AI Trajectory

null

{
  "EnableConfigs": [
    "BLK_INLINE_ENCRYPTION",
    "BLK_INLINE_ENCRYPTION_FALLBACK"
  ],
  "FocusSymbols": [
    "mempool_alloc_bulk_noprof",
    "blk_crypto_fallback_encrypt_work_fn",
    "blk_crypto_fallback_bio_prep"
  ],
  "Reasoning": "The patch modifies `mempool_alloc_bulk_noprof` to accept a `gfp_mask` and handle allocation failures properly. It also updates `blk-crypto-fallback` to use this new signature and introduces a workqueue (`enc_rescue_work`) to prevent deadlocks during recursive bio submissions by punting encryption work when `current-\u003ebio_list` is non-null. This is a functional change in core memory management and block layer crypto fallback logic, which is reachable in virtualized environments.",
  "WorthFuzzing": true
}

null

{
  "PatchDiff": "commit a12a52bc154d9add823737659458e68820ffd506\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Fri Aug 7 02:05:33 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/block/blk-crypto-fallback.c b/block/blk-crypto-fallback.c\nindex 2a5c52ab74b4c..973399011d5a2 100644\n--- a/block/blk-crypto-fallback.c\n+++ b/block/blk-crypto-fallback.c\n@@ -83,6 +83,10 @@ static struct workqueue_struct *blk_crypto_wq;\n static mempool_t *blk_crypto_bounce_page_pool;\n static struct bio_set enc_bio_set;\n \n+static DEFINE_SPINLOCK(enc_rescue_list_lock);\n+static struct bio_list enc_rescue_list;\n+static struct work_struct enc_rescue_work;\n+\n /*\n  * This is the key we set when evicting a keyslot. This *should* be the all 0's\n  * key, but AES-XTS rejects that key, so we use some random bytes instead.\n@@ -172,13 +176,26 @@ static void blk_crypto_fallback_encrypt_endio(struct bio *enc_bio)\n static struct bio *blk_crypto_alloc_enc_bio(struct bio *bio_src,\n \t\tunsigned int nr_segs, struct page ***pages_ret)\n {\n-\tunsigned int memflags = memalloc_noio_save();\n \tunsigned int nr_allocated;\n \tstruct page **pages;\n \tstruct bio *bio;\n+\tgfp_t gfp_mask;\n+\n+\t/*\n+\t * During recursive bio submission (current-\u003ebio_list != NULL) any\n+\t * submitted bounce bios just get added to current-\u003ebio_list; they\n+\t * cannot complete and release resources yet.  Therefore, to avoid\n+\t * deadlocks, don't wait indefinitely for additional resources.\n+\t */\n+\tif (current-\u003ebio_list)\n+\t\tgfp_mask = GFP_NOWAIT;\n+\telse\n+\t\tgfp_mask = GFP_NOIO;\n \n \tbio = bio_alloc_bioset(bio_src-\u003ebi_bdev, nr_segs, bio_src-\u003ebi_opf,\n-\t\t\tGFP_NOIO, \u0026enc_bio_set);\n+\t\t\t       gfp_mask, \u0026enc_bio_set);\n+\tif (unlikely(!bio))\n+\t\treturn NULL;\n \tif (bio_flagged(bio_src, BIO_REMAPPED))\n \t\tbio_set_flag(bio, BIO_REMAPPED);\n \tbio-\u003ebi_private\t\t= bio_src;\n@@ -206,12 +223,15 @@ static struct bio *blk_crypto_alloc_enc_bio(struct bio *bio_src,\n \t * any non-zero slot already contains a valid allocation.\n \t */\n \tmemset(pages, 0, sizeof(struct page *) * nr_segs);\n-\tnr_allocated = alloc_pages_bulk(GFP_KERNEL, nr_segs, pages);\n-\tif (nr_allocated \u003c nr_segs)\n-\t\tmempool_alloc_bulk(blk_crypto_bounce_page_pool,\n+\tnr_allocated = alloc_pages_bulk(gfp_mask, nr_segs, pages);\n+\tif (unlikely(nr_allocated \u003c nr_segs) \u0026\u0026\n+\t    !mempool_alloc_bulk(blk_crypto_bounce_page_pool,\n \t\t\t\t(void **)pages + nr_allocated,\n-\t\t\t\tnr_segs - nr_allocated);\n-\tmemalloc_noio_restore(memflags);\n+\t\t\t\tnr_segs - nr_allocated, gfp_mask)) {\n+\t\tfree_pages_bulk(pages, nr_allocated);\n+\t\tbio_put(bio);\n+\t\treturn NULL;\n+\t}\n \t*pages_ret = pages;\n \treturn bio;\n }\n@@ -239,6 +259,25 @@ static void blk_crypto_dun_to_iv(const u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE],\n \t\tiv-\u003edun[i] = cpu_to_le64(dun[i]);\n }\n \n+static void blk_crypto_fallback_encrypt_bio(struct bio *src_bio);\n+\n+/* Encrypt a list of bios whose encryption was punted to a kworker. */\n+static void blk_crypto_fallback_encrypt_work_fn(struct work_struct *work)\n+{\n+\tstruct bio_list list;\n+\tstruct bio *src_bio;\n+\n+\tWARN_ON_ONCE(current-\u003ebio_list);\n+\n+\tspin_lock(\u0026enc_rescue_list_lock);\n+\tlist = enc_rescue_list;\n+\tbio_list_init(\u0026enc_rescue_list);\n+\tspin_unlock(\u0026enc_rescue_list_lock);\n+\n+\twhile ((src_bio = bio_list_pop(\u0026list)))\n+\t\tblk_crypto_fallback_encrypt_bio(src_bio);\n+}\n+\n static void __blk_crypto_fallback_encrypt_bio(struct bio *src_bio,\n \t\tstruct crypto_sync_skcipher *tfm)\n {\n@@ -273,6 +312,23 @@ static void __blk_crypto_fallback_encrypt_bio(struct bio *src_bio,\n new_bio:\n \tnr_enc_pages = min(bio_segments(src_bio), BIO_MAX_VECS);\n \tenc_bio = blk_crypto_alloc_enc_bio(src_bio, nr_enc_pages, \u0026enc_pages);\n+\tif (unlikely(!enc_bio)) {\n+\t\t/*\n+\t\t * Failed to allocate a bounce bio during recursive bio\n+\t\t * submission.  We might be blocked on bios in current-\u003ebio_list\n+\t\t * holding mempool elements.  To enable forward progress, punt\n+\t\t * the remaining encryption work for src_bio to a kworker.\n+\t\t *\n+\t\t * The DUN may have been advanced, so make sure to update it.\n+\t\t */\n+\t\tWARN_ON_ONCE(!current-\u003ebio_list);\n+\t\tmemcpy(bc-\u003ebc_dun, curr_dun, sizeof(curr_dun));\n+\t\tspin_lock(\u0026enc_rescue_list_lock);\n+\t\tbio_list_add(\u0026enc_rescue_list, src_bio);\n+\t\tspin_unlock(\u0026enc_rescue_list_lock);\n+\t\tqueue_work(blk_crypto_wq, \u0026enc_rescue_work);\n+\t\treturn;\n+\t}\n \tenc_idx = 0;\n \tfor (;;) {\n \t\tstruct bio_vec src_bv =\n@@ -591,6 +647,8 @@ static int blk_crypto_fallback_init(void)\n \tif (!bio_fallback_crypt_ctx_pool)\n \t\tgoto fail_free_crypt_ctx_cache;\n \n+\tINIT_WORK(\u0026enc_rescue_work, blk_crypto_fallback_encrypt_work_fn);\n+\n \tblk_crypto_fallback_inited = true;\n \n \treturn 0;\ndiff --git a/include/linux/mempool.h b/include/linux/mempool.h\nindex a0fa6d43e0dc4..f7898cd1512ba 100644\n--- a/include/linux/mempool.h\n+++ b/include/linux/mempool.h\n@@ -65,8 +65,8 @@ void mempool_destroy(struct mempool *pool);\n void *mempool_alloc_noprof(struct mempool *pool, gfp_t gfp_mask) __malloc;\n #define mempool_alloc(...)