From 7ed1c1901fe52e6c5828deb155920b44b0adabb1 Mon Sep 17 00:00:00 2001 From: Martin Kelly Date: Wed, 21 Feb 2018 14:45:12 -0800 Subject: tools: fix cross-compile var clobbering Currently a number of Makefiles break when used with toolchains that pass extra flags in CC and other cross-compile related variables (such as --sysroot). Thus we get this error when we use a toolchain that puts --sysroot in the CC var: ~/src/linux/tools$ make iio [snip] iio_event_monitor.c:18:10: fatal error: unistd.h: No such file or directory #include ^~~~~~~~~~ This occurs because we clobber several env vars related to cross-compiling with lines like this: CC = $(CROSS_COMPILE)gcc Although this will point to a valid cross-compiler, we lose any extra flags that might exist in the CC variable, which can break toolchains that rely on them (for example, those that use --sysroot). This easily shows up using a Yocto SDK: $ . [snip]/sdk/environment-setup-cortexa8hf-neon-poky-linux-gnueabi $ echo $CC arm-poky-linux-gnueabi-gcc -march=armv7-a -mfpu=neon -mfloat-abi=hard -mcpu=cortex-a8 --sysroot=[snip]/sdk/sysroots/cortexa8hf-neon-poky-linux-gnueabi $ echo $CROSS_COMPILE arm-poky-linux-gnueabi- $ echo ${CROSS_COMPILE}gcc krm-poky-linux-gnueabi-gcc Although arm-poky-linux-gnueabi-gcc is a cross-compiler, we've lost the --sysroot and other flags that enable us to find the right libraries to link against, so we can't find unistd.h and other libraries and headers. Normally with the --sysroot flag we would find unistd.h in the sdk directory in the sysroot: $ find [snip]/sdk/sysroots -path '*/usr/include/unistd.h' [snip]/sdk/sysroots/cortexa8hf-neon-poky-linux-gnueabi/usr/include/unistd.h The perf Makefile adds CC = $(CROSS_COMPILE)gcc if and only if CC is not already set, and it compiles correctly with the above toolchain. So, generalize the logic that perf uses in the common Makefile and remove the manual CC = $(CROSS_COMPILE)gcc lines from each Makefile. Note that this patch does not fix cross-compile for all the tools (some have other bugs), but it does fix it for all except usb and acpi, which still have other unrelated issues. I tested both with and without the patch on native and cross-build and there appear to be no regressions. Link: http://lkml.kernel.org/r/20180107214028.23771-1-martin@martingkelly.com Signed-off-by: Martin Kelly Acked-by: Mark Brown Cc: Tejun Heo Cc: Li Zefan Cc: Johannes Weiner Cc: Linus Walleij Cc: "K. Y. Srinivasan" Cc: Haiyang Zhang Cc: Stephen Hemminger Cc: Jonathan Cameron Cc: Pali Rohar Cc: Richard Purdie Cc: Jacek Anaszewski Cc: Pavel Machek Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Cc: Robert Moore Cc: Lv Zheng Cc: "Rafael J. Wysocki" Cc: Greg Kroah-Hartman Cc: Valentina Manea Cc: Shuah Khan Cc: Mario Limonciello Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- tools/cgroup/Makefile | 1 - tools/gpio/Makefile | 2 -- tools/hv/Makefile | 1 - tools/iio/Makefile | 2 -- tools/laptop/freefall/Makefile | 1 - tools/leds/Makefile | 1 - tools/perf/Makefile.perf | 6 ------ tools/power/acpi/Makefile.config | 3 --- tools/scripts/Makefile.include | 18 ++++++++++++++++++ tools/spi/Makefile | 2 -- tools/usb/Makefile | 1 - tools/vm/Makefile | 1 - tools/wmi/Makefile | 1 - 13 files changed, 18 insertions(+), 22 deletions(-) diff --git a/tools/cgroup/Makefile b/tools/cgroup/Makefile index 860fa151640a..ffca068e4a76 100644 --- a/tools/cgroup/Makefile +++ b/tools/cgroup/Makefile @@ -1,7 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 # Makefile for cgroup tools -CC = $(CROSS_COMPILE)gcc CFLAGS = -Wall -Wextra all: cgroup_event_listener diff --git a/tools/gpio/Makefile b/tools/gpio/Makefile index 805a2c0cf4cd..240eda014b37 100644 --- a/tools/gpio/Makefile +++ b/tools/gpio/Makefile @@ -12,8 +12,6 @@ endif # (this improves performance and avoids hard-to-debug behaviour); MAKEFLAGS += -r -CC = $(CROSS_COMPILE)gcc -LD = $(CROSS_COMPILE)ld CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include ALL_TARGETS := lsgpio gpio-hammer gpio-event-mon diff --git a/tools/hv/Makefile b/tools/hv/Makefile index 1139d71fa0cf..5db5e62cebda 100644 --- a/tools/hv/Makefile +++ b/tools/hv/Makefile @@ -1,7 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 # Makefile for Hyper-V tools -CC = $(CROSS_COMPILE)gcc WARNINGS = -Wall -Wextra CFLAGS = $(WARNINGS) -g $(shell getconf LFS_CFLAGS) diff --git a/tools/iio/Makefile b/tools/iio/Makefile index a08e7a47d6a3..332ed2f6c2c2 100644 --- a/tools/iio/Makefile +++ b/tools/iio/Makefile @@ -12,8 +12,6 @@ endif # (this improves performance and avoids hard-to-debug behaviour); MAKEFLAGS += -r -CC = $(CROSS_COMPILE)gcc -LD = $(CROSS_COMPILE)ld CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include ALL_TARGETS := iio_event_monitor lsiio iio_generic_buffer diff --git a/tools/laptop/freefall/Makefile b/tools/laptop/freefall/Makefile index 5f758c489a20..b572d94255f6 100644 --- a/tools/laptop/freefall/Makefile +++ b/tools/laptop/freefall/Makefile @@ -2,7 +2,6 @@ PREFIX ?= /usr SBINDIR ?= sbin INSTALL ?= install -CC = $(CROSS_COMPILE)gcc TARGET = freefall diff --git a/tools/leds/Makefile b/tools/leds/Makefile index c379af003807..7b6bed13daaa 100644 --- a/tools/leds/Makefile +++ b/tools/leds/Makefile @@ -1,7 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 # Makefile for LEDs tools -CC = $(CROSS_COMPILE)gcc CFLAGS = -Wall -Wextra -g -I../../include/uapi all: uledmon led_hw_brightness_mon diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf index 9b0351d3ce34..012328038594 100644 --- a/tools/perf/Makefile.perf +++ b/tools/perf/Makefile.perf @@ -146,12 +146,6 @@ define allow-override $(eval $(1) = $(2))) endef -# Allow setting CC and AR and LD, or setting CROSS_COMPILE as a prefix. -$(call allow-override,CC,$(CROSS_COMPILE)gcc) -$(call allow-override,AR,$(CROSS_COMPILE)ar) -$(call allow-override,LD,$(CROSS_COMPILE)ld) -$(call allow-override,CXX,$(CROSS_COMPILE)g++) - LD += $(EXTRA_LDFLAGS) HOSTCC ?= gcc diff --git a/tools/power/acpi/Makefile.config b/tools/power/acpi/Makefile.config index a1883bbb0144..2cccbba64418 100644 --- a/tools/power/acpi/Makefile.config +++ b/tools/power/acpi/Makefile.config @@ -56,9 +56,6 @@ INSTALL_SCRIPT = ${INSTALL_PROGRAM} # to compile vs uClibc, that can be done here as well. CROSS = #/usr/i386-linux-uclibc/usr/bin/i386-uclibc- CROSS_COMPILE ?= $(CROSS) -CC = $(CROSS_COMPILE)gcc -LD = $(CROSS_COMPILE)gcc -STRIP = $(CROSS_COMPILE)strip HOSTCC = gcc # check if compiler option is supported diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.include index fcb3ed0be5f8..dd614463d4d6 100644 --- a/tools/scripts/Makefile.include +++ b/tools/scripts/Makefile.include @@ -42,6 +42,24 @@ EXTRA_WARNINGS += -Wformat CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?) +# Makefiles suck: This macro sets a default value of $(2) for the +# variable named by $(1), unless the variable has been set by +# environment or command line. This is necessary for CC and AR +# because make sets default values, so the simpler ?