[folded-merged] kfence-limit-currently-covered-allocations-when-pool-nearly-full-fix.patch removed from -mm tree

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The patch titled
     Subject: kfence-limit-currently-covered-allocations-when-pool-nearly-full-fix
has been removed from the -mm tree.  Its filename was
     kfence-limit-currently-covered-allocations-when-pool-nearly-full-fix.patch

This patch was dropped because it was folded into kfence-limit-currently-covered-allocations-when-pool-nearly-full.patch

------------------------------------------------------
From: Marco Elver <elver@xxxxxxxxxx>
Subject: kfence-limit-currently-covered-allocations-when-pool-nearly-full-fix

* Simplify and just use hash_32().
* Use more random stack_hash_seed.

Link: https://lkml.kernel.org/r/YU3MRGaCaJiYht5g@xxxxxxxxxxxxxxxx
Signed-off-by: Marco Elver <elver@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Aleksandr Nogikh <nogikh@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Taras Madan <tarasmadan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 mm/kfence/core.c |   18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

--- a/mm/kfence/core.c~kfence-limit-currently-covered-allocations-when-pool-nearly-full-fix
+++ a/mm/kfence/core.c
@@ -10,6 +10,7 @@
 #include <linux/atomic.h>
 #include <linux/bug.h>
 #include <linux/debugfs.h>
+#include <linux/hash.h>
 #include <linux/irq_work.h>
 #include <linux/jhash.h>
 #include <linux/kcsan-checks.h>
@@ -122,14 +123,21 @@ atomic_t kfence_allocation_gate = ATOMIC
  *	P(alloc_traces) = (1 - e^(-HNUM * (alloc_traces / SIZE)) ^ HNUM
  */
 #define ALLOC_COVERED_HNUM	2
-#define ALLOC_COVERED_SIZE	(1 << (const_ilog2(CONFIG_KFENCE_NUM_OBJECTS) + 2))
-#define ALLOC_COVERED_HNEXT(h)	(1664525 * (h) + 1013904223)
+#define ALLOC_COVERED_ORDER	(const_ilog2(CONFIG_KFENCE_NUM_OBJECTS) + 2)
+#define ALLOC_COVERED_SIZE	(1 << ALLOC_COVERED_ORDER)
+#define ALLOC_COVERED_HNEXT(h)	hash_32(h, ALLOC_COVERED_ORDER)
 #define ALLOC_COVERED_MASK	(ALLOC_COVERED_SIZE - 1)
 static atomic_t alloc_covered[ALLOC_COVERED_SIZE];
 
 /* Stack depth used to determine uniqueness of an allocation. */
 #define UNIQUE_ALLOC_STACK_DEPTH 8UL
 
+/*
+ * Randomness for stack hashes, making the same collisions across reboots and
+ * different machines less likely.
+ */
+static u32 stack_hash_seed __ro_after_init;
+
 /* Statistics counters for debugfs. */
 enum kfence_counter_id {
 	KFENCE_COUNTER_ALLOCATED,
@@ -166,12 +174,9 @@ static inline bool should_skip_covered(v
 
 static u32 get_alloc_stack_hash(unsigned long *stack_entries, size_t num_entries)
 {
-	/* Some randomness across reboots / different machines. */
-	u32 seed = (u32)((unsigned long)__kfence_pool >> (BITS_PER_LONG - 32));
-
 	num_entries = min(num_entries, UNIQUE_ALLOC_STACK_DEPTH);
 	num_entries = filter_irq_stacks(stack_entries, num_entries);
-	return jhash(stack_entries, num_entries * sizeof(stack_entries[0]), seed);
+	return jhash(stack_entries, num_entries * sizeof(stack_entries[0]), stack_hash_seed);
 }
 
 /*
@@ -759,6 +764,7 @@ void __init kfence_init(void)
 	if (!kfence_sample_interval)
 		return;
 
+	stack_hash_seed = (u32)random_get_entropy();
 	if (!kfence_init_pool()) {
 		pr_err("%s failed\n", __func__);
 		return;
_

Patches currently in -mm which might be from elver@xxxxxxxxxx are

lib-stackdepot-include-gfph.patch
lib-stackdepot-remove-unused-function-argument.patch
lib-stackdepot-introduce-__stack_depot_save.patch
kasan-common-provide-can_alloc-in-kasan_save_stack.patch
kasan-generic-introduce-kasan_record_aux_stack_noalloc.patch
workqueue-kasan-avoid-alloc_pages-when-recording-stack.patch
mm-fix-data-race-in-pagepoisoned.patch
stacktrace-move-filter_irq_stacks-to-kernel-stacktracec.patch
kfence-count-unexpectedly-skipped-allocations.patch
kfence-move-saving-stack-trace-of-allocations-into-__kfence_alloc.patch
kfence-limit-currently-covered-allocations-when-pool-nearly-full.patch
kfence-limit-currently-covered-allocations-when-pool-nearly-full-fix-fix.patch
kfence-add-note-to-documentation-about-skipping-covered-allocations.patch
kfence-test-use-kunit_skip-to-skip-tests.patch
kfence-shorten-critical-sections-of-alloc-free.patch
kfence-always-use-static-branches-to-guard-kfence_alloc.patch
kfence-default-to-dynamic-branch-instead-of-static-keys-mode.patch




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