This is the 4.19.138 stable release

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Merge 4.19.138 into android-4.19-stable

Changes in 4.19.138
	random32: update the net random state on interrupt and activity
	ARM: percpu.h: fix build error
	random: fix circular include dependency on arm64 after addition of percpu.h
	random32: remove net_rand_state from the latent entropy gcc plugin
	random32: move the pseudo-random 32-bit definitions to prandom.h
	ext4: fix direct I/O read error
	Linux 4.19.138

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Icd6c8647a1a5c49b44b9280d9a947f2af6b450db

Makefile

@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 VERSION = 4
 PATCHLEVEL = 19
-SUBLEVEL = 137
+SUBLEVEL = 138
 EXTRAVERSION =
 NAME = "People's Front"
 

arch/arm/include/asm/percpu.h

@@ -16,6 +16,8 @@
 #ifndef _ASM_ARM_PERCPU_H_
 #define _ASM_ARM_PERCPU_H_
 
+#include <asm/thread_info.h>
+
 /*
  * Same as asm-generic/percpu.h, except that we store the per cpu offset
  * in the TPIDRPRW. TPIDRPRW only exists on V6K and V7

drivers/char/random.c

@@ -1249,6 +1249,7 @@ void add_interrupt_randomness(int irq, int irq_flags)
 
 	fast_mix(fast_pool);
 	add_interrupt_bench(cycles);
+	this_cpu_add(net_rand_state.s1, fast_pool->pool[cycles & 3]);
 
 	if (unlikely(crng_init == 0)) {
 		if ((fast_pool->count >= 64) &&

fs/ext4/inode.c

@@ -3885,6 +3885,11 @@ static ssize_t ext4_direct_IO_read(struct kiocb *iocb, struct iov_iter *iter)
 	struct inode *inode = mapping->host;
 	size_t count = iov_iter_count(iter);
 	ssize_t ret;
+	loff_t offset = iocb->ki_pos;
+	loff_t size = i_size_read(inode);
+
+	if (offset >= size)
+		return 0;
 
 	/*
 	 * Shared inode_lock is enough for us - it protects against concurrent

include/linux/prandom.h

@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * include/linux/prandom.h
+ *
+ * Include file for the fast pseudo-random 32-bit
+ * generation.
+ */
+#ifndef _LINUX_PRANDOM_H
+#define _LINUX_PRANDOM_H
+
+#include <linux/types.h>
+#include <linux/percpu.h>
+
+u32 prandom_u32(void);
+void prandom_bytes(void *buf, size_t nbytes);
+void prandom_seed(u32 seed);
+void prandom_reseed_late(void);
+
+struct rnd_state {
+	__u32 s1, s2, s3, s4;
+};
+
+DECLARE_PER_CPU(struct rnd_state, net_rand_state);
+
+u32 prandom_u32_state(struct rnd_state *state);
+void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes);
+void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state);
+
+#define prandom_init_once(pcpu_state)			\
+	DO_ONCE(prandom_seed_full_state, (pcpu_state))
+
+/**
+ * prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro)
+ * @ep_ro: right open interval endpoint
+ *
+ * Returns a pseudo-random number that is in interval [0, ep_ro). Note
+ * that the result depends on PRNG being well distributed in [0, ~0U]
+ * u32 space. Here we use maximally equidistributed combined Tausworthe
+ * generator, that is, prandom_u32(). This is useful when requesting a
+ * random index of an array containing ep_ro elements, for example.
+ *
+ * Returns: pseudo-random number in interval [0, ep_ro)
+ */
+static inline u32 prandom_u32_max(u32 ep_ro)
+{
+	return (u32)(((u64) prandom_u32() * ep_ro) >> 32);
+}
+
+/*
+ * Handle minimum values for seeds
+ */
+static inline u32 __seed(u32 x, u32 m)
+{
+	return (x < m) ? x + m : x;
+}
+
+/**
+ * prandom_seed_state - set seed for prandom_u32_state().
+ * @state: pointer to state structure to receive the seed.
+ * @seed: arbitrary 64-bit value to use as a seed.
+ */
+static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
+{
+	u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
+
+	state->s1 = __seed(i,   2U);
+	state->s2 = __seed(i,   8U);
+	state->s3 = __seed(i,  16U);
+	state->s4 = __seed(i, 128U);
+}
+
+/* Pseudo random number generator from numerical recipes. */
+static inline u32 next_pseudo_random32(u32 seed)
+{
+	return seed * 1664525 + 1013904223;
+}
+
+#endif

include/linux/random.h

@@ -108,61 +108,12 @@ declare_get_random_var_wait(long)
 
 unsigned long randomize_page(unsigned long start, unsigned long range);
 