= approach +# won't work as expected. +define allow-override + $(if $(or $(findstring environment,$(origin $(1))),\ + $(findstring command line,$(origin $(1)))),,\ + $(eval $(1) = $(2))) +endef + +# Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix. +$(call allow-override,CC,$(CROSS_COMPILE)gcc) +$(call allow-override,AR,$(CROSS_COMPILE)ar) +$(call allow-override,LD,$(CROSS_COMPILE)ld) +$(call allow-override,CXX,$(CROSS_COMPILE)g++) +$(call allow-override,STRIP,$(CROSS_COMPILE)strip) + ifeq ($(CC_NO_CLANG), 1) EXTRA_WARNINGS += -Wstrict-aliasing=3 endif diff --git a/tools/spi/Makefile b/tools/spi/Makefile index 90615e10c79a..815d15589177 100644 --- a/tools/spi/Makefile +++ b/tools/spi/Makefile @@ -11,8 +11,6 @@ endif # (this improves performance and avoids hard-to-debug behaviour); MAKEFLAGS += -r -CC = $(CROSS_COMPILE)gcc -LD = $(CROSS_COMPILE)ld CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include ALL_TARGETS := spidev_test spidev_fdx diff --git a/tools/usb/Makefile b/tools/usb/Makefile index 4e6506078494..01d758d73b6d 100644 --- a/tools/usb/Makefile +++ b/tools/usb/Makefile @@ -1,7 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 # Makefile for USB tools -CC = $(CROSS_COMPILE)gcc PTHREAD_LIBS = -lpthread WARNINGS = -Wall -Wextra CFLAGS = $(WARNINGS) -g -I../include diff --git a/tools/vm/Makefile b/tools/vm/Makefile index be320b905ea7..20f6cf04377f 100644 --- a/tools/vm/Makefile +++ b/tools/vm/Makefile @@ -6,7 +6,6 @@ TARGETS=page-types slabinfo page_owner_sort LIB_DIR = ../lib/api LIBS = $(LIB_DIR)/libapi.a -CC = $(CROSS_COMPILE)gcc CFLAGS = -Wall -Wextra -I../lib/ LDFLAGS = $(LIBS) diff --git a/tools/wmi/Makefile b/tools/wmi/Makefile index e664f1167388..e0e87239126b 100644 --- a/tools/wmi/Makefile +++ b/tools/wmi/Makefile @@ -2,7 +2,6 @@ PREFIX ?= /usr SBINDIR ?= sbin INSTALL ?= install CFLAGS += -D__EXPORTED_HEADERS__ -I../../include/uapi -I../../include -CC = $(CROSS_COMPILE)gcc TARGET = dell-smbios-example -- cgit v1.2.3 From d34bc48f8275b6ce0da44f639d68344891268ee9 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Wed, 21 Feb 2018 14:45:17 -0800 Subject: include/linux/sched/mm.h: re-inline mmdrop() As Peter points out, Doing a CALL+RET for just the decrement is a bit silly. Fixes: d70f2a14b72a4bc ("include/linux/sched/mm.h: uninline mmdrop_async(), etc") Acked-by: Peter Zijlstra (Intel) Cc: Ingo Molnar Cc: Michal Hocko Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/sched/mm.h | 13 ++++++++++++- kernel/fork.c | 15 ++------------- 2 files changed, 14 insertions(+), 14 deletions(-) diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index 1149533aa2fa..9806184bb3d5 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -36,7 +36,18 @@ static inline void mmgrab(struct mm_struct *mm) atomic_inc(&mm->mm_count); } -extern void mmdrop(struct mm_struct *mm); +extern void __mmdrop(struct mm_struct *mm); + +static inline void mmdrop(struct mm_struct *mm) +{ + /* + * The implicit full barrier implied by atomic_dec_and_test() is + * required by the membarrier system call before returning to + * user-space, after storing to rq->curr. + */ + if (unlikely(atomic_dec_and_test(&mm->mm_count))) + __mmdrop(mm); +} /** * mmget() - Pin the address space associated with a &struct mm_struct. diff --git a/kernel/fork.c b/kernel/fork.c index be8aa5b98666..e5d9d405ae4e 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -592,7 +592,7 @@ static void check_mm(struct mm_struct *mm) * is dropped: either by a lazy thread or by * mmput. Free the page directory and the mm. */ -static void __mmdrop(struct mm_struct *mm) +void __mmdrop(struct mm_struct *mm) { BUG_ON(mm == &init_mm); mm_free_pgd(mm); @@ -603,18 +603,7 @@ static void __mmdrop(struct mm_struct *mm) put_user_ns(mm->user_ns); free_mm(mm); } - -void mmdrop(struct mm_struct *mm) -{ - /* - * The implicit full barrier implied by atomic_dec_and_test() is - * required by the membarrier system call before returning to - * user-space, after storing to rq->curr. - */ - if (unlikely(atomic_dec_and_test(&mm->mm_count))) - __mmdrop(mm); -} -EXPORT_SYMBOL_GPL(mmdrop); +EXPORT_SYMBOL_GPL(__mmdrop); static void mmdrop_async_fn(struct work_struct *work) { -- cgit v1.2.3 From 101110f6271ce956a049250c907bc960030577f8 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 21 Feb 2018 14:45:20 -0800 Subject: Kbuild: always define endianess in kconfig.h Build testing with LTO found a couple of files that get compiled differently depending on whether asm/byteorder.h gets included early enough or not. In particular, include/asm-generic/qrwlock_types.h is affected by this, but there are probably others as well. The symptom is a series of LTO link time warnings, including these: net/netlabel/netlabel_unlabeled.h:223: error: type of 'netlbl_unlhsh_add' does not match original declaration [-Werror=lto-type-mismatch] int netlbl_unlhsh_add(struct net *net, net/netlabel/netlabel_unlabeled.c:377: note: 'netlbl_unlhsh_add' was previously declared here include/net/ipv6.h:360: error: type of 'ipv6_renew_options_kern' does not match original declaration [-Werror=lto-type-mismatch] ipv6_renew_options_kern(struct sock *sk, net/ipv6/exthdrs.c:1162: note: 'ipv6_renew_options_kern' was previously declared here net/core/dev.c:761: note: 'dev_get_by_name_rcu' was previously declared here struct net_device *dev_get_by_name_rcu(struct net *net, const char *name) net/core/dev.c:761: note: code may be misoptimized unless -fno-strict-aliasing is used drivers/gpu/drm/i915/i915_drv.h:3377: error: type of 'i915_gem_object_set_to_wc_domain' does not match original declaration [-Werror=lto-type-mismatch] i915_gem_object_set_to_wc_domain(struct drm_i915_gem_object *obj, bool write); drivers/gpu/drm/i915/i915_gem.c:3639: note: 'i915_gem_object_set_to_wc_domain' was previously declared here include/linux/debugfs.h:92:9: error: type of 'debugfs_attr_read' does not match original declaration [-Werror=lto-type-mismatch] ssize_t debugfs_attr_read(struct file *file, char __user *buf, fs/debugfs/file.c:318: note: 'debugfs_attr_read' was previously declared here include/linux/rwlock_api_smp.h:30: error: type of '_raw_read_unlock' does not match original declaration [-Werror=lto-type-mismatch] void __lockfunc _raw_read_unlock(rwlock_t *lock) __releases(lock); kernel/locking/spinlock.c:246:26: note: '_raw_read_unlock' was previously declared here include/linux/fs.h:3308:5: error: type of 'simple_attr_open' does not match original declaration [-Werror=lto-type-mismatch] int simple_attr_open(struct inode *inode, struct file *file, fs/libfs.c:795: note: 'simple_attr_open' was previously declared here All of the above are caused by include/asm-generic/qrwlock_types.h failing to include asm/byteorder.h after commit e0d02285f16e ("locking/qrwlock: Use 'struct qrwlock' instead