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From: ben.hutchings@codethink.co.uk (Ben Hutchings)
To: cip-dev@lists.cip-project.org
Subject: [cip-dev] [PATCH 4.4-cip 07/23] ubsan: fix tree-wide -Wmaybe-uninitialized false positives
Date: Fri, 09 Dec 2016 00:35:09 +0000	[thread overview]
Message-ID: <1481243709.1860.163.camel@codethink.co.uk> (raw)
In-Reply-To: <1481243545.1860.156.camel@codethink.co.uk>

From: Andrey Ryabinin <aryabinin@virtuozzo.com>

commit dde5cf39d4d2cce71f2997c37210dd624d0e4bf6 upstream.

-fsanitize=* options makes GCC less smart than usual and increase number
of 'maybe-uninitialized' false-positives. So this patch does two things:

 * Add -Wno-maybe-uninitialized to CFLAGS_UBSAN which will disable all
   such warnings for instrumented files.

 * Remove CONFIG_UBSAN_SANITIZE_ALL from all[yes|mod]config builds. So
   the all[yes|mod]config build goes without -fsanitize=* and still with
   -Wmaybe-uninitialized.

Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
---
 lib/Kconfig.ubsan      | 5 +++++
 scripts/Makefile.ubsan | 4 ++++
 2 files changed, 9 insertions(+)

diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan
index e07c1ba9ba13..39494af9a84a 100644
--- a/lib/Kconfig.ubsan
+++ b/lib/Kconfig.ubsan
@@ -13,6 +13,11 @@ config UBSAN_SANITIZE_ALL
 	bool "Enable instrumentation for the entire kernel"
 	depends on UBSAN
 	depends on ARCH_HAS_UBSAN_SANITIZE_ALL
+
+	# We build with -Wno-maybe-uninitilzed, but we still want to
+	# use -Wmaybe-uninitilized in allmodconfig builds.
+	# So dependsy bellow used to disable this option in allmodconfig
+	depends on !COMPILE_TEST
 	default y
 	help
 	  This option activates instrumentation for the entire kernel.
diff --git a/scripts/Makefile.ubsan b/scripts/Makefile.ubsan
index 8ab68679cfb5..77ce538268b5 100644
--- a/scripts/Makefile.ubsan
+++ b/scripts/Makefile.ubsan
@@ -14,4 +14,8 @@ ifdef CONFIG_UBSAN
 ifdef CONFIG_UBSAN_ALIGNMENT
       CFLAGS_UBSAN += $(call cc-option, -fsanitize=alignment)
 endif
+
+      # -fsanitize=* options makes GCC less smart than usual and
+      # increase number of 'maybe-uninitialized false-positives
+      CFLAGS_UBSAN += $(call cc-option, -Wno-maybe-uninitialized)
 endif
-- 
2.10.2



-- 
Ben Hutchings
Software Developer, Codethink Ltd.

  parent reply	other threads:[~2016-12-09  0:35 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-09  0:32 [cip-dev] [PATCH 4.4-cip 00/23] Undefined Behaviour Sanititizer support Ben Hutchings
2016-12-09  0:33 ` [cip-dev] [PATCH 4.4-cip 01/23] UBSAN: run-time undefined behavior sanity checker Ben Hutchings
2016-12-09  0:33 ` [cip-dev] [PATCH 4.4-cip 02/23] ubsan: cosmetic fix to Kconfig text Ben Hutchings
2016-12-09  0:34 ` [cip-dev] [PATCH 4.4-cip 03/23] PM / sleep: declare __tracedata symbols as char[] rather than char Ben Hutchings
2016-12-09  0:34 ` [cip-dev] [PATCH 4.4-cip 04/23] x86/microcode/intel: Change checksum variables to u32 Ben Hutchings
2016-12-09  0:34 ` [cip-dev] [PATCH 4.4-cip 05/23] mm/page-writeback: fix dirty_ratelimit calculation Ben Hutchings
2016-12-09  0:34 ` [cip-dev] [PATCH 4.4-cip 06/23] perf/core: Fix Undefined behaviour in rb_alloc() Ben Hutchings
2016-12-09  0:35 ` Ben Hutchings [this message]
2016-12-09  0:35 ` [cip-dev] [PATCH 4.4-cip 08/23] mm/filemap: generic_file_read_iter(): check for zero reads unconditionally Ben Hutchings
2016-12-09  0:35 ` [cip-dev] [PATCH 4.4-cip 09/23] perf/x86/amd: Set the size of event map array to PERF_COUNT_HW_MAX Ben Hutchings
2016-12-09  0:35 ` [cip-dev] [PATCH 4.4-cip 10/23] drm/radeon: don't include RADEON_HPD_NONE in HPD IRQ enable bitsets Ben Hutchings
2016-12-09  0:35 ` [cip-dev] [PATCH 4.4-cip 11/23] btrfs: fix int32 overflow in shrink_delalloc() Ben Hutchings
2016-12-09  0:36 ` [cip-dev] [PATCH 4.4-cip 12/23] blk-mq: fix undefined behaviour in order_to_size() Ben Hutchings
2016-12-09  0:36 ` [cip-dev] [PATCH 4.4-cip 13/23] batman-adv: Fix integer overflow in batadv_iv_ogm_calc_tq Ben Hutchings
2016-12-09  0:36 ` [cip-dev] [PATCH 4.4-cip 14/23] signal: move the "sig < SIGRTMIN" check into siginmask(sig) Ben Hutchings
2016-12-09  0:36 ` [cip-dev] [PATCH 4.4-cip 15/23] mmc: dw_mmc: remove UBSAN warning in dw_mci_setup_bus() Ben Hutchings
2016-12-09  0:36 ` [cip-dev] [PATCH 4.4-cip 16/23] UBSAN: fix typo in format string Ben Hutchings
2016-12-09  0:37 ` [cip-dev] [PATCH 4.4-cip 17/23] rhashtable: fix shift by 64 when shrinking Ben Hutchings
2016-12-09  0:37 ` [cip-dev] [PATCH 4.4-cip 18/23] time: Avoid undefined behaviour in ktime_add_safe() Ben Hutchings
2016-12-09  0:39 ` [cip-dev] [PATCH 4.4-cip 19/23] pwm: samsung: Fix to use lowest div for large enough modulation bits Ben Hutchings
2016-12-09  0:39 ` [cip-dev] [PATCH 4.4-cip 20/23] drm: fix signed integer overflow Ben Hutchings
2016-12-09  0:39 ` [cip-dev] [PATCH 4.4-cip 21/23] xfs: " Ben Hutchings
2016-12-09  0:41 ` [cip-dev] [PATCH 4.4-cip 22/23] net: get rid of an signed integer overflow in ip_idents_reserve() Ben Hutchings
2016-12-09  0:41 ` [cip-dev] [PATCH 4.4-cip 23/23] mlx4: remove unused fields Ben Hutchings

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