\t\t\t\t\t\t\\\n \talloc_hooks(mempool_alloc_noprof(__VA_ARGS__))\n-int mempool_alloc_bulk_noprof(struct mempool *pool, void **elem,\n-\t\tunsigned int count);\n+bool mempool_alloc_bulk_noprof(struct mempool *pool, void **elem,\n+\t\tunsigned int count, gfp_t gfp_mask);\n #define mempool_alloc_bulk(...)\t\t\t\t\t\t\\\n \talloc_hooks(mempool_alloc_bulk_noprof(__VA_ARGS__))\n \ndiff --git a/mm/mempool.c b/mm/mempool.c\nindex 473a029fa31fd..d741e5f625543 100644\n--- a/mm/mempool.c\n+++ b/mm/mempool.c\n@@ -409,7 +409,7 @@ int mempool_resize(struct mempool *pool, int new_min_nr)\n }\n EXPORT_SYMBOL(mempool_resize);\n \n-static unsigned int mempool_alloc_from_pool(struct mempool *pool, void **elems,\n+static bool mempool_alloc_from_pool(struct mempool *pool, void **elems,\n \t\tunsigned int count, unsigned int allocated,\n \t\tgfp_t gfp_mask)\n {\n@@ -432,7 +432,7 @@ static unsigned int mempool_alloc_from_pool(struct mempool *pool, void **elems,\n \t */\n \tfor (i = 0; i \u003c count; i++)\n \t\tkmemleak_update_trace(elems[i]);\n-\treturn allocated;\n+\treturn true;\n \n fail:\n \tif (gfp_mask \u0026 __GFP_DIRECT_RECLAIM) {\n@@ -454,7 +454,7 @@ static unsigned int mempool_alloc_from_pool(struct mempool *pool, void **elems,\n \t\tspin_unlock_irqrestore(\u0026pool-\u003elock, flags);\n \t}\n \n-\treturn allocated;\n+\treturn false;\n }\n \n /*\n@@ -473,25 +473,28 @@ static inline gfp_t mempool_adjust_gfp(gfp_t *gfp_mask)\n /**\n  * mempool_alloc_bulk - allocate multiple elements from a memory pool\n  * @pool:\tpointer to the memory pool\n- * @elems:\tpartially or fully populated elements array\n- * @count:\tnumber of entries in @elem that need to be allocated\n+ * @elems:\tpointer to array into which the element pointers will be stored\n+ * @count:\tnumber of elements to allocate\n+ * @gfp_mask:\tGFP_* flags.  %__GFP_ZERO is not supported.  If this mask\n+ *\t\tincludes %__GFP_DIRECT_RECLAIM, then the allocation is retried\n+ *\t\tindefinitely until it succeeds and the return value is always\n+ *\t\t%true.  If the mask doesn't include %__GFP_DIRECT_RECLAIM, then\n+ *\t\tfailure is allowed and %false can be returned.\n  *\n  * Allocate @count elements into @elems.  This is done by first calling into the\n  * alloc_fn supplied at pool initialization time, and dipping into the reserved\n- * pool when alloc_fn fails to allocate an element.\n- *\n- * On return all @count elements in @elems will be populated.\n+ * pool to atomically allocate the remaining elements if alloc_fn fails.\n  *\n- * Return: Always 0.  If it wasn't for %$#^$ alloc tags, it would return void.\n+ * Return: %true if the allocation succeeded, or %false if it failed.\n  */\n-int mempool_alloc_bulk_noprof(struct mempool *pool, void **elems,\n-\t\tunsigned int count)\n+bool mempool_alloc_bulk_noprof(struct mempool *pool, void **elems,\n+\t\tunsigned int count, gfp_t gfp_mask)\n {\n-\tgfp_t gfp_mask = GFP_KERNEL;\n \tgfp_t gfp_temp = mempool_adjust_gfp(\u0026gfp_mask);\n \tunsigned int allocated = 0;\n \n \tVM_WARN_ON_ONCE(count \u003e pool-\u003emin_nr);\n+\tVM_WARN_ON_ONCE(gfp_mask \u0026 __GFP_ZERO);\n \tmight_alloc(gfp_mask);\n \n \t/*\n@@ -516,13 +519,26 @@ int mempool_alloc_bulk_noprof(struct mempool *pool, void **elems,\n \t\tallocated++;\n \t}\n \n-\treturn 0;\n+\treturn true;\n \n use_pool:\n-\tallocated = mempool_alloc_from_pool(pool, elems, count, allocated,\n-\t\t\tgfp_temp);\n-\tgfp_temp = gfp_mask;\n-\tgoto repeat_alloc;\n+\t/* Try to atomically allocate the remaining elements from the pool. */\n+\tif (mempool_alloc_from_pool(pool, elems, count, allocated, gfp_temp))\n+\t\treturn true;\n+\t/* Retry if this was just the opportunistic first pass. */\n+\tif (gfp_temp != gfp_mask) {\n+\t\tgfp_temp = gfp_mask;\n+\t\tgoto repeat_alloc;\n+\t}\n+\t/* Retry indefinitely if __GFP_DIRECT_RECLAIM is set. */\n+\tif (gfp_mask \u0026 __GFP_DIRECT_RECLAIM)\n+\t\tgoto repeat_alloc;\n+\t/* On failure, roll back any successful allocations from -\u003ealloc(). */\n+\twhile (allocated--) {\n+\t\tpool-\u003efree(elems[allocated], pool-\u003epool_data);\n+\t\telems[allocated] = NULL;\n+\t}\n+\treturn false;\n }\n EXPORT_SYMBOL_GPL(mempool_alloc_bulk_noprof);\n \n"
}

best-expensive

null

{
  "EnableConfigs": [
    "BLK_INLINE_ENCRYPTION",
    "BLK_INLINE_ENCRYPTION_FALLBACK"
  ],
  "FocusSymbols": [
    "mempool_alloc_bulk_noprof",
    "blk_crypto_fallback_encrypt_work_fn",
    "blk_crypto_fallback_bio_prep"
  ],
  "Reasoning": "The patch modifies `mempool_alloc_bulk_noprof` to accept a `gfp_mask` and handle allocation failures properly. It also updates `blk-crypto-fallback` to use this new signature and introduces a workqueue (`enc_rescue_work`) to prevent deadlocks during recursive bio submissions by punting encryption work when `current-\u003ebio_list` is non-null. This is a functional change in core memory management and block layer crypto fallback logic, which is reachable in virtualized environments.",
  "WorthFuzzing": true
}

You are an expert Linux kernel maintainer.
Your job is to review a provided patch series and determine
if it makes functional changes to the kernel that should be fuzzed.

IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in
your workspace. Do NOT rely on your internal knowledge of the kernel. You must actively
use your code access tools to examine the actual source code and confirm any assumptions.

Return WorthFuzzing=false if the patch only contains:
- Modifications to Documentation/, Kconfig files, or code comments.
- Purely decorative changes, such as logging (e.g., pr_err, printk) or tracepoints.
- Changes to numeric constants or macros that do not functionally alter execution flow.
- Code paths that are impossible to reach in virtualized environments like GCE or QEMU,
  even when utilizing software-emulated hardware (e.g., usb gadget, mac80211_hwsim).
- Code in vendor-specific PCIe switch, SmartNIC, or GPU drivers (e.g., mlxsw, pds_core, qed,
  ionic, amdgpu) that require physical PCIe hardware cards not emulated in standard QEMU.
- Driver .remove, .shutdown, or pci_unregister_driver teardown callbacks (e.g., igb_remove)
  that are executed only during PCI hot-unplug or sysfs driver unbind operations.

If it modifies reachable core kernel logic, drivers, or architectures, use your code search
tools to verify the code can be executed, then return WorthFuzzing=true.

When returning WorthFuzzing=true, you MUST ALSO:
1. Extract any specific kernel functions that should be heavily fuzzed into FocusSymbols.
   Avoid listing generic hot-path functions to prevent skewed test distributions.
   Prefer non-static, non-inlined API entrypoint functions over internal static helper functions
   (which are inlined by the compiler and do not have distinct symbol addresses).
2. Identify any specific CONFIG_ options required to properly test this new/modified feature.
   Go and look into the Kconfig files and check for ifdefs around the code, do not make assumptions.
   Also check "depends on" lines in Kconfig to include any non-standard parent subsystem configs
   needed for Kbuild to compile the code statically into vmlinux. List them in the EnableConfigs
   output array, and DO NOT add a 'CONFIG_' prefix (e.g., return "NET_IPV4" instead of "CONFIG_NET_IPV4").
Prefer calling several tools at the same time to save round-trips.


Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.

For your convenience, here is the diff of the changes:
commit a12a52bc154d9add823737659458e68820ffd506
Author: syz-cluster <triage@syzkaller.com>
Date:   Fri Aug 7 02:05:33 2026 +0000

    syz-cluster: applied patch under review

diff --git a/block/blk-crypto-fallback.c b/block/blk-crypto-fallback.c
index 2a5c52ab74b4c..973399011d5a2 100644
--- a/block/blk-crypto-fallback.c
+++ b/block/blk-crypto-fallback.c
@@ -83,6 +83,10 @@ static struct workqueue_struct *blk_crypto_wq;
 static mempool_t *blk_crypto_bounce_page_pool;
 static struct bio_set enc_bio_set;
 
+static DEFINE_SPINLOCK(enc_rescue_list_lock);
+static struct bio_list enc_rescue_list;
+static struct work_struct enc_rescue_work;
+
 /*
  * This is the key we set when evicting a keyslot. This *should* be the all 0's
  * key, but AES-XTS rejects that key, so we use some random bytes instead.
@@ -172,13 +176,26 @@ static void blk_crypto_fallback_encrypt_endio(struct bio *enc_bio)
 static struct bio *blk_crypto_alloc_enc_bio(struct bio *bio_src,
 		unsigned int nr_segs, struct page ***pages_ret)
 {
-	unsigned int memflags = memalloc_noio_save();
 	unsigned int nr_allocated;
 	struct page **pages;
 	struct bio *bio;
+	gfp_t gfp_mask;
+
+	/*
+	 * During recursive bio submission (current->bio_list != NULL) any
+	 * submitted bounce bios just get added to current->bio_list; they
+	 * cannot complete and release resources yet.  Therefore, to avoid
+	 * deadlocks, don't wait indefinitely for additional resources.
+	 */
+	if (current->bio_list)
+		gfp_mask = GFP_NOWAIT;
+	else
+		gfp_mask = GFP_NOIO;
 
 	bio = bio_alloc_bioset(bio_src->bi_bdev, nr_segs, bio_src->bi_opf,
-			GFP_NOIO, &enc_bio_set);
+			       gfp_mask, &enc_bio_set);
+	if (unlikely(!bio))
+		return NULL;
 	if (bio_flagged(bio_src, BIO_REMAPPED))
 		bio_set_flag(bio, BIO_REMAPPED);
 	bio->bi_private		= bio_src;
@@ -206,12 +223,15 @@ static struct bio *blk_crypto_alloc_enc_bio(struct bio *bio_src,
 	 * any non-zero slot already contains a valid allocation.
 	 */
 	memset(pages, 0, sizeof(struct page *) * nr_segs);
-	nr_allocated = alloc_pages_bulk(GFP_KERNEL, nr_segs, pages);
-	if (nr_allocated < nr_segs)
-		mempool_alloc_bulk(blk_crypto_bounce_page_pool,
+	nr_allocated = alloc_pages_bulk(gfp_mask, nr_segs, pages);
+	if (unlikely(nr_allocated < nr_segs) &&
+	    !mempool_alloc_bulk(blk_crypto_bounce_page_pool,
 				(void **)pages + nr_allocated,
-				nr_segs - nr_allocated);
-	memalloc_noio_restore(memflags);
+				nr_segs - nr_allocated, gfp_mask)) {
+		free_pages_bulk(pages, nr_allocated);
+		bio_put(bio);
+		return NULL;
+	}
 	*pages_ret = pages;
 	return bio;
 }
@@ -239,6 +259,25 @@ static void blk_crypto_dun_to_iv(const u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE],
 		iv->dun[i] = cpu_to_le64(dun[i]);
 }
 