of 'struct __qrwlock'") in linux-4.15. Similar bugs may or may not exist in older kernels as well, but there is no easy way to test those with link-time optimizations, and kernels before 4.14 are harder to fix because they don't have Babu's patch series We had similar issues with CONFIG_ symbols in the past and ended up always including the configuration headers though linux/kconfig.h. This works around the issue through that same file, defining either __BIG_ENDIAN or __LITTLE_ENDIAN depending on CONFIG_CPU_BIG_ENDIAN, which is now always set on all architectures since commit 4c97a0c8fee3 ("arch: define CPU_BIG_ENDIAN for all fixed big endian archs"). Link: http://lkml.kernel.org/r/20180202154104.1522809-2-arnd@arndb.de Signed-off-by: Arnd Bergmann Cc: Babu Moger Cc: Andi Kleen Cc: Greg Kroah-Hartman Cc: Masahiro Yamada Cc: Nicolas Pitre Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kconfig.h | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/include/linux/kconfig.h b/include/linux/kconfig.h index fec5076eda91..cc8fa109cfa3 100644 --- a/include/linux/kconfig.h +++ b/include/linux/kconfig.h @@ -4,6 +4,12 @@ #include +#ifdef CONFIG_CPU_BIG_ENDIAN +#define __BIG_ENDIAN 4321 +#else +#define __LITTLE_ENDIAN 1234 +#endif + #define __ARG_PLACEHOLDER_1 0, #define __take_second_arg(__ignored, val, ...) val -- cgit v1.2.3 From c3cc39118c3610eb6ab4711bc624af7fc48a35fe Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Wed, 21 Feb 2018 14:45:24 -0800 Subject: mm: memcontrol: fix NR_WRITEBACK leak in memcg and system stats After commit a983b5ebee57 ("mm: memcontrol: fix excessive complexity in memory.stat reporting"), we observed slowly upward creeping NR_WRITEBACK counts over the course of several days, both the per-memcg stats as well as the system counter in e.g. /proc/meminfo. The conversion from full per-cpu stat counts to per-cpu cached atomic stat counts introduced an irq-unsafe RMW operation into the updates. Most stat updates come from process context, but one notable exception is the NR_WRITEBACK counter. While writebacks are issued from process context, they are retired from (soft)irq context. When writeback completions interrupt the RMW counter updates of new writebacks being issued, the decs from the completions are lost. Since the global updates are routed through the joint lruvec API, both the memcg counters as well as the system counters are affected. This patch makes the joint stat and event API irq safe. Link: http://lkml.kernel.org/r/20180203082353.17284-1-hannes@cmpxchg.org Fixes: a983b5ebee57 ("mm: memcontrol: fix excessive complexity in memory.stat reporting") Signed-off-by: Johannes Weiner Debugged-by: Tejun Heo Reviewed-by: Rik van Riel Reviewed-by: Andrew Morton Cc: Vladimir Davydov Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 882046863581..c46016bb25eb 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -523,9 +523,11 @@ static inline void __mod_memcg_state(struct mem_cgroup *memcg, static inline void mod_memcg_state(struct mem_cgroup *memcg, int idx, int val) { - preempt_disable(); + unsigned long flags; + + local_irq_save(flags); __mod_memcg_state(memcg, idx, val); - preempt_enable(); + local_irq_restore(flags); } /** @@ -606,9 +608,11 @@ static inline void __mod_lruvec_state(struct lruvec *lruvec, static inline void mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx, int val) { - preempt_disable(); + unsigned long flags; + + local_irq_save(flags); __mod_lruvec_state(lruvec, idx, val); - preempt_enable(); + local_irq_restore(flags); } static inline void __mod_lruvec_page_state(struct page *page, @@ -630,9 +634,11 @@ static inline void __mod_lruvec_page_state(struct page *page, static inline void mod_lruvec_page_state(struct page *page, enum node_stat_item idx, int val) { - preempt_disable(); + unsigned long flags; + + local_irq_save(flags); __mod_lruvec_page_state(page, idx, val); - preempt_enable(); + local_irq_restore(flags); } unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, @@ -659,9 +665,11 @@ static inline void __count_memcg_events(struct mem_cgroup *memcg, static inline void count_memcg_events(struct mem_cgroup *memcg, int idx, unsigned long count) { - preempt_disable(); + unsigned long flags; + + local_irq_save(flags); __count_memcg_events(memcg, idx, count); - preempt_enable(); + local_irq_restore(flags); } /* idx can be of type enum memcg_event_item or vm_event_item */ -- cgit v1.2.3 From 9c4e6b1a7027f102990c0395296015a812525f4d Mon Sep 17 00:00:00 2001 From: Shakeel Butt Date: Wed, 21 Feb 2018 14:45:28 -0800 Subject: mm, mlock, vmscan: no more skipping pagevecs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When a thread mlocks an address space backed either by file pages which are currently not present in memory or swapped out anon pages (not in swapcache), a new page is allocated and added to the local pagevec (lru_add_pvec), I/O is triggered and the thread then sleeps on the page. On I/O completion, the thread can wake on a different CPU, the mlock syscall will then sets the PageMlocked() bit of the page but will not be able to put that page in unevictable LRU as the page is on the pagevec of a different CPU. Even on drain, that page will go to evictable LRU because the PageMlocked() bit is not checked on pagevec drain. The page will eventually go to right LRU on reclaim but the LRU stats will remain skewed for a long time. This patch puts all the pages, even unevictable, to the pagevecs and on the drain, the pages will be added on their LRUs correctly by checking their evictability. This resolves the mlocked pages on pagevec of other CPUs issue because when those pagevecs will be drained, the mlocked file pages will go to unevictable LRU. Also this makes the race with munlock easier to resolve because the pagevec drains happen in LRU lock. However there is still one place which makes a page evictable and does PageLRU check on that page without LRU lock and needs special attention. TestClearPageMlocked() and isolate_lru_page() in clear_page_mlock(). #0: __pagevec_lru_add_fn #1: clear_page_mlock SetPageLRU() if (!TestClearPageMlocked()) return smp_mb() // <--required // inside does PageLRU if (!PageMlocked()) if (isolate_lru_page()) move to evictable LRU putback_lru_page() else move to unevictable LRU In '#1', TestClearPageMlocked() provides full memory barrier semantics and thus the PageLRU check (inside isolate_lru_page) can not be reordered before it. In '#0', without explicit memory barrier, the PageMlocked() check can be reordered before SetPageLRU(). If that happens, '#0' can put a page in unevictable LRU and '#1' might have just cleared the Mlocked bit of that page but fails to isolate as PageLRU fails as '#0' still hasn't set PageLRU bit of that page. That page will be stranded on the unevictable LRU. There is one (good) side effect though. Without this patch, the pages allocated for System