Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton: "10 patches. Subsystems affected by this patch series: mm (pagealloc, gup, kasan, and userfaultfd), ipc, selftests, watchdog, bitmap, procfs, and lib" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: userfaultfd: hugetlbfs: fix new flag usage in error path lib: kunit: suppress a compilation warning of frame size proc: remove Alexey from MAINTAINERS linux/bits.h: fix compilation error with GENMASK watchdog: reliable handling of timestamps kasan: slab: always reset the tag in get_freepointer_safe() tools/testing/selftests/exec: fix link error ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry Revert "mm/gup: check page posion status for coredump." mm/shuffle: fix section mismatch warning
mariux64 · May 23, 2021 · 34c5c89 · 34c5c89
2 parents 4ff2473 + e32905e
commit 34c5c89
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Showing 18 changed files with 74 additions and 75 deletions.
diff --git a/MAINTAINERS b/MAINTAINERS
@@ -14735,7 +14735,6 @@ W:	https://wireless.wiki.kernel.org/en/users/Drivers/p54
 F:	drivers/net/wireless/intersil/prism54/
 
 PROC FILESYSTEM
-R:	Alexey Dobriyan <adobriyan@gmail.com>
 L:	linux-kernel@vger.kernel.org
 L:	linux-fsdevel@vger.kernel.org
 S:	Maintained

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
@@ -529,7 +529,7 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 			 * the subpool and global reserve usage count can need
 			 * to be adjusted.
 			 */
-			VM_BUG_ON(PagePrivate(page));
+			VM_BUG_ON(HPageRestoreReserve(page));
 			remove_huge_page(page);
 			freed++;
 			if (!truncate_op) {

diff --git a/include/linux/bits.h b/include/linux/bits.h
@@ -22,7 +22,7 @@
 #include <linux/build_bug.h>
 #define GENMASK_INPUT_CHECK(h, l) \
 	(BUILD_BUG_ON_ZERO(__builtin_choose_expr( \
-		__builtin_constant_p((l) > (h)), (l) > (h), 0)))
+		__is_constexpr((l) > (h)), (l) > (h), 0)))
 #else
 /*
  * BUILD_BUG_ON_ZERO is not available in h files included from asm files,

diff --git a/include/linux/const.h b/include/linux/const.h
@@ -3,4 +3,12 @@
 
 #include <vdso/const.h>
 
+/*
+ * This returns a constant expression while determining if an argument is
+ * a constant expression, most importantly without evaluating the argument.
+ * Glory to Martin Uecker <Martin.Uecker@med.uni-goettingen.de>
+ */
+#define __is_constexpr(x) \
+	(sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
+
 #endif /* _LINUX_CONST_H */
diff --git a/include/linux/minmax.h b/include/linux/minmax.h
@@ -2,6 +2,8 @@
 #ifndef _LINUX_MINMAX_H
 #define _LINUX_MINMAX_H
 
+#include <linux/const.h>
+
 /*
  * min()/max()/clamp() macros must accomplish three things:
  *
@@ -17,14 +19,6 @@
 #define __typecheck(x, y) \
 	(!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
 
-/*
- * This returns a constant expression while determining if an argument is
- * a constant expression, most importantly without evaluating the argument.
- * Glory to Martin Uecker <Martin.Uecker@med.uni-goettingen.de>
- */
-#define __is_constexpr(x) \
-	(sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
-
 #define __no_side_effects(x, y) \
 		(__is_constexpr(x) && __is_constexpr(y))
 

diff --git a/ipc/mqueue.c b/ipc/mqueue.c
@@ -1004,12 +1004,14 @@ static inline void __pipelined_op(struct wake_q_head *wake_q,
 				  struct mqueue_inode_info *info,
 				  struct ext_wait_queue *this)
 {
+	struct task_struct *task;
+
 	list_del(&this->list);
-	get_task_struct(this->task);
+	task = get_task_struct(this->task);
 
 	/* see MQ_BARRIER for purpose/pairing */
 	smp_store_release(&this->state, STATE_READY);
-	wake_q_add_safe(wake_q, this->task);
+	wake_q_add_safe(wake_q, task);
 }
 