+static void blk_crypto_fallback_encrypt_bio(struct bio *src_bio);
+
+/* Encrypt a list of bios whose encryption was punted to a kworker. */
+static void blk_crypto_fallback_encrypt_work_fn(struct work_struct *work)
+{
+	struct bio_list list;
+	struct bio *src_bio;
+
+	WARN_ON_ONCE(current->bio_list);
+
+	spin_lock(&enc_rescue_list_lock);
+	list = enc_rescue_list;
+	bio_list_init(&enc_rescue_list);
+	spin_unlock(&enc_rescue_list_lock);
+
+	while ((src_bio = bio_list_pop(&list)))
+		blk_crypto_fallback_encrypt_bio(src_bio);
+}
+
 static void __blk_crypto_fallback_encrypt_bio(struct bio *src_bio,
 		struct crypto_sync_skcipher *tfm)
 {
@@ -273,6 +312,23 @@ static void __blk_crypto_fallback_encrypt_bio(struct bio *src_bio,
 new_bio:
 	nr_enc_pages = min(bio_segments(src_bio), BIO_MAX_VECS);
 	enc_bio = blk_crypto_alloc_enc_bio(src_bio, nr_enc_pages, &enc_pages);
+	if (unlikely(!enc_bio)) {
+		/*
+		 * Failed to allocate a bounce bio during recursive bio
+		 * submission.  We might be blocked on bios in current->bio_list
+		 * holding mempool elements.  To enable forward progress, punt
+		 * the remaining encryption work for src_bio to a kworker.
+		 *
+		 * The DUN may have been advanced, so make sure to update it.
+		 */
+		WARN_ON_ONCE(!current->bio_list);
+		memcpy(bc->bc_dun, curr_dun, sizeof(curr_dun));
+		spin_lock(&enc_rescue_list_lock);
+		bio_list_add(&enc_rescue_list, src_bio);
+		spin_unlock(&enc_rescue_list_lock);
+		queue_work(blk_crypto_wq, &enc_rescue_work);
+		return;
+	}
 	enc_idx = 0;
 	for (;;) {
 		struct bio_vec src_bv =
@@ -591,6 +647,8 @@ static int blk_crypto_fallback_init(void)
 	if (!bio_fallback_crypt_ctx_pool)
 		goto fail_free_crypt_ctx_cache;
 
+	INIT_WORK(&enc_rescue_work, blk_crypto_fallback_encrypt_work_fn);
+
 	blk_crypto_fallback_inited = true;
 
 	return 0;
diff --git a/include/linux/mempool.h b/include/linux/mempool.h
index a0fa6d43e0dc4..f7898cd1512ba 100644
--- a/include/linux/mempool.h
+++ b/include/linux/mempool.h
@@ -65,8 +65,8 @@ void mempool_destroy(struct mempool *pool);
 void *mempool_alloc_noprof(struct mempool *pool, gfp_t gfp_mask) __malloc;
 #define mempool_alloc(...)						\
 	alloc_hooks(mempool_alloc_noprof(__VA_ARGS__))
-int mempool_alloc_bulk_noprof(struct mempool *pool, void **elem,
-		unsigned int count);
+bool mempool_alloc_bulk_noprof(struct mempool *pool, void **elem,
+		unsigned int count, gfp_t gfp_mask);
 #define mempool_alloc_bulk(...)						\
 	alloc_hooks(mempool_alloc_bulk_noprof(__VA_ARGS__))
 
diff --git a/mm/mempool.c b/mm/mempool.c
index 473a029fa31fd..d741e5f625543 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -409,7 +409,7 @@ int mempool_resize(struct mempool *pool, int new_min_nr)
 }
 EXPORT_SYMBOL(mempool_resize);
 
-static unsigned int mempool_alloc_from_pool(struct mempool *pool, void **elems,
+static bool mempool_alloc_from_pool(struct mempool *pool, void **elems,
 		unsigned int count, unsigned int allocated,
 		gfp_t gfp_mask)
 {
@@ -432,7 +432,7 @@ static unsigned int mempool_alloc_from_pool(struct mempool *pool, void **elems,
 	 */
 	for (i = 0; i < count; i++)
 		kmemleak_update_trace(elems[i]);
-	return allocated;
+	return true;
 
 fail:
 	if (gfp_mask & __GFP_DIRECT_RECLAIM) {
@@ -454,7 +454,7 @@ static unsigned int mempool_alloc_from_pool(struct mempool *pool, void **elems,
 		spin_unlock_irqrestore(&pool->lock, flags);
 	}
 
-	return allocated;
+	return false;
 }
 
 /*
@@ -473,25 +473,28 @@ static inline gfp_t mempool_adjust_gfp(gfp_t *gfp_mask)
 /**
  * mempool_alloc_bulk - allocate multiple elements from a memory pool
  * @pool:	pointer to the memory pool
- * @elems:	partially or fully populated elements array
- * @count:	number of entries in @elem that need to be allocated
+ * @elems:	pointer to array into which the element pointers will be stored
+ * @count:	number of elements to allocate
+ * @gfp_mask:	GFP_* flags.  %__GFP_ZERO is not supported.  If this mask
+ *		includes %__GFP_DIRECT_RECLAIM, then the allocation is retried
+ *		indefinitely until it succeeds and the return value is always
+ *		%true.  If the mask doesn't include %__GFP_DIRECT_RECLAIM, then
+ *		failure is allowed and %false can be returned.
  *
  * Allocate @count elements into @elems.  This is done by first calling into the
  * alloc_fn supplied at pool initialization time, and dipping into the reserved
- * pool when alloc_fn fails to allocate an element.
- *
- * On return all @count elements in @elems will be populated.
+ * pool to atomically allocate the remaining elements if alloc_fn fails.
  *
- * Return: Always 0.  If it wasn't for %$#^$ alloc tags, it would return void.
+ * Return: %true if the allocation succeeded, or %false if it failed.
  */
-int mempool_alloc_bulk_noprof(struct mempool *pool, void **elems,
-		unsigned int count)
+bool mempool_alloc_bulk_noprof(struct mempool *pool, void **elems,
+		unsigned int count, gfp_t gfp_mask)
 {
-	gfp_t gfp_mask = GFP_KERNEL;
 	gfp_t gfp_temp = mempool_adjust_gfp(&gfp_mask);
 	unsigned int allocated = 0;
 
 	VM_WARN_ON_ONCE(count > pool->min_nr);
+	VM_WARN_ON_ONCE(gfp_mask & __GFP_ZERO);
 	might_alloc(gfp_mask);
 
 	/*
@@ -516,13 +519,26 @@ int mempool_alloc_bulk_noprof(struct mempool *pool, void **elems,
 		allocated++;
 	}
 
-	return 0;
+	return true;
 
 use_pool:
-	allocated = mempool_alloc_from_pool(pool, elems, count, allocated,
-			gfp_temp);
-	gfp_temp = gfp_mask;
-	goto repeat_alloc;
+	/* Try to atomically allocate the remaining elements from the pool. */
+	if (mempool_alloc_from_pool(pool, elems, count, allocated, gfp_temp))
+		return true;
+	/* Retry if this was just the opportunistic first pass. */
+	if (gfp_temp != gfp_mask) {
+		gfp_temp = gfp_mask;
+		goto repeat_alloc;
+	}
+	/* Retry indefinitely if __GFP_DIRECT_RECLAIM is set. */
+	if (gfp_mask & __GFP_DIRECT_RECLAIM)
+		goto repeat_alloc;
+	/* On failure, roll back any successful allocations from ->alloc(). */
+	while (allocated--) {
+		pool->free(elems[allocated], pool->pool_data);
+		elems[allocated] = NULL;
+	}
+	return false;
 }
 EXPORT_SYMBOL_GPL(mempool_alloc_bulk_noprof);
 

gemini-3.1-pro-preview

null

null

							input: 5145
							output: 27
							thoughts: 208
						

**Analyzing a Patch: Block Crypto Fallback and Memory Pool Changes**

Okay, so I'm looking at this patch and immediately see it's touching `block/blk-crypto-fallback.c` and `mm/mempool.c`. My spidey-sense is tingling – anytime we're messing with memory allocation and the block layer, I pay close attention. Specifically, the patch is changing the `mempool_alloc_bulk_noprof` function. Previously, it just *always* succeeded and returned 0, but now it's going to take a `gfp_mask` for memory allocation flags and return a boolean indicating success or failure. That's a fundamental shift in how we handle memory pool allocation. It's a non-trivial change.