-u32 prandom_u32(void);
-void prandom_bytes(void *buf, size_t nbytes);
-void prandom_seed(u32 seed);
-void prandom_reseed_late(void);
-
-struct rnd_state {
-	__u32 s1, s2, s3, s4;
-};
-
-u32 prandom_u32_state(struct rnd_state *state);
-void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes);
-void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state);
-
-#define prandom_init_once(pcpu_state)			\
-	DO_ONCE(prandom_seed_full_state, (pcpu_state))
-
-/**
- * prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro)
- * @ep_ro: right open interval endpoint
- *
- * Returns a pseudo-random number that is in interval [0, ep_ro). Note
- * that the result depends on PRNG being well distributed in [0, ~0U]
- * u32 space. Here we use maximally equidistributed combined Tausworthe
- * generator, that is, prandom_u32(). This is useful when requesting a
- * random index of an array containing ep_ro elements, for example.
- *
- * Returns: pseudo-random number in interval [0, ep_ro)
- */
-static inline u32 prandom_u32_max(u32 ep_ro)
-{
-	return (u32)(((u64) prandom_u32() * ep_ro) >> 32);
-}
-
 /*
- * Handle minimum values for seeds
+ * This is designed to be standalone for just prandom
+ * users, but for now we include it from <linux/random.h>
+ * for legacy reasons.
  */
-static inline u32 __seed(u32 x, u32 m)
-{
-	return (x < m) ? x + m : x;
-}
-
-/**
- * prandom_seed_state - set seed for prandom_u32_state().
- * @state: pointer to state structure to receive the seed.
- * @seed: arbitrary 64-bit value to use as a seed.
- */
-static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
-{
-	u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
-
-	state->s1 = __seed(i,   2U);
-	state->s2 = __seed(i,   8U);
-	state->s3 = __seed(i,  16U);
-	state->s4 = __seed(i, 128U);
-}
+#include <linux/prandom.h>
 
 #ifdef CONFIG_ARCH_RANDOM
 # include <asm/archrandom.h>
@@ -185,10 +136,4 @@ static inline bool __must_check arch_get_random_seed_int(unsigned int *v)
 }
 #endif
 
-/* Pseudo random number generator from numerical recipes. */
-static inline u32 next_pseudo_random32(u32 seed)
-{
-	return seed * 1664525 + 1013904223;
-}
-
 #endif /* _LINUX_RANDOM_H */

kernel/time/timer.c

@@ -44,6 +44,7 @@
 #include <linux/sched/debug.h>
 #include <linux/slab.h>
 #include <linux/compat.h>
+#include <linux/random.h>
 
 #include <linux/uaccess.h>
 #include <asm/unistd.h>
@@ -1654,6 +1655,13 @@ void update_process_times(int user_tick)
 	scheduler_tick();
 	if (IS_ENABLED(CONFIG_POSIX_TIMERS))
 		run_posix_cpu_timers(p);
+
+	/* The current CPU might make use of net randoms without receiving IRQs
+	 * to renew them often enough. Let's update the net_rand_state from a
+	 * non-constant value that's not affine to the number of calls to make
+	 * sure it's updated when there's some activity (we don't care in idle).
+	 */
+	this_cpu_add(net_rand_state.s1, rol32(jiffies, 24) + user_tick);
 }
 
 /**

lib/random32.c

@@ -48,7 +48,7 @@ static inline void prandom_state_selftest(void)
 }
 #endif
 
-static DEFINE_PER_CPU(struct rnd_state, net_rand_state) __latent_entropy;
+DEFINE_PER_CPU(struct rnd_state, net_rand_state);
 
 /**
  *	prandom_u32_state - seeded pseudo-random number generator.