
+#define VM_WARN_ON_ONCE(cond) (void)WARN_ON_ONCE(cond)
+#define VM_WARN_ONCE(cond, format...) (void)WARN_ONCE(cond, format)
+#define VM_WARN(cond, format...) (void)WARN(cond, format)
 #else
 #define VM_BUG_ON(cond) BUILD_BUG_ON_INVALID(cond)
 #define VM_BUG_ON_PAGE(cond, page) VM_BUG_ON(cond)
-- 
2.30.2




  reply	other threads:[~2021-07-09 13:19 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-09 13:18 [PATCH 4.14 00/25] 4.14.239-rc1 review Greg Kroah-Hartman
2021-07-09 13:18 ` Greg Kroah-Hartman [this message]
2021-07-09 13:18 ` [PATCH 4.14 02/25] mm: add VM_WARN_ON_ONCE_PAGE() macro Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 03/25] mm/rmap: remove unneeded semicolon in page_not_mapped() Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 04/25] mm/rmap: use page_not_mapped in try_to_unmap() Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 05/25] mm/thp: try_to_unmap() use TTU_SYNC for safe splitting Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 06/25] mm/thp: fix vma_address() if virtual address below file offset Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 07/25] mm/thp: fix page_address_in_vma() on file THP tails Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 08/25] mm: thp: replace DEBUG_VM BUG with VM_WARN when unmap fails for split Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 09/25] mm: page_vma_mapped_walk(): use page for pvmw->page Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 10/25] mm: page_vma_mapped_walk(): settle PageHuge on entry Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 11/25] mm: page_vma_mapped_walk(): use pmde for *pvmw->pmd Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 12/25] mm: page_vma_mapped_walk(): prettify PVMW_MIGRATION block Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 13/25] mm: page_vma_mapped_walk(): crossing page table boundary Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 14/25] mm: page_vma_mapped_walk(): add a level of indentation Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 15/25] mm: page_vma_mapped_walk(): use goto instead of while (1) Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 16/25] mm: page_vma_mapped_walk(): get vma_address_end() earlier Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 17/25] mm/thp: fix page_vma_mapped_walk() if THP mapped by ptes Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 18/25] mm/thp: another PVMW_SYNC fix in page_vma_mapped_walk() Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 19/25] mm, futex: fix shared futex pgoff on shmem huge page Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 20/25] scsi: sr: Return appropriate error code when disk is ejected Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 21/25] drm/nouveau: fix dma_address check for CPU/GPU sync Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 22/25] kfifo: DECLARE_KIFO_PTR(fifo, u64) does not work on arm 32 bit Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 23/25] kthread_worker: split code for canceling the delayed work timer Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 24/25] kthread: prevent deadlock when kthread_mod_delayed_work() races with kthread_cancel_delayed_work_sync() Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 25/25] xen/events: reset active flag for lateeoi events later Greg Kroah-Hartman
2021-07-10 14:05 ` [PATCH 4.14 00/25] 4.14.239-rc1 review Naresh Kamboju
2021-07-10 19:51 ` Guenter Roeck
2021-07-12  0:57 ` Samuel Zou

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