V shared memory segment are added to evictable LRUs even after shmctl(SHM_LOCK) on that segment. This patch will correctly put such pages to unevictable LRU. Link: http://lkml.kernel.org/r/20171121211241.18877-1-shakeelb@google.com Signed-off-by: Shakeel Butt Acked-by: Vlastimil Babka Cc: Jérôme Glisse Cc: Huang Ying Cc: Tim Chen Cc: Michal Hocko Cc: Greg Thelen Cc: Johannes Weiner Cc: Balbir Singh Cc: Minchan Kim Cc: Shaohua Li Cc: Jan Kara Cc: Nicholas Piggin Cc: Dan Williams Cc: Mel Gorman Cc: Hugh Dickins Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/swap.h | 2 -- mm/mlock.c | 6 ++++ mm/swap.c | 82 ++++++++++++++++++++++++++++++---------------------- mm/vmscan.c | 59 +------------------------------------ 4 files changed, 54 insertions(+), 95 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index 7b6a59f722a3..a1a3f4ed94ce 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -337,8 +337,6 @@ extern void deactivate_file_page(struct page *page); extern void mark_page_lazyfree(struct page *page); extern void swap_setup(void); -extern void add_page_to_unevictable_list(struct page *page); - extern void lru_cache_add_active_or_unevictable(struct page *page, struct vm_area_struct *vma); diff --git a/mm/mlock.c b/mm/mlock.c index 79398200e423..74e5a6547c3d 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -64,6 +64,12 @@ void clear_page_mlock(struct page *page) mod_zone_page_state(page_zone(page), NR_MLOCK, -hpage_nr_pages(page)); count_vm_event(UNEVICTABLE_PGCLEARED); + /* + * The previous TestClearPageMlocked() corresponds to the smp_mb() + * in __pagevec_lru_add_fn(). + * + * See __pagevec_lru_add_fn for more explanation. + */ if (!isolate_lru_page(page)) { putback_lru_page(page); } else { diff --git a/mm/swap.c b/mm/swap.c index 567a7b96e41d..2d337710218f 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -445,30 +445,6 @@ void lru_cache_add(struct page *page) __lru_cache_add(page); } -/** - * add_page_to_unevictable_list - add a page to the unevictable list - * @page: the page to be added to the unevictable list - * - * Add page directly to its zone's unevictable list. To avoid races with - * tasks that might be making the page evictable, through eg. munlock, - * munmap or exit, while it's not on the lru, we want to add the page - * while it's locked or otherwise "invisible" to other tasks. This is - * difficult to do when using the pagevec cache, so bypass that. - */ -void add_page_to_unevictable_list(struct page *page) -{ - struct pglist_data *pgdat = page_pgdat(page); - struct lruvec *lruvec; - - spin_lock_irq(&pgdat->lru_lock); - lruvec = mem_cgroup_page_lruvec(page, pgdat); - ClearPageActive(page); - SetPageUnevictable(page); - SetPageLRU(page); - add_page_to_lru_list(page, lruvec, LRU_UNEVICTABLE); - spin_unlock_irq(&pgdat->lru_lock); -} - /** * lru_cache_add_active_or_unevictable * @page: the page to be added to LRU @@ -484,13 +460,9 @@ void lru_cache_add_active_or_unevictable(struct page *page, { VM_BUG_ON_PAGE(PageLRU(page), page); - if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED)) { + if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED)) SetPageActive(page); - lru_cache_add(page); - return; - } - - if (!TestSetPageMlocked(page)) { + else if (!TestSetPageMlocked(page)) { /* * We use the irq-unsafe __mod_zone_page_stat because this * counter is not modified from interrupt context, and the pte @@ -500,7 +472,7 @@ void lru_cache_add_active_or_unevictable(struct page *page, hpage_nr_pages(page)); count_vm_event(UNEVICTABLE_PGMLOCKED); } - add_page_to_unevictable_list(page); + lru_cache_add(page); } /* @@ -886,15 +858,55 @@ void lru_add_page_tail(struct page *page, struct page *page_tail, static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec, void *arg) { - int file = page_is_file_cache(page); - int active = PageActive(page); - enum lru_list lru = page_lru(page); + enum lru_list lru; + int was_unevictable = TestClearPageUnevictable(page); VM_BUG_ON_PAGE(PageLRU(page), page); SetPageLRU(page); + /* + * Page becomes evictable in two ways: + * 1) Within LRU lock [munlock_vma_pages() and __munlock_pagevec()]. + * 2) Before acquiring LRU lock to put the page to correct LRU and then + * a) do PageLRU check with lock [check_move_unevictable_pages] + * b) do PageLRU check before lock [clear_page_mlock] + * + * (1) & (2a) are ok as LRU lock will serialize them. For (2b), we need + * following strict ordering: + * + * #0: __pagevec_lru_add_fn #1: clear_page_mlock + * + * SetPageLRU() TestClearPageMlocked() + * smp_mb() // explicit ordering // above provides strict + * // ordering + * PageMlocked() PageLRU() + * + * + * if '#1' does not observe setting of PG_lru by '#0' and fails + * isolation, the explicit barrier will make sure that page_evictable + * check will put the page in correct LRU. Without smp_mb(), SetPageLRU + * can be reordered after PageMlocked check and can make '#1' to fail + * the isolation of the page whose Mlocked bit is cleared (#0 is also + * looking at the same page) and the evictable page will be stranded + * in an unevictable LRU. + */ + smp_mb(); + + if (page_evictable(page)) { + lru = page_lru(page); + update_page_reclaim_stat(lruvec, page_is_file_cache(page), + PageActive(page)); + if (was_unevictable) + count_vm_event(UNEVICTABLE_PGRESCUED); + } else { + lru = LRU_UNEVICTABLE; + ClearPageActive(page); + SetPageUnevictable(page); + if (!was_unevictable) + count_vm_event(UNEVICTABLE_PGCULLED); + } + add_page_to_lru_list(page, lruvec, lru); - update_page_reclaim_stat(lruvec, file, active); trace_mm_lru_insertion(page, lru); } diff --git a/mm/vmscan.c b/mm/vmscan.c index 444749669187..bee53495a829 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -769,64 +769,7 @@ int remove_mapping(struct address_space *mapping, struct page *page) */ void putback_lru_page(struct page *page) { - bool is_unevictable; - int was_unevictable = PageUnevictable(page); - - VM_BUG_ON_PAGE(PageLRU(page), page); - -redo: - ClearPageUnevictable(page); - - if (page_evictable(page)) { - /* - * For evictable pages, we can use the cache. - * In event of a race, worst case is we end up with an - * unevictable page on [in]active list. - * We know how to handle that. - */ - is_unevictable = false; - lru_cache_add(page); - } else { - /* - * Put unevictable pages directly on zone's unevictable - * list. - */ - is_unevictable = true; - add_page_to_unevictable_list(page); - /* - * When racing with an mlock or AS_UNEVICTABLE clearing - * (page is unlocked) make sure that if the other thread - * does not observe our setting of PG_lru and fails - * isolation/check_move_unevictable_pages, - * we see PG_mlocked/AS_UNEVICTABLE cleared below and move - * the page back to the evictable list. - * - * The other side is TestClearPageMlocked() or shmem_lock(). - */ - smp_mb(); - } - - /* - * page's status can change while we move it among lru. If an