Now, it updates `blk_crypto_alloc_enc_bio` to use the new `mempool_alloc_bulk` signature. This is where things get interesting. The important part is how the patch handles allocation failures. Instead of just chugging along, if the `mempool_alloc_bulk` call fails, it now punts to a workqueue, `enc_rescue_work`, but *only* if `current->bio_list` isn't null. I'm guessing that the check for the `bio_list` helps avoid a deadlock scenario. That's a classic strategy when dealing with potential resource contention. That's a good way to handle a critical failure.

Functionally, this is a change to block crypto fallback and mempool allocation, and it's something I need to evaluate. Next, I need to understand whether this is something that QEMU could actually hit. We're talking about block crypto fallback, so I'll need to know if `CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK` is enabled. That should be a straightforward Kconfig check to make sure it's possible.

{
  "Expression": "config BLK_INLINE_ENCRYPTION_FALLBACK"
}

{
  "Output": "block/Kconfig=195=config BLK_INLINE_ENCRYPTION\n--\nblock/Kconfig-201-\nblock/Kconfig:202:config BLK_INLINE_ENCRYPTION_FALLBACK\nblock/Kconfig-203-\tbool \"Enable crypto API fallback for blk-crypto\"\n"
}

gemini-3.1-pro-preview

null

null

							input: 5880
							output: 32
							thoughts: 24
						

Okay, here's my interpretation of that thought process, assuming I'm an expert in this field, and rendered in the first person:

**Investigating the Encryption Fallback Mechanism**

Alright, I need to understand this `BLK_INLINE_ENCRYPTION_FALLBACK` option. My initial thought is to dive straight into `block/Kconfig`. That's the logical place to start digging into the configuration options for this subsystem. I know that's where I'll find the definition, dependencies, and likely some documentation or comments about what this fallback mechanism is intended to do. Hopefully, the Kconfig entry will also give me clues about *why* we might need a fallback for inline encryption. This could involve looking at any dependencies and examining how it interacts with other features or hardware configurations. I'm expecting this `Kconfig` file to provide the necessary framework to understand the design choices behind the feature. From there, I can begin to drill down into the underlying code if necessary.

{
  "File": "block/Kconfig",
  "FirstLine": 195,
  "LineCount": 20
}

{
  "Contents": " 195:\tconfig BLK_INLINE_ENCRYPTION\n 196:\t\tbool \"Enable inline encryption support in block layer\"\n 197:\t\thelp\n 198:\t\t  Build the blk-crypto subsystem. Enabling this lets the\n 199:\t\t  block layer handle encryption, so users can take\n 200:\t\t  advantage of inline encryption hardware if present.\n 201:\t\n 202:\tconfig BLK_INLINE_ENCRYPTION_FALLBACK\n 203:\t\tbool \"Enable crypto API fallback for blk-crypto\"\n 204:\t\tdepends on BLK_INLINE_ENCRYPTION\n 205:\t\tselect CRYPTO\n 206:\t\tselect CRYPTO_SKCIPHER\n 207:\t\thelp\n 208:\t\t  Enabling this lets the block layer handle inline encryption\n 209:\t\t  by falling back to the kernel crypto API when inline\n 210:\t\t  encryption hardware is not present.\n 211:\t\n 212:\tsource \"block/partitions/Kconfig\"\n 213:\t\n 214:\tconfig BLK_PM\n"
}

gemini-3.1-pro-preview

null

null

							input: 6440
							output: 21
							thoughts: 83
						

**Considering the Cryptographic Block Device Changes**

Okay, so the immediate need is to implement both `BLK_INLINE_ENCRYPTION` and `BLK_INLINE_ENCRYPTION_FALLBACK`. That seems straightforward enough, but I need to be careful. Hold on, the patch touches `mm/mempool.c` too. Interesting. Specifically, it modifies the `mempool_alloc_bulk` function, and that's used by `blk_crypto_alloc_enc_bio`. I need to ensure there are no unintended consequences. What other subsystems or drivers rely on `mempool_alloc_bulk`? I need to review *all* of the `mempool_alloc_bulk` uses. I don't want to break something unrelated.

{
  "Expression": "mempool_alloc_bulk"
}

{
  "Output": "block/blk-crypto-fallback.c=176=static struct bio *blk_crypto_alloc_enc_bio(struct bio *bio_src,\n--\nblock/blk-crypto-fallback.c-219-\t * Try a bulk allocation first.  This might not fill all allocated\nblock/blk-crypto-fallback.c:220:\t * pages, but we'll fix that up later in mempool_alloc_bulk.\nblock/blk-crypto-fallback.c-221-\t *\n--\nblock/blk-crypto-fallback.c-227-\tif (unlikely(nr_allocated \u003c nr_segs) \u0026\u0026\nblock/blk-crypto-fallback.c:228:\t    !mempool_alloc_bulk(blk_crypto_bounce_page_pool,\nblock/blk-crypto-fallback.c-229-\t\t\t\t(void **)pages + nr_allocated,\n--\ninclude/linux/mempool.h=65=void *mempool_alloc_noprof(struct mempool *pool, gfp_t gfp_mask) __malloc;\n--\ninclude/linux/mempool.h-67-\talloc_hooks(mempool_alloc_noprof(__VA_ARGS__))\ninclude/linux/mempool.h:68:bool mempool_alloc_bulk_noprof(struct mempool *pool, void **elem,\ninclude/linux/mempool.h-69-\t\tunsigned int count, gfp_t gfp_mask);\ninclude/linux/mempool.h:70:#define mempool_alloc_bulk(...)\t\t\t\t\t\t\\\ninclude/linux/mempool.h:71:\talloc_hooks(mempool_alloc_bulk_noprof(__VA_ARGS__))\ninclude/linux/mempool.h-72-\n--\nmm/mempool.c=21=static DECLARE_FAULT_ATTR(fail_mempool_alloc);\nmm/mempool.c:22:static DECLARE_FAULT_ATTR(fail_mempool_alloc_bulk);\nmm/mempool.c-23-\nmm/mempool.c=24=static int __init mempool_faul_inject_init(void)\n--\nmm/mempool.c-34-\treturn PTR_ERR_OR_ZERO(\nmm/mempool.c:35:\t\tfault_create_debugfs_attr(\"fail_mempool_alloc_bulk\", NULL,\nmm/mempool.c:36:\t\t\u0026fail_mempool_alloc_bulk));\nmm/mempool.c-37-}\n--\nmm/mempool.c=467=static inline gfp_t mempool_adjust_gfp(gfp_t *gfp_mask)\n--\nmm/mempool.c-473-/**\nmm/mempool.c:474: * mempool_alloc_bulk - allocate multiple elements from a memory pool\nmm/mempool.c-475- * @pool:\tpointer to the memory pool\n--\nmm/mempool.c-489- */\nmm/mempool.c:490:bool mempool_alloc_bulk_noprof(struct mempool *pool, void **elems,\nmm/mempool.c-491-\t\tunsigned int count, gfp_t gfp_mask)\n--\nmm/mempool.c-503-\t */\nmm/mempool.c:504:\tif (should_fail_ex(\u0026fail_mempool_alloc_bulk, 1, FAULT_NOWARN)) {\nmm/mempool.c-505-\t\tpr_info(\"forcing mempool usage for %pS\\n\",\n--\nmm/mempool.c-542-}\nmm/mempool.c:543:EXPORT_SYMBOL_GPL(mempool_alloc_bulk_noprof);\nmm/mempool.c-544-\n"
}