 /* pipelined_send() - send a message directly to the task waiting in

diff --git a/ipc/msg.c b/ipc/msg.c
@@ -251,11 +251,13 @@ static void expunge_all(struct msg_queue *msq, int res,
 	struct msg_receiver *msr, *t;
 
 	list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
-		get_task_struct(msr->r_tsk);
+		struct task_struct *r_tsk;
+
+		r_tsk = get_task_struct(msr->r_tsk);
 
 		/* see MSG_BARRIER for purpose/pairing */
 		smp_store_release(&msr->r_msg, ERR_PTR(res));
-		wake_q_add_safe(wake_q, msr->r_tsk);
+		wake_q_add_safe(wake_q, r_tsk);
 	}
 }
 

diff --git a/ipc/sem.c b/ipc/sem.c
@@ -784,12 +784,14 @@ static int perform_atomic_semop(struct sem_array *sma, struct sem_queue *q)
 static inline void wake_up_sem_queue_prepare(struct sem_queue *q, int error,
 					     struct wake_q_head *wake_q)
 {
-	get_task_struct(q->sleeper);
+	struct task_struct *sleeper;
+
+	sleeper = get_task_struct(q->sleeper);
 
 	/* see SEM_BARRIER_2 for purpose/pairing */
 	smp_store_release(&q->status, error);
 
-	wake_q_add_safe(wake_q, q->sleeper);
+	wake_q_add_safe(wake_q, sleeper);
 }
 
 static void unlink_queue(struct sem_array *sma, struct sem_queue *q)

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
@@ -302,10 +302,10 @@ void touch_softlockup_watchdog_sync(void)
 	__this_cpu_write(watchdog_report_ts, SOFTLOCKUP_DELAY_REPORT);
 }
 
-static int is_softlockup(unsigned long touch_ts, unsigned long period_ts)
+static int is_softlockup(unsigned long touch_ts,
+			 unsigned long period_ts,
+			 unsigned long now)
 {
-	unsigned long now = get_timestamp();
-
 	if ((watchdog_enabled & SOFT_WATCHDOG_ENABLED) && watchdog_thresh){
 		/* Warn about unreasonable delays. */
 		if (time_after(now, period_ts + get_softlockup_thresh()))
@@ -353,8 +353,7 @@ static int softlockup_fn(void *data)
 /* watchdog kicker functions */
 static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
 {
-	unsigned long touch_ts = __this_cpu_read(watchdog_touch_ts);
-	unsigned long period_ts = __this_cpu_read(watchdog_report_ts);
+	unsigned long touch_ts, period_ts, now;
 	struct pt_regs *regs = get_irq_regs();
 	int duration;
 	int softlockup_all_cpu_backtrace = sysctl_softlockup_all_cpu_backtrace;
@@ -376,12 +375,23 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
 	/* .. and repeat */
 	hrtimer_forward_now(hrtimer, ns_to_ktime(sample_period));
 
+	/*
+	 * Read the current timestamp first. It might become invalid anytime
+	 * when a virtual machine is stopped by the host or when the watchog
+	 * is touched from NMI.
+	 */
+	now = get_timestamp();
 	/*
 	 * If a virtual machine is stopped by the host it can look to
-	 * the watchdog like a soft lockup. Check to see if the host
-	 * stopped the vm before we process the timestamps.
+	 * the watchdog like a soft lockup. This function touches the watchdog.
 	 */
 	kvm_check_and_clear_guest_paused();
+	/*
+	 * The stored timestamp is comparable with @now only when not touched.
+	 * It might get touched anytime from NMI. Make sure that is_softlockup()
+	 * uses the same (valid) value.
+	 */
+	period_ts = READ_ONCE(*this_cpu_ptr(&watchdog_report_ts));
 
 	/* Reset the interval when touched by known problematic code. */
 	if (period_ts == SOFTLOCKUP_DELAY_REPORT) {
@@ -398,13 +408,9 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
 		return HRTIMER_RESTART;
 	}
 
