[PATCH v4 2/6] treewide: use prandom_u32_max() when possible

From: Jason A. Donenfeld
Date: Fri Oct 07 2022 - 14:03:15 EST

Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions.

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: KP Singh <kpsingh@xxxxxxxxxx>
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@xxxxxxxxxx> # for drbd
Reviewed-by: Jan Kara <jack@xxxxxxx> # for ext2, ext4, and sbitmap
Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
---
arch/arm64/kernel/process.c | 2 +-
arch/loongarch/kernel/process.c | 2 +-
arch/loongarch/kernel/vdso.c | 2 +-
arch/mips/kernel/process.c | 2 +-
arch/mips/kernel/vdso.c | 2 +-
arch/parisc/kernel/vdso.c | 2 +-
arch/powerpc/kernel/process.c | 2 +-
arch/s390/kernel/process.c | 2 +-
drivers/block/drbd/drbd_receiver.c | 4 ++--
drivers/md/bcache/request.c | 2 +-
drivers/mtd/tests/stresstest.c | 17 ++++-------------
drivers/mtd/ubi/debug.h | 6 +++---
drivers/net/ethernet/broadcom/cnic.c | 3 +--
fs/ext2/ialloc.c | 3 +--
fs/ext4/ialloc.c | 5 ++---
fs/ubifs/lpt_commit.c | 2 +-
fs/ubifs/tnc_commit.c | 2 +-
fs/xfs/libxfs/xfs_alloc.c | 2 +-
fs/xfs/libxfs/xfs_ialloc.c | 2 +-
include/linux/nodemask.h | 2 +-
lib/cmdline_kunit.c | 4 ++--
lib/kobject.c | 2 +-
lib/reed_solomon/test_rslib.c | 2 +-
lib/sbitmap.c | 2 +-
lib/test_hexdump.c | 2 +-
lib/test_vmalloc.c | 17 ++++-------------
net/core/pktgen.c | 4 ++--
net/ipv4/inet_hashtables.c | 2 +-
net/sunrpc/cache.c | 2 +-
net/sunrpc/xprtsock.c | 2 +-
30 files changed, 42 insertions(+), 63 deletions(-)

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 92bcc1768f0b..87203429f802 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -595,7 +595,7 @@ unsigned long __get_wchan(struct task_struct *p)
unsigned long arch_align_stack(unsigned long sp)
{
if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
- sp -= get_random_int() & ~PAGE_MASK;
+ sp -= prandom_u32_max(PAGE_SIZE);
return sp & ~0xf;
}

diff --git a/arch/loongarch/kernel/process.c b/arch/loongarch/kernel/process.c
index 660492f064e7..1256e3582475 100644
--- a/arch/loongarch/kernel/process.c
+++ b/arch/loongarch/kernel/process.c
@@ -293,7 +293,7 @@ unsigned long stack_top(void)
unsigned long arch_align_stack(unsigned long sp)
{
if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
- sp -= get_random_int() & ~PAGE_MASK;
+ sp -= prandom_u32_max(PAGE_SIZE);

return sp & STACK_ALIGN;
}
diff --git a/arch/loongarch/kernel/vdso.c b/arch/loongarch/kernel/vdso.c
index f32c38abd791..8c9826062652 100644
--- a/arch/loongarch/kernel/vdso.c
+++ b/arch/loongarch/kernel/vdso.c
@@ -78,7 +78,7 @@ static unsigned long vdso_base(void)
unsigned long base = STACK_TOP;

if (current->flags & PF_RANDOMIZE) {
- base += get_random_int() & (VDSO_RANDOMIZE_SIZE - 1);
+ base += prandom_u32_max(VDSO_RANDOMIZE_SIZE);
base = PAGE_ALIGN(base);
}