evictable - * page is on unevictable list, it never be freed. To avoid that, - * check after we added it to the list, again. - */ - if (is_unevictable && page_evictable(page)) { - if (!isolate_lru_page(page)) { - put_page(page); - goto redo; - } - /* This means someone else dropped this page from LRU - * So, it will be freed or putback to LRU again. There is - * nothing to do here. - */ - } - - if (was_unevictable && !is_unevictable) - count_vm_event(UNEVICTABLE_PGRESCUED); - else if (!was_unevictable && is_unevictable) - count_vm_event(UNEVICTABLE_PGCULLED); - + lru_cache_add(page); put_page(page); /* drop ref from isolate */ } -- cgit v1.2.3 From 88913bd8ea2a75d7e460a4bed5f75e1c32660d7e Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Wed, 21 Feb 2018 14:45:32 -0800 Subject: kernel/relay.c: limit kmalloc size to KMALLOC_MAX_SIZE chan->n_subbufs is set by the user and relay_create_buf() does a kmalloc() of chan->n_subbufs * sizeof(size_t *). kmalloc_slab() will generate a warning when this fails if chan->subbufs * sizeof(size_t *) > KMALLOC_MAX_SIZE. Limit chan->n_subbufs to the maximum allowed kmalloc() size. Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1802061216100.122576@chino.kir.corp.google.com Fixes: f6302f1bcd75 ("relay: prevent integer overflow in relay_open()") Signed-off-by: David Rientjes Reviewed-by: Andrew Morton Cc: Jens Axboe Cc: Dave Jiang Cc: Al Viro Cc: Dan Carpenter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/relay.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/relay.c b/kernel/relay.c index c3029402f15c..c955b10c973c 100644 --- a/kernel/relay.c +++ b/kernel/relay.c @@ -163,7 +163,7 @@ static struct rchan_buf *relay_create_buf(struct rchan *chan) { struct rchan_buf *buf; - if (chan->n_subbufs > UINT_MAX / sizeof(size_t *)) + if (chan->n_subbufs > KMALLOC_MAX_SIZE / sizeof(size_t *)) return NULL; buf = kzalloc(sizeof(struct rchan_buf), GFP_KERNEL); -- cgit v1.2.3 From 2be04df5668d81f9a98e57b81bc53f72bd5f4f92 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Wed, 21 Feb 2018 14:45:35 -0800 Subject: certs/blacklist_nohashes.c: fix const confusion in certs blacklist const must be marked __initconst, not __initdata. Link: http://lkml.kernel.org/r/20171222001335.1987-1-andi@firstfloor.org Signed-off-by: Andi Kleen Reviewed-by: Andrew Morton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- certs/blacklist_nohashes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/certs/blacklist_nohashes.c b/certs/blacklist_nohashes.c index 73fd99098ad7..753b703ef0ef 100644 --- a/certs/blacklist_nohashes.c +++ b/certs/blacklist_nohashes.c @@ -1,6 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 #include "blacklist.h" -const char __initdata *const blacklist_hashes[] = { +const char __initconst *const blacklist_hashes[] = { NULL }; -- cgit v1.2.3 From 7ba716698cc53f8d5367766c93c538c7da6c68ce Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Wed, 21 Feb 2018 14:45:39 -0800 Subject: mm, swap, frontswap: fix THP swap if frontswap enabled It was reported by Sergey Senozhatsky that if THP (Transparent Huge Page) and frontswap (via zswap) are both enabled, when memory goes low so that swap is triggered, segfault and memory corruption will occur in random user space applications as follow, kernel: urxvt[338]: segfault at 20 ip 00007fc08889ae0d sp 00007ffc73a7fc40 error 6 in libc-2.26.so[7fc08881a000+1ae000] #0 0x00007fc08889ae0d _int_malloc (libc.so.6) #1 0x00007fc08889c2f3 malloc (libc.so.6) #2 0x0000560e6004bff7 _Z14rxvt_wcstoutf8PKwi (urxvt) #3 0x0000560e6005e75c n/a (urxvt) #4 0x0000560e6007d9f1 _ZN16rxvt_perl_interp6invokeEP9rxvt_term9hook_typez (urxvt) #5 0x0000560e6003d988 _ZN9rxvt_term9cmd_parseEv (urxvt) #6 0x0000560e60042804 _ZN9rxvt_term6pty_cbERN2ev2ioEi (urxvt) #7 0x0000560e6005c10f _Z17ev_invoke_pendingv (urxvt) #8 0x0000560e6005cb55 ev_run (urxvt) #9 0x0000560e6003b9b9 main (urxvt) #10 0x00007fc08883af4a __libc_start_main (libc.so.6) #11 0x0000560e6003f9da _start (urxvt) After bisection, it was found the first bad commit is bd4c82c22c36 ("mm, THP, swap: delay splitting THP after swapped out"). The root cause is as follows: When the pages are written to swap device during swapping out in swap_writepage(), zswap (fontswap) is tried to compress the pages to improve performance. But zswap (frontswap) will treat THP as a normal page, so only the head page is saved. After swapping in, tail pages will not be restored to their original contents, causing memory corruption in the applications. This is fixed by refusing to save page in the frontswap store functions if the page is a THP. So that the THP will be swapped out to swap device. Another choice is to split THP if frontswap is enabled. But it is found that the frontswap enabling isn't flexible. For example, if CONFIG_ZSWAP=y (cannot be module), frontswap will be enabled even if zswap itself isn't enabled. Frontswap has multiple backends, to make it easy for one backend to enable THP support, the THP checking is put in backend frontswap store functions instead of the general interfaces. Link: http://lkml.kernel.org/r/20180209084947.22749-1-ying.huang@intel.com Fixes: bd4c82c22c367e068 ("mm, THP, swap: delay splitting THP after swapped out") Signed-off-by: "Huang, Ying" Reported-by: Sergey Senozhatsky Tested-by: Sergey Senozhatsky Suggested-by: Minchan Kim [put THP checking in backend] Cc: Konrad Rzeszutek Wilk Cc: Dan Streetman Cc: Seth Jennings Cc: Tetsuo Handa Cc: Shaohua Li Cc: Michal Hocko Cc: Johannes Weiner Cc: Mel Gorman Cc: Shakeel Butt Cc: Boris Ostrovsky Cc: Juergen Gross Cc: [4.14] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/xen/tmem.c | 4 ++++ mm/zswap.c | 6 ++++++ 2 files changed, 10 insertions(+) diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c index bf13d1ec51f3..04e7b3b29bac 100644 --- a/drivers/xen/tmem.c +++ b/drivers/xen/tmem.c @@ -284,6 +284,10 @@ static int tmem_frontswap_store(unsigned type, pgoff_t offset, int pool = tmem_frontswap_poolid; int ret; + /* THP isn't supported */ + if (PageTransHuge(page)) + return -1; + if (pool < 0) return -1; if (ind64 != ind) diff --git a/mm/zswap.c b/mm/zswap.c index c004aa4fd3f4..61a5c41972db 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -1007,6 +1007,12 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset, u8 *src, *dst; struct zswap_header zhdr = { .swpentry = swp_entry(type, offset) }; + /* THP isn't supported */ + if (PageTransHuge(page)) { + ret = -EINVAL; + goto reject; + } + if (!zswap_enabled || !tree) { ret = -ENODEV; goto reject; -- cgit v1.2.3 From b1a8a7a70043400d1e685899548c92b92f640d71 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Wed, 21 Feb 2018 14:45:43 -0800 Subject: ida: do zeroing in ida_pre_get() As far as I can tell, the only place the per-cpu ida_bitmap is populated is in ida_pre_get. The pre-allocated element is stolen in two places in ida_get_new_above, in both cases immediately followed by a memset(0). Since ida_get_new_above is called with locks held, do the zeroing in ida_pre_get, or rather let kmalloc() do it. Also, apparently gcc generates ~44 bytes of code to do a memset(, 0, 128): $ scripts/bloat-o-meter vmlinux.