gemini-3.1-pro-preview

null

null

							input: 7680
							output: 24
							thoughts: 393
						

**Analyzing Block Crypto Fallback Logic**

Okay, so I'm diving into this block crypto fallback implementation. It looks like `mempool_alloc_bulk` is exclusively used within `block/blk-crypto-fallback.c`, which makes sense. This module introduces a new workqueue, `enc_rescue_work`, and the associated worker function `blk_crypto_fallback_encrypt_work_fn`. The core change is in `blk_crypto_alloc_enc_bio`. It now attempts a non-blocking allocation (`GFP_NOWAIT`) using `mempool_alloc_bulk_noprof` if `current->bio_list` is populated, and if that fails, it offloads the request to the new workqueue. This fallback logic kicks in during block crypto operations, of course.

To test this thoroughly, I should enable `BLK_INLINE_ENCRYPTION_FALLBACK`. The crucial symbols to focus on during debugging and analysis are: `blk_crypto_fallback_encrypt_work_fn`, `blk_crypto_alloc_enc_bio`, and `mempool_alloc_bulk_noprof`.

Hang on, `mempool_alloc_bulk_noprof` is a core function, but it's only used by `blk_crypto_alloc_enc_bio` in this specific context, which is worth noting. Now, the prompt says to prefer non-static, non-inlined entry points. Let me see... `blk_crypto_fallback_encrypt_work_fn` *is* static... But wait, it's passed to `INIT_WORK`. This means it isn't inlined, it has a distinct symbol address. That satisfies the requirement, thankfully. Now, `blk_crypto_alloc_enc_bio` is static, which is a bit less ideal, but it's called by `__blk_crypto_fallback_encrypt_bio` which is also static. Let's dig deeper to find the *actual* entry points for the block crypto fallback.

{
  "Expression": "__blk_crypto_fallback_encrypt_bio"
}

{
  "Output": "block/blk-crypto-fallback.c=265=static void blk_crypto_fallback_encrypt_work_fn(struct work_struct *work)\n--\nblock/blk-crypto-fallback.c-280-\nblock/blk-crypto-fallback.c:281:static void __blk_crypto_fallback_encrypt_bio(struct bio *src_bio,\nblock/blk-crypto-fallback.c-282-\t\tstruct crypto_sync_skcipher *tfm)\n--\nblock/blk-crypto-fallback.c=412=static void blk_crypto_fallback_encrypt_bio(struct bio *src_bio)\n--\nblock/blk-crypto-fallback.c-423-\t}\nblock/blk-crypto-fallback.c:424:\t__blk_crypto_fallback_encrypt_bio(src_bio,\nblock/blk-crypto-fallback.c-425-\t\t\tblk_crypto_fallback_tfm(slot));\n"
}

gemini-3.1-pro-preview

null

null

							input: 8774
							output: 23
							thoughts: 19
						

Here's my thought process, as if I were analyzing that code:

**Analyzing the Callers of `blk_crypto_fallback_encrypt_bio`**

Okay, so I need to understand where `blk_crypto_fallback_encrypt_bio` is actually used. This function name strongly suggests it's a fallback encryption mechanism, likely within the block layer, and probably tied to some BIO (Buffered I/O) structure. That means it’s handling data moving in and out of block devices, potentially when hardware acceleration isn't available or configured. I want to see how the system is designed to handle this fallback, since it's an important performance consideration, and might hint at where acceleration is expected. I’ll start by tracing its calls to get a grasp of its role within the larger I/O flow. Time to start digging into the call graph!

{
  "Expression": "blk_crypto_fallback_encrypt_bio"
}

{
  "Output": "block/blk-crypto-fallback.c=253=static void blk_crypto_dun_to_iv(const u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE],\n--\nblock/blk-crypto-fallback.c-261-\nblock/blk-crypto-fallback.c:262:static void blk_crypto_fallback_encrypt_bio(struct bio *src_bio);\nblock/blk-crypto-fallback.c-263-\n--\nblock/blk-crypto-fallback.c=265=static void blk_crypto_fallback_encrypt_work_fn(struct work_struct *work)\n--\nblock/blk-crypto-fallback.c-277-\twhile ((src_bio = bio_list_pop(\u0026list)))\nblock/blk-crypto-fallback.c:278:\t\tblk_crypto_fallback_encrypt_bio(src_bio);\nblock/blk-crypto-fallback.c-279-}\nblock/blk-crypto-fallback.c-280-\nblock/blk-crypto-fallback.c:281:static void __blk_crypto_fallback_encrypt_bio(struct bio *src_bio,\nblock/blk-crypto-fallback.c-282-\t\tstruct crypto_sync_skcipher *tfm)\n--\nblock/blk-crypto-fallback.c-411- */\nblock/blk-crypto-fallback.c:412:static void blk_crypto_fallback_encrypt_bio(struct bio *src_bio)\nblock/blk-crypto-fallback.c-413-{\n--\nblock/blk-crypto-fallback.c-423-\t}\nblock/blk-crypto-fallback.c:424:\t__blk_crypto_fallback_encrypt_bio(src_bio,\nblock/blk-crypto-fallback.c-425-\t\t\tblk_crypto_fallback_tfm(slot));\n--\nblock/blk-crypto-fallback.c=544=bool blk_crypto_fallback_bio_prep(struct bio *bio)\n--\nblock/blk-crypto-fallback.c-561-\tif (bio_data_dir(bio) == WRITE) {\nblock/blk-crypto-fallback.c:562:\t\tblk_crypto_fallback_encrypt_bio(bio);\nblock/blk-crypto-fallback.c-563-\t\treturn false;\n"
}

gemini-3.1-pro-preview

null

null

							input: 9572
							output: 23
							thoughts: 33
						

Okay, let's dive into this. Here's how I'm thinking about it:

**Analyzing the Entry Point: `blk_crypto_fallback_bio_prep`**

Right, so `blk_crypto_fallback_bio_prep` is the designated entry point for this whole process. That's the starting gun, the first place execution hits. Now, the next logical step is to really dig into `blk_crypto_fallback_bio_prep` itself. I need to understand exactly what it does, the parameters it uses, and how it handles the initial setup. I want to see how it interfaces with the underlying block device and crypto functions. Understanding the role of the fallback here is crucial. What is this function a "fallback" *from*? And, if so, which other function?