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 35b912bce429..bbe9ce471791 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -711,7 +711,7 @@ unsigned long mips_stack_top(void)
unsigned long arch_align_stack(unsigned long sp)
{
if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
- sp -= get_random_int() & ~PAGE_MASK;
+ sp -= prandom_u32_max(PAGE_SIZE);

return sp & ALMASK;
}
diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c
index b2cc2c2dd4bf..5fd9bf1d596c 100644
--- a/arch/mips/kernel/vdso.c
+++ b/arch/mips/kernel/vdso.c
@@ -79,7 +79,7 @@ static unsigned long vdso_base(void)
}

if (current->flags & PF_RANDOMIZE) {
- base += get_random_int() & (VDSO_RANDOMIZE_SIZE - 1);
+ base += prandom_u32_max(VDSO_RANDOMIZE_SIZE);
base = PAGE_ALIGN(base);
}

diff --git a/arch/parisc/kernel/vdso.c b/arch/parisc/kernel/vdso.c
index 63dc44c4c246..47e5960a2f96 100644
--- a/arch/parisc/kernel/vdso.c
+++ b/arch/parisc/kernel/vdso.c
@@ -75,7 +75,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm,

map_base = mm->mmap_base;
if (current->flags & PF_RANDOMIZE)
- map_base -= (get_random_int() & 0x1f) * PAGE_SIZE;
+ map_base -= prandom_u32_max(0x20) * PAGE_SIZE;

vdso_text_start = get_unmapped_area(NULL, map_base, vdso_text_len, 0, 0);

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 0fbda89cd1bb..ff920f4d4317 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -2308,6 +2308,6 @@ void notrace __ppc64_runlatch_off(void)
unsigned long arch_align_stack(unsigned long sp)
{
if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
- sp -= get_random_int() & ~PAGE_MASK;
+ sp -= prandom_u32_max(PAGE_SIZE);
return sp & ~0xf;
}
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index d5119e039d85..5ec78555dd2e 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -224,7 +224,7 @@ unsigned long __get_wchan(struct task_struct *p)
unsigned long arch_align_stack(unsigned long sp)
{
if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
- sp -= get_random_int() & ~PAGE_MASK;
+ sp -= prandom_u32_max(PAGE_SIZE);
return sp & ~0xf;
}

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index af4c7d65490b..d8b1417dc503 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -781,7 +781,7 @@ static struct socket *drbd_wait_for_connect(struct drbd_connection *connection,

timeo = connect_int * HZ;
/* 28.5% random jitter */
- timeo += (prandom_u32() & 1) ? timeo / 7 : -timeo / 7;
+ timeo += prandom_u32_max(2) ? timeo / 7 : -timeo / 7;

err = wait_for_completion_interruptible_timeout(&ad->door_bell, timeo);
if (err <= 0)
@@ -1004,7 +1004,7 @@ static int conn_connect(struct drbd_connection *connection)
drbd_warn(connection, "Error receiving initial packet\n");
sock_release(s);
randomize:
- if (prandom_u32() & 1)
+ if (prandom_u32_max(2))
goto retry;
}
}
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index f2c5a7e06fa9..3427555b0cca 100644
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -401,7 +401,7 @@ static bool check_should_bypass(struct cached_dev *dc, struct bio *bio)
}

if (bypass_torture_test(dc)) {
- if ((get_random_int() & 3) == 3)
+ if (prandom_u32_max(4) == 3)
goto skip;
else
goto rescale;
diff --git a/drivers/mtd/tests/stresstest.c b/drivers/mtd/tests/stresstest.c
index cb29c8c1b370..d2faaca7f19d 100644
--- a/drivers/mtd/tests/stresstest.c
+++ b/drivers/mtd/tests/stresstest.c
@@ -45,9 +45,8 @@ static int rand_eb(void)
unsigned int eb;

again:
- eb = prandom_u32();
/* Read or write up 2 eraseblocks at a time - hence 'ebcnt - 1' */
- eb %= (ebcnt - 1);
+ eb = prandom_u32_max(ebcnt - 1);
if (bbt[eb])
goto again;
return eb;
@@ -55,20 +54,12 @@ static int rand_eb(void)