{0,1} add/remove: 0/0 grow/shrink: 2/1 up/down: 5/-88 (-83) Function old new delta ida_pre_get 115 119 +4 vermagic 27 28 +1 ida_get_new_above 715 627 -88 Link: http://lkml.kernel.org/r/20180108225634.15340-1-linux@rasmusvillemoes.dk Signed-off-by: Rasmus Villemoes Acked-by: Matthew Wilcox Cc: Eric Biggers Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/idr.c | 2 -- lib/radix-tree.c | 2 +- 2 files changed, 1 insertion(+), 3 deletions(-) diff --git a/lib/idr.c b/lib/idr.c index c98d77fcf393..99ec5bc89d25 100644 --- a/lib/idr.c +++ b/lib/idr.c @@ -431,7 +431,6 @@ int ida_get_new_above(struct ida *ida, int start, int *id) bitmap = this_cpu_xchg(ida_bitmap, NULL); if (!bitmap) return -EAGAIN; - memset(bitmap, 0, sizeof(*bitmap)); bitmap->bitmap[0] = tmp >> RADIX_TREE_EXCEPTIONAL_SHIFT; rcu_assign_pointer(*slot, bitmap); } @@ -464,7 +463,6 @@ int ida_get_new_above(struct ida *ida, int start, int *id) bitmap = this_cpu_xchg(ida_bitmap, NULL); if (!bitmap) return -EAGAIN; - memset(bitmap, 0, sizeof(*bitmap)); __set_bit(bit, bitmap->bitmap); radix_tree_iter_replace(root, &iter, slot, bitmap); } diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 0a7ae3288a24..8e00138d593f 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -2125,7 +2125,7 @@ int ida_pre_get(struct ida *ida, gfp_t gfp) preempt_enable(); if (!this_cpu_read(ida_bitmap)) { - struct ida_bitmap *bitmap = kmalloc(sizeof(*bitmap), gfp); + struct ida_bitmap *bitmap = kzalloc(sizeof(*bitmap), gfp); if (!bitmap) return 0; if (this_cpu_cmpxchg(ida_bitmap, NULL, bitmap)) -- cgit v1.2.3 From 14fec9eba43b05d39825128e4354a2dc50fb59ea Mon Sep 17 00:00:00 2001 From: Mike Rapoport Date: Wed, 21 Feb 2018 14:45:46 -0800 Subject: mm/zpool.c: zpool_evictable: fix mismatch in parameter name and kernel-doc [akpm@linux-foundation.org: add colon, per Randy] Link: http://lkml.kernel.org/r/1518116984-21141-1-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport Reviewed-by: Andrew Morton Cc: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/zpool.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/zpool.c b/mm/zpool.c index f8cb83e7699b..01a771e304fa 100644 --- a/mm/zpool.c +++ b/mm/zpool.c @@ -360,7 +360,7 @@ u64 zpool_get_total_size(struct zpool *zpool) /** * zpool_evictable() - Test if zpool is potentially evictable - * @pool The zpool to test + * @zpool: The zpool to test * * Zpool is only potentially evictable when it's created with struct * zpool_ops.evict and its driver implements struct zpool_driver.shrink. -- cgit v1.2.3 From cb6f0f34802dd7148d930f4f8d1cce991b8c23be Mon Sep 17 00:00:00 2001 From: Mike Rapoport Date: Wed, 21 Feb 2018 14:45:50 -0800 Subject: mm/swap.c: make functions and their kernel-doc agree (again) There was a conflict between the commit e02a9f048ef7 ("mm/swap.c: make functions and their kernel-doc agree") and the commit f144c390f905 ("mm: docs: fix parameter names mismatch") that both tried to fix mismatch betweeen pagevec_lookup_entries() parameter names and their description. Since nr_entries is a better name for the parameter, fix the description again. Link: http://lkml.kernel.org/r/1518116946-20947-1-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport Acked-by: Randy Dunlap Reviewed-by: Andrew Morton Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/swap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/swap.c b/mm/swap.c index 2d337710218f..0f17330dd0e5 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -925,7 +925,7 @@ EXPORT_SYMBOL(__pagevec_lru_add); * @pvec: Where the resulting entries are placed * @mapping: The address_space to search * @start: The starting entry index - * @nr_pages: The maximum number of pages + * @nr_entries: The maximum number of pages * @indices: The cache indices corresponding to the entries in @pvec * * pagevec_lookup_entries() will search for and return a group of up -- cgit v1.2.3 From 173a3efd3edb2ef6ef07471397c5f542a360e9c1 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 21 Feb 2018 14:45:54 -0800 Subject: bug.h: work around GCC PR82365 in BUG() Looking at functions with large stack frames across all architectures led me discovering that BUG() suffers from the same problem as fortify_panic(), which I've added a workaround for already. In short, variables that go out of scope by calling a noreturn function or __builtin_unreachable() keep using stack space in functions afterwards. A workaround that was identified is to insert an empty assembler statement just before calling the function that doesn't return. I'm adding a macro "barrier_before_unreachable()" to document this, and insert calls to that in all instances of BUG() that currently suffer from this problem. The files that saw the largest change from this had these frame sizes before, and much less with my patch: fs/ext4/inode.c:82:1: warning: the frame size of 1672 bytes is larger than 800 bytes [-Wframe-larger-than=] fs/ext4/namei.c:434:1: warning: the frame size of 904 bytes is larger than 800 bytes [-Wframe-larger-than=] fs/ext4/super.c:2279:1: warning: the frame size of 1160 bytes is larger than 800 bytes [-Wframe-larger-than=] fs/ext4/xattr.c:146:1: warning: the frame size of 1168 bytes is larger than 800 bytes [-Wframe-larger-than=] fs/f2fs/inode.c:152:1: warning: the frame size of 1424 bytes is larger than 800 bytes [-Wframe-larger-than=] net/netfilter/ipvs/ip_vs_core.c:1195:1: warning: the frame size of 1068 bytes is larger than 800 bytes [-Wframe-larger-than=] net/netfilter/ipvs/ip_vs_core.c:395:1: warning: the frame size of 1084 bytes is larger than 800 bytes [-Wframe-larger-than=] net/netfilter/ipvs/ip_vs_ftp.c:298:1: warning: the frame size of 928 bytes is larger than 800 bytes [-Wframe-larger-than=] net/netfilter/ipvs/ip_vs_ftp.c:418:1: warning: the frame size of 908 bytes is larger than 800 bytes [-Wframe-larger-than=] net/netfilter/ipvs/ip_vs_lblcr.c:718:1: warning: the frame size of 960 bytes is larger than 800 bytes [-Wframe-larger-than=] drivers/net/xen-netback/netback.c:1500:1: warning: the frame size of 1088 bytes is larger than 800 bytes [-Wframe-larger-than=] In case of ARC and CRIS, it turns out that the BUG() implementation actually does return (or at least the compiler thinks it does), resulting in lots of warnings about uninitialized variable use and leaving noreturn functions, such as: block/cfq-iosched.c: In function 'cfq_async_queue_prio': block/cfq-iosched.c:3804:1: error: control reaches end of non-void function [-Werror=return-type] include/linux/dmaengine.h: In function 'dma_maxpq': include/linux/dmaengine.h:1123:1: error: control reaches end of non-void function [-Werror=return-type] This makes them call __builtin_trap() instead, which should normally dump the stack and kill the current process, like some of the other architectures already do. I tried adding barrier_before_unreachable() to panic() and fortify_panic() as well, but that had very little effect, so I'm not submitting that patch. Vineet said: : For ARC, it is double win. : : 1. Fixes 3 -Wreturn-type warnings : : | ../net/core/ethtool.c:311:1: warning: control reaches end of non-void function : [-Wreturn-type] : | ../kernel/sched/core.c:3246:1: warning: control reaches end of non-void function : [-Wreturn-type] : | ../include/linux/sunrpc/svc_xprt.h:180:1: warning: control reaches end of : non-void function [-Wreturn-type] : : 2. bloat-o-meter reports code size improvements as gcc elides the : generated code for stack return. Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365 Link: http://lkml.kernel.org/r/20171219114112.939391-1-arnd@arndb.de Signed-off-by: Arnd Bergmann Acked-by: Vineet Gupta [arch/arc] Tested-by: Vineet Gupta [arch/arc] Cc: Mikael Starvik Cc: Jesper Nilsson Cc: Tony Luck Cc: Fenghua Yu Cc: Geert Uytterhoeven Cc: "David S. Miller" Cc: Christopher Li Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Kees Cook Cc: Ingo Molnar Cc: Josh Poimboeuf Cc: Will Deacon Cc: "Steven Rostedt (VMware)" Cc: Mark Rutland Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/arc/include/asm/bug.h | 3 ++- arch/cris/include/arch-v10/arch/bug.h | 11 +++++++++-- arch/ia64/include/asm/bug.h | 6 +++++- arch/m68k/include/asm/bug.h | 3 +++ arch/sparc/include/asm/bug.h | 6 +++++- include/asm-generic/bug.h | 1 + include/linux/compiler-gcc.h | 15 ++++++++++++++- include/linux/compiler.h | 5 +++++ 8 files changed, 44 insertions(+), 6 deletions(-) diff --git a/arch/arc/include/asm/bug.h b/arch/arc/include/asm/bug.h index ea022d47896c..21ec82466d62 100644 --- a/arch/arc/include/asm/bug.h +++ b/arch/arc/include/asm/bug.h @@ -23,7 +23,8 @@ void die(const char *str, struct pt_regs *regs, unsigned long address); #define BUG() do { \ pr_warn("BUG: failure at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \ - dump_stack(); \ + barrier_before_unreachable(); \ + __builtin_trap(); \ } while (0) #define HAVE_ARCH_BUG diff --git a/arch/cris/include/arch-v10/arch/bug.h b/arch/cris/include/arch-v10/arch/bug.h index 905afeacfedf..06da9d49152a 100644 --- a/arch/cris/include/arch-v10/arch/bug.h +++ b/arch/cris/include/arch-v10/arch/bug.h @@ -44,18 +44,25 @@ struct bug_frame { * not be used like this with newer versions of gcc. */ #define BUG() \ +do { \ __asm__ __volatile__ ("clear.d [" __stringify(BUG_MAGIC) "]\n\t"\ "movu.w " __stringify(__LINE__) ",$r0\n\t"\ "jump 0f\n\t" \ ".section .rodata\n" \ "0:\t.string \"" __FILE__ "\"\n\t" \ - ".previous") + ".previous"); \ + unreachable(); \ +} while (0) #endif #else /* This just causes an oops. */ -#define BUG() (*(int *)0 = 0) +#define BUG() \ +do { \ + barrier_before_unreachable(); \ + __builtin_trap(); \ +} while (0) #endif diff --git a/arch/ia64/include/asm/bug.h b/arch/ia64/include/asm/bug.h index bd3eeb8d1cfa..66b37a532765 100644 --- a/arch/ia64/include/asm/bug.h +++ b/arch/ia64/include/asm/bug.h @@ -4,7 +4,11 @@ #ifdef CONFIG_BUG #define ia64_abort() __builtin_trap() -#define BUG() do { printk("kernel BUG at %s:%d!\n", __FILE__, __LINE__); ia64_abort(); } while (0) +#define BUG() do { \ + printk("kernel BUG at %s:%d!\n", __FILE__, __LINE__); \ + barrier_before_unreachable(); \ + ia64_abort(); \ +} while (0) /* should this BUG be made generic? */ #define HAVE_ARCH_BUG diff --git a/arch/m68k/include/asm/bug.h b/arch/m68k/include/asm/bug.h index b7e2bf1ba4a6..275dca1435bf 100644 --- a/arch/m68k/include/asm/bug.h +++ b/arch/m68k/include/asm/bug.h @@ -8,16 +8,19 @@ #ifndef CONFIG_SUN3 #define BUG() do { \ pr_crit("kernel BUG at %s:%d!\n", __FILE__, __LINE__); \ + barrier_before_unreachable(); \ __builtin_trap(); \ } while (0) #else #define BUG() do { \ pr_crit("kernel BUG at %s:%d!\n", __FILE__, __LINE__); \ + barrier_before_unreachable(); \ panic("BUG!"); \ } while (0) #endif #else #define BUG() do { \ + barrier_before_unreachable(); \ __builtin_trap(); \ } while (0) #endif diff --git a/arch/sparc/include/asm/bug.h b/arch/sparc/include/asm/bug.h index 6f17528356b2..ea53e418f6c0 100644 --- a/arch/sparc/include/asm/bug.h +++ b/arch/sparc/include/asm/bug.h @@ -9,10 +9,14 @@ void do_BUG(const char *file, int line); #define BUG() do { \ do_BUG(__FILE__, __LINE__); \ + barrier_before_unreachable(); \ __builtin_trap(); \ } while (0) #else -#define BUG() __builtin_trap() +#define BUG() do { \ + barrier_before_unreachable(); \ + __builtin_trap(); \ +} while (0) #endif #define HAVE_ARCH_BUG diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h index 963b755d19b0..a7613e1b0c87 100644 --- a/include/asm-generic/bug.h +++ b/include/asm-generic/bug.h @@ -52,6 +52,7 @@ struct bug_entry { #ifndef HAVE_ARCH_BUG #define BUG() do { \ printk("BUG: failure at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \ + barrier_before_unreachable(); \ panic("BUG!"); \ } while (0) #endif diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 73bc63e0a1c4..901c1ccb3374 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -207,6 +207,15 @@ #endif #endif +/* + * calling noreturn functions, __builtin_unreachable() and __builtin_trap() + * confuse the stack allocation in gcc, leading to overly large stack + * frames, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365 + * + * Adding an empty inline assembly before it works around the problem + */ +#define barrier_before_unreachable() asm volatile("") + /* * Mark a position in code as unreachable. This can be used to * suppress control flow warnings after asm blocks that transfer @@ -217,7 +226,11 @@ * unreleased. Really, we need to have autoconf for the kernel. */ #define unreachable() \ - do { annotate_unreachable(); __builtin_unreachable(); } while (0) + do { \ + annotate_unreachable(); \ + barrier_before_unreachable(); \ + __builtin_unreachable(); \ + } while (0) /* Mark a function definition as prohibited from being cloned. */ #define __noclone __attribute__((__noclone__, __optimize__("no-tracer"))) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index e835fc0423ec..ab4711c63601 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -86,6 +86,11 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, # define barrier_data(ptr) barrier() #endif +/* workaround for GCC PR82365 if needed */ +#ifndef barrier_before_unreachable +# define barrier_before_unreachable() do { } while (0) +#endif + /* Unreachable code */ #ifdef CONFIG_STACK_VALIDATION /* -- cgit v1.2.3 From bdefe01a6b14bde268741435ac854fda4ef7e847 Mon Sep 17 00:00:00 2001 From: Anders Roxell Date: Wed, 21 Feb 2018 14:45:58 -0800 Subject: selftests/memfd: add run_fuse_test.sh to TEST_FILES MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit While testing memfd