{
  "Expression": "blk_crypto_fallback_bio_prep"
}

{
  "Output": "block/blk-crypto-fallback.c=507=static void blk_crypto_fallback_decrypt_endio(struct bio *bio)\n--\nblock/blk-crypto-fallback.c-526-/**\nblock/blk-crypto-fallback.c:527: * blk_crypto_fallback_bio_prep - Prepare a bio to use fallback en/decryption\nblock/blk-crypto-fallback.c-528- * @bio: bio to prepare\n--\nblock/blk-crypto-fallback.c-543- */\nblock/blk-crypto-fallback.c:544:bool blk_crypto_fallback_bio_prep(struct bio *bio)\nblock/blk-crypto-fallback.c-545-{\n--\nblock/blk-crypto-internal.h=213=static inline int blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,\n--\nblock/blk-crypto-internal.h-220-\nblock/blk-crypto-internal.h:221:bool blk_crypto_fallback_bio_prep(struct bio *bio);\nblock/blk-crypto-internal.h-222-\n--\nblock/blk-crypto.c=252=bool __blk_crypto_submit_bio(struct bio *bio)\n--\nblock/blk-crypto.c-273-\t\t}\nblock/blk-crypto.c:274:\t\treturn blk_crypto_fallback_bio_prep(bio);\nblock/blk-crypto.c-275-\t}\n"
}

gemini-3.1-pro-preview

null

null

							input: 10181
							output: 24
							thoughts: 322
						

**Analyzing Block Crypto Patch for Potential Vulnerabilities**

Okay, so I'm looking at this patch and my initial thought is that `__blk_crypto_submit_bio` is the main entry point for block crypto operations. The patch seems to be modifying some key functions: `blk_crypto_alloc_enc_bio`, `blk_crypto_fallback_encrypt_work_fn`, and `mempool_alloc_bulk_noprof`.

Let me quickly verify if `mempool_alloc_bulk_noprof` is even visible externally. Ah, yep, it's `EXPORT_SYMBOL_GPL`'d, so it's a legitimate target for investigation. Given that, `blk_crypto_fallback_bio_prep` and `blk_crypto_fallback_encrypt_work_fn` are also worth a look.

Wait a second, I see the core issue – this is designed to prevent deadlocks during recursive bio submissions by shifting operations to a workqueue. Okay, that context is essential. The `blk_crypto_fallback_encrypt_work_fn` is definitely a new function introduced by this patch. This is a prime candidate for fuzzing given its new nature. The patch also modifies `mempool_alloc_bulk_noprof` to account for `gfp_mask` and handle `__GFP_DIRECT_RECLAIM` which could have interesting consequences.

Now, let's get down to brass tacks: what's the necessary configuration to trigger this behavior? It looks like we need `BLK_INLINE_ENCRYPTION_FALLBACK`. Does it have any upstream dependencies that could impact its function? Alright, it depends on `BLK_INLINE_ENCRYPTION`. Time to check the dependencies for `BLK_INLINE_ENCRYPTION`.

{
  "Expression": "config BLK_INLINE_ENCRYPTION"
}

{
  "Output": "block/Kconfig=185=config BLK_SED_OPAL\n--\nblock/Kconfig-194-\nblock/Kconfig:195:config BLK_INLINE_ENCRYPTION\nblock/Kconfig-196-\tbool \"Enable inline encryption support in block layer\"\n--\nblock/Kconfig-201-\nblock/Kconfig:202:config BLK_INLINE_ENCRYPTION_FALLBACK\nblock/Kconfig-203-\tbool \"Enable crypto API fallback for blk-crypto\"\n"
}

gemini-3.1-pro-preview

null

null

							input: 11052
							output: 32
							thoughts: 17
						

Here's a summary of my thought process:

**Reviewing `block/Kconfig`**

Okay, time to circle back to `block/Kconfig`. I need to refresh my memory on the specific configuration options around line 195. I recall we had discussed this section previously, and I want to re-evaluate it with fresh eyes, considering the latest discussions and potential implications. Let me go take a look at it...

{
  "File": "block/Kconfig",
  "FirstLine": 190,
  "LineCount": 20
}

{
  "Contents": " 190:\t\thelp\n 191:\t\tBuilds Logic for interfacing with Opal enabled controllers.\n 192:\t\tEnabling this option enables users to setup/unlock/lock\n 193:\t\tLocking ranges for SED devices using the Opal protocol.\n 194:\t\n 195:\tconfig BLK_INLINE_ENCRYPTION\n 196:\t\tbool \"Enable inline encryption support in block layer\"\n 197:\t\thelp\n 198:\t\t  Build the blk-crypto subsystem. Enabling this lets the\n 199:\t\t  block layer handle encryption, so users can take\n 200:\t\t  advantage of inline encryption hardware if present.\n 201:\t\n 202:\tconfig BLK_INLINE_ENCRYPTION_FALLBACK\n 203:\t\tbool \"Enable crypto API fallback for blk-crypto\"\n 204:\t\tdepends on BLK_INLINE_ENCRYPTION\n 205:\t\tselect CRYPTO\n 206:\t\tselect CRYPTO_SKCIPHER\n 207:\t\thelp\n 208:\t\t  Enabling this lets the block layer handle inline encryption\n 209:\t\t  by falling back to the kernel crypto API when inline\n"
}

gemini-3.1-pro-preview

null

null

							input: 11502
							output: 23
							thoughts: 273
						

**My Configuration Analysis and Fuzzing Strategy**

Okay, so I'm looking at these configurations. `BLK_INLINE_ENCRYPTION` is self-contained, no dependencies. But, `BLK_INLINE_ENCRYPTION_FALLBACK` builds upon that, right? Good. Just double-checking, and yep, `CONFIG_CRYPTO` and `CONFIG_CRYPTO_SKCIPHER` are selected as well.

So we have the two main configs: `BLK_INLINE_ENCRYPTION` and its fallback. Now, let's dive deeper. I'm wondering if `mempool_alloc_bulk_noprof` can be reached without the block crypto path. Ah, it *is* exported, but currently seems to be used only by the block crypto fallback. Hang on, that's a *core* memory management function! That's definitely worth some serious fuzzing attention.

Alright, the core focus then will be:

*   `mempool_alloc_bulk_noprof` - that's a priority.
*   `blk_crypto_fallback_encrypt_work_fn` - that's a good entry point.
*   `blk_crypto_alloc_enc_bio` - I'm noting this one, even though it's static. Let's include it in the initial coverage, or consider also its non-static equivalent `__blk_crypto_fallback_encrypt_bio`.