static int rand_offs(void)
{
- unsigned int offs;
-
- offs = prandom_u32();
- offs %= bufsize;
- return offs;
+ return prandom_u32_max(bufsize);
}

static int rand_len(int offs)
{
- unsigned int len;
-
- len = prandom_u32();
- len %= (bufsize - offs);
- return len;
+ return prandom_u32_max(bufsize - offs);
}

static int do_read(void)
@@ -127,7 +118,7 @@ static int do_write(void)

static int do_operation(void)
{
- if (prandom_u32() & 1)
+ if (prandom_u32_max(2))
return do_read();
else
return do_write();
diff --git a/drivers/mtd/ubi/debug.h b/drivers/mtd/ubi/debug.h
index 118248a5d7d4..dc8d8f83657a 100644
--- a/drivers/mtd/ubi/debug.h
+++ b/drivers/mtd/ubi/debug.h
@@ -73,7 +73,7 @@ static inline int ubi_dbg_is_bgt_disabled(const struct ubi_device *ubi)
static inline int ubi_dbg_is_bitflip(const struct ubi_device *ubi)
{
if (ubi->dbg.emulate_bitflips)
- return !(prandom_u32() % 200);
+ return !prandom_u32_max(200);
return 0;
}

@@ -87,7 +87,7 @@ static inline int ubi_dbg_is_bitflip(const struct ubi_device *ubi)
static inline int ubi_dbg_is_write_failure(const struct ubi_device *ubi)
{
if (ubi->dbg.emulate_io_failures)
- return !(prandom_u32() % 500);
+ return !prandom_u32_max(500);
return 0;
}

@@ -101,7 +101,7 @@ static inline int ubi_dbg_is_write_failure(const struct ubi_device *ubi)
static inline int ubi_dbg_is_erase_failure(const struct ubi_device *ubi)
{
if (ubi->dbg.emulate_io_failures)
- return !(prandom_u32() % 400);
+ return !prandom_u32_max(400);
return 0;
}

diff --git a/drivers/net/ethernet/broadcom/cnic.c b/drivers/net/ethernet/broadcom/cnic.c
index e86503d97f32..f597b313acaa 100644
--- a/drivers/net/ethernet/broadcom/cnic.c
+++ b/drivers/net/ethernet/broadcom/cnic.c
@@ -4105,8 +4105,7 @@ static int cnic_cm_alloc_mem(struct cnic_dev *dev)
for (i = 0; i < MAX_CM_SK_TBL_SZ; i++)
atomic_set(&cp->csk_tbl[i].ref_count, 0);

- port_id = prandom_u32();
- port_id %= CNIC_LOCAL_PORT_RANGE;
+ port_id = prandom_u32_max(CNIC_LOCAL_PORT_RANGE);
if (cnic_init_id_tbl(&cp->csk_port_tbl, CNIC_LOCAL_PORT_RANGE,
CNIC_LOCAL_PORT_MIN, port_id)) {
cnic_cm_free_mem(dev);
diff --git a/fs/ext2/ialloc.c b/fs/ext2/ialloc.c
index 998dd2ac8008..f4944c4dee60 100644
--- a/fs/ext2/ialloc.c
+++ b/fs/ext2/ialloc.c
@@ -277,8 +277,7 @@ static int find_group_orlov(struct super_block *sb, struct inode *parent)
int best_ndir = inodes_per_group;
int best_group = -1;