tests, there is a missing script, as reported by kselftest: ./run_tests.sh: line 7: ./run_fuse_test.sh: No such file or directory Link: http://lkml.kernel.org/r/1517955779-11386-1-git-send-email-daniel.diaz@linaro.org Signed-off-by: Anders Roxell Signed-off-by: Daniel Díaz Cc: Shuah Khan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- tools/testing/selftests/memfd/Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/memfd/Makefile b/tools/testing/selftests/memfd/Makefile index a5276a91dfbf..0862e6f47a38 100644 --- a/tools/testing/selftests/memfd/Makefile +++ b/tools/testing/selftests/memfd/Makefile @@ -5,6 +5,7 @@ CFLAGS += -I../../../../include/ CFLAGS += -I../../../../usr/include/ TEST_PROGS := run_tests.sh +TEST_FILES := run_fuse_test.sh TEST_GEN_FILES := memfd_test fuse_mnt fuse_test fuse_mnt.o: CFLAGS += $(shell pkg-config fuse --cflags) -- cgit v1.2.3 From 698d0831ba87b92ae10b15e8203cfd59f5a59a35 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Wed, 21 Feb 2018 14:46:01 -0800 Subject: vmalloc: fix __GFP_HIGHMEM usage for vmalloc_32 on 32b systems MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Kai Heng Feng has noticed that BUG_ON(PageHighMem(pg)) triggers in drivers/media/common/saa7146/saa7146_core.c since 19809c2da28a ("mm, vmalloc: use __GFP_HIGHMEM implicitly"). saa7146_vmalloc_build_pgtable uses vmalloc_32 and it is reasonable to expect that the resulting page is not in highmem. The above commit aimed to add __GFP_HIGHMEM only for those requests which do not specify any zone modifier gfp flag. vmalloc_32 relies on GFP_VMALLOC32 which should do the right thing. Except it has been missed that GFP_VMALLOC32 is an alias for GFP_KERNEL on 32b architectures. Thanks to Matthew to notice this. Fix the problem by unconditionally setting GFP_DMA32 in GFP_VMALLOC32 for !64b arches (as a bailout). This should do the right thing and use ZONE_NORMAL which should be always below 4G on 32b systems. Debugged by Matthew Wilcox. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20180212095019.GX21609@dhcp22.suse.cz Fixes: 19809c2da28a ("mm, vmalloc: use __GFP_HIGHMEM implicitly”) Signed-off-by: Michal Hocko Reported-by: Kai Heng Feng Cc: Matthew Wilcox Cc: Laura Abbott Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmalloc.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 673942094328..ebff729cc956 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1943,11 +1943,15 @@ void *vmalloc_exec(unsigned long size) } #if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32) -#define GFP_VMALLOC32 GFP_DMA32 | GFP_KERNEL +#define GFP_VMALLOC32 (GFP_DMA32 | GFP_KERNEL) #elif defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA) -#define GFP_VMALLOC32 GFP_DMA | GFP_KERNEL +#define GFP_VMALLOC32 (GFP_DMA | GFP_KERNEL) #else -#define GFP_VMALLOC32 GFP_KERNEL +/* + * 64b systems should always have either DMA or DMA32 zones. For others + * GFP_DMA32 should do the right thing and use the normal zone. + */ +#define GFP_VMALLOC32 GFP_DMA32 | GFP_KERNEL #endif /** -- cgit v1.2.3 From 908009e832b4e58796ed95d4544e3210bc0ff2c4 Mon Sep 17 00:00:00 2001 From: Anders Roxell Date: Wed, 21 Feb 2018 14:46:05 -0800 Subject: lib/Kconfig.debug: enable RUNTIME_TESTING_MENU Commit d3deafaa8b5c ("lib/: make RUNTIME_TESTS a menuconfig to ease disabling it all") causes a regression when using runtime tests due to it defaults RUNTIME_TESTING_MENU to not set. Link: http://lkml.kernel.org/r/20180214133015.10090-1-anders.roxell@linaro.org Fixes: d3deafaa8b5c ("lib/: make RUNTIME_TESTS a menuconfig to easedisabling it all") Signed-off-by: Anders Roxell Cc: Vincent Legoll Cc: Ingo Molnar Cc: Byungchul Park Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/Kconfig.debug | 1 + 1 file changed, 1 insertion(+) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 6088408ef26c..64155e310a9f 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1642,6 +1642,7 @@ config DMA_API_DEBUG menuconfig RUNTIME_TESTING_MENU bool "Runtime Testing" + def_bool y if RUNTIME_TESTING_MENU -- cgit v1.2.3 From 895f7b8e90200cf1a5dc313329369adf30e51f9a Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Wed, 21 Feb 2018 14:46:09 -0800 Subject: mm: don't defer struct page initialization for Xen pv guests Commit f7f99100d8d9 ("mm: stop zeroing memory during allocation in vmemmap") broke Xen pv domains in some configurations, as the "Pinned" information in struct page of early page tables could get lost. This will lead to the kernel trying to write directly into the page tables instead of asking the hypervisor to do so. The result is a crash like the following: BUG: unable to handle kernel paging request at ffff8801ead19008 IP: xen_set_pud+0x4e/0xd0 PGD 1c0a067 P4D 1c0a067 PUD 23a0067 PMD 1e9de0067 PTE 80100001ead19065 Oops: 0003 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.14.0-default+ #271 Hardware name: Dell Inc. Latitude E6440/0159N7, BIOS A07 06/26/2014 task: ffffffff81c10480 task.stack: ffffffff81c00000 RIP: e030:xen_set_pud+0x4e/0xd0 Call Trace: __pmd_alloc+0x128/0x140 ioremap_page_range+0x3f4/0x410 __ioremap_caller+0x1c3/0x2e0 acpi_os_map_iomem+0x175/0x1b0 acpi_tb_acquire_table+0x39/0x66 acpi_tb_validate_table+0x44/0x7c acpi_tb_verify_temp_table+0x45/0x304 acpi_reallocate_root_table+0x12d/0x141 acpi_early_init+0x4d/0x10a start_kernel+0x3eb/0x4a1 xen_start_kernel+0x528/0x532 Code: 48 01 e8 48 0f 42 15 a2 fd be 00 48 01 d0 48 ba 00 00 00 00 00 ea ff ff 48 c1 e8 0c 48 c1 e0 06 48 01 d0 48 8b 00 f6 c4 02 75 5d <4c> 89 65 00 5b 5d 41 5c c3 65 8b 05 52 9f fe 7e 89 c0 48 0f a3 RIP: xen_set_pud+0x4e/0xd0 RSP: ffffffff81c03cd8 CR2: ffff8801ead19008 ---[ end trace 38eca2e56f1b642e ]--- Avoid this problem by not deferring struct page initialization when running as Xen pv guest. Pavel said: : This is unique for Xen, so this particular issue won't effect other : configurations. I am going to investigate if there is a way to : re-enable deferred page initialization on xen guests. [akpm@linux-foundation.org: explicitly include xen.h] Link: http://lkml.kernel.org/r/20180216154101.22865-1-jgross@suse.com Fixes: f7f99100d8d95d ("mm: stop zeroing memory during allocation in vmemmap") Signed-off-by: Juergen Gross Reviewed-by: Pavel Tatashin Cc: Steven Sistare Cc: Daniel Jordan Cc: Bob Picco Cc: [4.15.x] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 81e18ceef579..cb416723538f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -46,6 +46,7 @@ #include #include #include +#include #include #include #include @@ -347,6 +348,9 @@ static inline bool update_defer_init(pg_data_t *pgdat, /* Always populate low zones for address-constrained allocations */ if (zone_end < pgdat_end_pfn(pgdat)) return true; + /* Xen PV domains need page structures early */ + if (xen_pv_domain()) + return true; (*nr_initialised)++; if ((*nr_initialised > pgdat->static_init_pgcnt) && (pfn & (PAGES_PER_SECTION - 1)) == 0) { -- cgit v1.2.3