Wait a minute, `blk_crypto_alloc_enc_bio` is static, which means it might be inlined. I should double-check that; I'll need to verify whether it's actually inlined before I finalize the inclusion of this particular symbol.

{
  "Expression": "blk_crypto_alloc_enc_bio"
}

{
  "Output": "block/blk-crypto-fallback.c=148=static void blk_crypto_fallback_encrypt_endio(struct bio *enc_bio)\n--\nblock/blk-crypto-fallback.c-175-\nblock/blk-crypto-fallback.c:176:static struct bio *blk_crypto_alloc_enc_bio(struct bio *bio_src,\nblock/blk-crypto-fallback.c-177-\t\tunsigned int nr_segs, struct page ***pages_ret)\n--\nblock/blk-crypto-fallback.c=281=static void __blk_crypto_fallback_encrypt_bio(struct bio *src_bio,\n--\nblock/blk-crypto-fallback.c-313-\tnr_enc_pages = min(bio_segments(src_bio), BIO_MAX_VECS);\nblock/blk-crypto-fallback.c:314:\tenc_bio = blk_crypto_alloc_enc_bio(src_bio, nr_enc_pages, \u0026enc_pages);\nblock/blk-crypto-fallback.c-315-\tif (unlikely(!enc_bio)) {\n"
}

gemini-3.1-pro-preview

null

null

							input: 12450
							output: 35
							thoughts: 149
						

**Analyzing Cryptographic BIO Allocation**

Okay, so I'm looking at this `blk_crypto_alloc_enc_bio` function. It's marked as `static`, which is fine, but it's a pretty hefty chunk of code. I'm wondering if the compiler will actually inline it, given that it handles bio allocation and page allocation – that's often a bit too much for a simple inlining.

Then there's `__blk_crypto_fallback_encrypt_bio`, which is *also* static. Hmm. The real entry point is `blk_crypto_fallback_bio_prep`, and that one *isn't* static. Right, that's the one we want to focus on. I think we can leverage `blk_crypto_fallback_bio_prep`, along with `blk_crypto_fallback_encrypt_work_fn` and `mempool_alloc_bulk_noprof` to get the desired functionality.

Now, let's take a closer look at `mempool_alloc_bulk_noprof` because that's always good to understand the memory allocation strategy in detail. Time to check `mm/mempool.c`.

{
  "File": "mm/mempool.c",
  "FirstLine": 480,
  "LineCount": 20
}

{
  "Contents": " 480:\t *\t\tindefinitely until it succeeds and the return value is always\n 481:\t *\t\t%true.  If the mask doesn't include %__GFP_DIRECT_RECLAIM, then\n 482:\t *\t\tfailure is allowed and %false can be returned.\n 483:\t *\n 484:\t * Allocate @count elements into @elems.  This is done by first calling into the\n 485:\t * alloc_fn supplied at pool initialization time, and dipping into the reserved\n 486:\t * pool to atomically allocate the remaining elements if alloc_fn fails.\n 487:\t *\n 488:\t * Return: %true if the allocation succeeded, or %false if it failed.\n 489:\t */\n 490:\tbool mempool_alloc_bulk_noprof(struct mempool *pool, void **elems,\n 491:\t\t\tunsigned int count, gfp_t gfp_mask)\n 492:\t{\n 493:\t\tgfp_t gfp_temp = mempool_adjust_gfp(\u0026gfp_mask);\n 494:\t\tunsigned int allocated = 0;\n 495:\t\n 496:\t\tVM_WARN_ON_ONCE(count \u003e pool-\u003emin_nr);\n 497:\t\tVM_WARN_ON_ONCE(gfp_mask \u0026 __GFP_ZERO);\n 498:\t\tmight_alloc(gfp_mask);\n 499:\t\n"
}

gemini-3.1-pro-preview

null

null

							input: 13270
							output: 202
							thoughts: 219
						

**Fuzzing Strategy for Block Crypto Fallback**

Okay, so this patch is definitely worth a look for fuzzing. It's functional, meaning it actually changes how things *work*—and it touches some key areas, specifically the core memory management and the block crypto fallback logic, which is crucial for overall system integrity. The fact that it's reachable in virtualized environments makes it even more attractive for testing.

I'm flagging this as `WorthFuzzing=true`.

I'll be specifically targeting these symbols: `mempool_alloc_bulk_noprof`, `blk_crypto_fallback_encrypt_work_fn`, and `blk_crypto_fallback_bio_prep`. Focusing on these should help me understand the impact of the patch's changes and test the new logic.

I need to make sure the relevant configuration options are enabled, that would be `BLK_INLINE_ENCRYPTION` and `BLK_INLINE_ENCRYPTION_FALLBACK`.

The reasoning is pretty clear: This patch fundamentally alters how `mempool_alloc_bulk_noprof` behaves. It now takes a `gfp_mask` and handles allocation failures better. More importantly, it integrates this change into the `blk-crypto-fallback` subsystem. The introduction of the `enc_rescue_work` workqueue to avoid deadlocks during recursive bio submissions suggests a subtle but crucial fix. It's about punting encryption work when `current->bio_list` is non-null, which is a common scenario in block layer operations. That's a classic race condition fix! My guess is that the workqueue will introduce a new potential attack surface.

{
  "EnableConfigs": [
    "BLK_INLINE_ENCRYPTION",
    "BLK_INLINE_ENCRYPTION_FALLBACK"
  ],
  "FocusSymbols": [
    "mempool_alloc_bulk_noprof",
    "blk_crypto_fallback_encrypt_work_fn",
    "blk_crypto_fallback_bio_prep"
  ],
  "Reasoning": "The patch modifies `mempool_alloc_bulk_noprof` to accept a `gfp_mask` and handle allocation failures properly. It also updates `blk-crypto-fallback` to use this new signature and introduces a workqueue (`enc_rescue_work`) to prevent deadlocks during recursive bio submissions by punting encryption work when `current-\u003ebio_list` is non-null. This is a functional change in core memory management and block layer crypto fallback logic, which is reachable in virtualized environments.",
  "WorthFuzzing": true
}

{
  "EnableConfigs": [
    "BLK_INLINE_ENCRYPTION",
    "BLK_INLINE_ENCRYPTION_FALLBACK"
  ],
  "FocusSymbols": [
    "mempool_alloc_bulk_noprof",
    "blk_crypto_fallback_encrypt_work_fn",
    "blk_crypto_fallback_bio_prep"
  ],
  "Reasoning": "The patch modifies `mempool_alloc_bulk_noprof` to accept a `gfp_mask` and handle allocation failures properly. It also updates `blk-crypto-fallback` to use this new signature and introduces a workqueue (`enc_rescue_work`) to prevent deadlocks during recursive bio submissions by punting encryption work when `current-\u003ebio_list` is non-null. This is a functional change in core memory management and block layer crypto fallback logic, which is reachable in virtualized environments.",
  "WorthFuzzing": true
}