-	/* check for a softlockup
-	 * This is done by making sure a high priority task is
-	 * being scheduled.  The task touches the watchdog to
-	 * indicate it is getting cpu time.  If it hasn't then
-	 * this is a good indication some task is hogging the cpu
-	 */
-	duration = is_softlockup(touch_ts, period_ts);
+	/* Check for a softlockup. */
+	touch_ts = __this_cpu_read(watchdog_touch_ts);
+	duration = is_softlockup(touch_ts, period_ts, now);
 	if (unlikely(duration)) {
 		/*
 		 * Prevent multiple soft-lockup reports if one cpu is already

diff --git a/lib/Makefile b/lib/Makefile
@@ -348,6 +348,7 @@ obj-$(CONFIG_OBJAGG) += objagg.o
 obj-$(CONFIG_PLDMFW) += pldmfw/
 
 # KUnit tests
+CFLAGS_bitfield_kunit.o := $(call cc-option,-Wframe-larger-than=10240)
 obj-$(CONFIG_BITFIELD_KUNIT) += bitfield_kunit.o
 obj-$(CONFIG_LIST_KUNIT_TEST) += list-test.o
 obj-$(CONFIG_LINEAR_RANGES_TEST) += test_linear_ranges.o

diff --git a/mm/gup.c b/mm/gup.c
@@ -1593,10 +1593,6 @@ struct page *get_dump_page(unsigned long addr)
 				      FOLL_FORCE | FOLL_DUMP | FOLL_GET);
 	if (locked)
 		mmap_read_unlock(mm);
-
-	if (ret == 1 && is_page_poisoned(page))
-		return NULL;
-
 	return (ret == 1) ? page : NULL;
 }
 #endif /* CONFIG_ELF_CORE */

diff --git a/mm/internal.h b/mm/internal.h
@@ -96,26 +96,6 @@ static inline void set_page_refcounted(struct page *page)
 	set_page_count(page, 1);
 }
 
-/*
- * When kernel touch the user page, the user page may be have been marked
- * poison but still mapped in user space, if without this page, the kernel
- * can guarantee the data integrity and operation success, the kernel is
- * better to check the posion status and avoid touching it, be good not to
- * panic, coredump for process fatal signal is a sample case matching this
- * scenario. Or if kernel can't guarantee the data integrity, it's better
- * not to call this function, let kernel touch the poison page and get to
- * panic.
- */
-static inline bool is_page_poisoned(struct page *page)
-{
-	if (PageHWPoison(page))
-		return true;
-	else if (PageHuge(page) && PageHWPoison(compound_head(page)))
-		return true;
-
-	return false;
-}
-
 extern unsigned long highest_memmap_pfn;
 
 /*

diff --git a/mm/shuffle.h b/mm/shuffle.h
@@ -10,15 +10,15 @@
 DECLARE_STATIC_KEY_FALSE(page_alloc_shuffle_key);
 extern void __shuffle_free_memory(pg_data_t *pgdat);
 extern bool shuffle_pick_tail(void);
-static inline void shuffle_free_memory(pg_data_t *pgdat)
+static inline void __meminit shuffle_free_memory(pg_data_t *pgdat)
 {
 	if (!static_branch_unlikely(&page_alloc_shuffle_key))
 		return;
 	__shuffle_free_memory(pgdat);
 }
 
 extern void __shuffle_zone(struct zone *z);
-static inline void shuffle_zone(struct zone *z)
+static inline void __meminit shuffle_zone(struct zone *z)
 {
 	if (!static_branch_unlikely(&page_alloc_shuffle_key))
 		return;

diff --git a/mm/slub.c b/mm/slub.c
@@ -301,6 +301,7 @@ static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
 	if (!debug_pagealloc_enabled_static())
 		return get_freepointer(s, object);
 
+	object = kasan_reset_tag(object);
 	freepointer_addr = (unsigned long)object + s->offset;
 	copy_from_kernel_nofault(&p, (void **)freepointer_addr, sizeof(p));
 	return freelist_ptr(s, p, freepointer_addr);

diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
@@ -360,38 +360,38 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm,
 		 * If a reservation for the page existed in the reservation
 		 * map of a private mapping, the map was modified to indicate
 		 * the reservation was consumed when the page was allocated.
-		 * We clear the PagePrivate flag now so that the global
+		 * We clear the HPageRestoreReserve flag now so that the global
 		 * reserve count will not be incremented in free_huge_page.
 		 * The reservation map will still indicate the reservation
 		 * was consumed and possibly prevent later page allocation.
 		 * This is better than leaking a global reservation.  If no
-		 * reservation existed, it is still safe to clear PagePrivate
-		 * as no adjustments to reservation counts were made during
-		 * allocation.
+		 * reservation existed, it is still safe to clear
+		 * HPageRestoreReserve as no adjustments to reservation counts
+		 * were made during allocation.
 		 *
 		 * The reservation map for shared mappings indicates which
 		 * pages have reservations.  When a huge page is allocated
 		 * for an address with a reservation, no change is made to
-		 * the reserve map.  In this case PagePrivate will be set
-		 * to indicate that the global reservation count should be
+		 * the reserve map.  In this case HPageRestoreReserve will be
+		 * set to indicate that the global reservation count should be
 		 * incremented when the page is freed.  This is the desired
 		 * behavior.  However, when a huge page is allocated for an
 		 * address without a reservation a reservation entry is added
-		 * to the reservation map, and PagePrivate will not be set.
-		 * When the page is freed, the global reserve count will NOT
-		 * be incremented and it will appear as though we have leaked
-		 * reserved page.  In this case, set PagePrivate so that the
-		 * global reserve count will be incremented to match the
-		 * reservation map entry which was created.
+		 * to the reservation map, and HPageRestoreReserve will not be
+		 * set. When the page is freed, the global reserve count will
+		 * NOT be incremented and it will appear as though we have
+		 * leaked reserved page.  In this case, set HPageRestoreReserve
+		 * so that the global reserve count will be incremented to
+		 * match the reservation map entry which was created.
 		 *
 		 * Note that vm_alloc_shared is based on the flags of the vma
 		 * for which the page was originally allocated.  dst_vma could
 		 * be different or NULL on error.
 		 */
 		if (vm_alloc_shared)
-			SetPagePrivate(page);
+			SetHPageRestoreReserve(page);
 		else
-			ClearPagePrivate(page);
+			ClearHPageRestoreReserve(page);
 		put_page(page);
 	}
 	BUG_ON(copied < 0);

diff --git a/tools/include/linux/bits.h b/tools/include/linux/bits.h
@@ -22,7 +22,7 @@
 #include <linux/build_bug.h>
 #define GENMASK_INPUT_CHECK(h, l) \
 	(BUILD_BUG_ON_ZERO(__builtin_choose_expr( \
-		__builtin_constant_p((l) > (h)), (l) > (h), 0)))
+		__is_constexpr((l) > (h)), (l) > (h), 0)))
 #else
 /*
  * BUILD_BUG_ON_ZERO is not available in h files included from asm files,

diff --git a/tools/include/linux/const.h b/tools/include/linux/const.h
@@ -3,4 +3,12 @@
 
 #include <vdso/const.h>
 
+/*
+ * This returns a constant expression while determining if an argument is
+ * a constant expression, most importantly without evaluating the argument.
+ * Glory to Martin Uecker <Martin.Uecker@med.uni-goettingen.de>
+ */
+#define __is_constexpr(x) \
+	(sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
+
 #endif /* _LINUX_CONST_H */
diff --git a/tools/testing/selftests/exec/Makefile b/tools/testing/selftests/exec/Makefile
@@ -28,8 +28,8 @@ $(OUTPUT)/execveat.denatured: $(OUTPUT)/execveat
 	cp $< $@
 	chmod -x $@
 $(OUTPUT)/load_address_4096: load_address.c
-	$(CC) $(CFLAGS) $(LDFLAGS) -Wl,-z,max-page-size=0x1000 -pie $< -o $@
+	$(CC) $(CFLAGS) $(LDFLAGS) -Wl,-z,max-page-size=0x1000 -pie -static $< -o $@
 $(OUTPUT)/load_address_2097152: load_address.c
-	$(CC) $(CFLAGS) $(LDFLAGS) -Wl,-z,max-page-size=0x200000 -pie $< -o $@
+	$(CC) $(CFLAGS) $(LDFLAGS) -Wl,-z,max-page-size=0x200000 -pie -static $< -o $@
 $(OUTPUT)/load_address_16777216: load_address.c
-	$(CC) $(CFLAGS) $(LDFLAGS) -Wl,-z,max-page-size=0x1000000 -pie $< -o $@
+	$(CC) $(CFLAGS) $(LDFLAGS) -Wl,-z,max-page-size=0x1000000 -pie -static $< -o $@