- group = prandom_u32();
- parent_group = (unsigned)group % ngroups;
+ parent_group = prandom_u32_max(ngroups);
for (i = 0; i < ngroups; i++) {
group = (parent_group + i) % ngroups;
desc = ext2_get_group_desc (sb, group, NULL);
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index f73e5eb43eae..36d5bc595cc2 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -463,10 +463,9 @@ static int find_group_orlov(struct super_block *sb, struct inode *parent,
hinfo.hash_version = DX_HASH_HALF_MD4;
hinfo.seed = sbi->s_hash_seed;
ext4fs_dirhash(parent, qstr->name, qstr->len, &hinfo);
- grp = hinfo.hash;
+ parent_group = hinfo.hash % ngroups;
} else
- grp = prandom_u32();
- parent_group = (unsigned)grp % ngroups;
+ parent_group = prandom_u32_max(ngroups);
for (i = 0; i < ngroups; i++) {
g = (parent_group + i) % ngroups;
get_orlov_stats(sb, g, flex_size, &stats);
diff --git a/fs/ubifs/lpt_commit.c b/fs/ubifs/lpt_commit.c
index cd4d5726a78d..cfbc31f709f4 100644
--- a/fs/ubifs/lpt_commit.c
+++ b/fs/ubifs/lpt_commit.c
@@ -1970,7 +1970,7 @@ static int dbg_populate_lsave(struct ubifs_info *c)

if (!dbg_is_chk_gen(c))
return 0;
- if (prandom_u32() & 3)
+ if (prandom_u32_max(4))
return 0;

for (i = 0; i < c->lsave_cnt; i++)
diff --git a/fs/ubifs/tnc_commit.c b/fs/ubifs/tnc_commit.c
index 58c92c96ecef..01362ad5f804 100644
--- a/fs/ubifs/tnc_commit.c
+++ b/fs/ubifs/tnc_commit.c
@@ -700,7 +700,7 @@ static int alloc_idx_lebs(struct ubifs_info *c, int cnt)
c->ilebs[c->ileb_cnt++] = lnum;
dbg_cmt("LEB %d", lnum);
}
- if (dbg_is_chk_index(c) && !(prandom_u32() & 7))
+ if (dbg_is_chk_index(c) && !prandom_u32_max(8))
return -ENOSPC;
return 0;
}
diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index e2bdf089c0a3..6261599bb389 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -1520,7 +1520,7 @@ xfs_alloc_ag_vextent_lastblock(

#ifdef DEBUG
/* Randomly don't execute the first algorithm. */
- if (prandom_u32() & 1)
+ if (prandom_u32_max(2))
return 0;
#endif

diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
index 6cdfd64bc56b..7838b31126e2 100644
--- a/fs/xfs/libxfs/xfs_ialloc.c
+++ b/fs/xfs/libxfs/xfs_ialloc.c
@@ -636,7 +636,7 @@ xfs_ialloc_ag_alloc(
/* randomly do sparse inode allocations */
if (xfs_has_sparseinodes(tp->t_mountp) &&
igeo->ialloc_min_blks < igeo->ialloc_blks)
- do_sparse = prandom_u32() & 1;
+ do_sparse = prandom_u32_max(2);
#endif

/*
diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h
index 4b71a96190a8..66ee9b4b7925 100644
--- a/include/linux/nodemask.h
+++ b/include/linux/nodemask.h
@@ -509,7 +509,7 @@ static inline int node_random(const nodemask_t *maskp)
w = nodes_weight(*maskp);
if (w)
bit = bitmap_ord_to_pos(maskp->bits,
- get_random_int() % w, MAX_NUMNODES);
+ prandom_u32_max(w), MAX_NUMNODES);
return bit;
#else
return 0;
diff --git a/lib/cmdline_kunit.c b/lib/cmdline_kunit.c
index e6a31c927b06..a72a2c16066e 100644
--- a/lib/cmdline_kunit.c
+++ b/lib/cmdline_kunit.c
@@ -76,7 +76,7 @@ static void cmdline_test_lead_int(struct kunit *test)
int rc = cmdline_test_values[i];
int offset;

- sprintf(in, "%u%s", prandom_u32_max(256), str);
+ sprintf(in, "%u%s", get_random_int() % 256, str);
/* Only first '-' after the number will advance the pointer */
offset = strlen(in) - strlen(str) + !!(rc == 2);
cmdline_do_one_test(test, in, rc, offset);
@@ -94,7 +94,7 @@ static void cmdline_test_tail_int(struct kunit *test)
int rc = strcmp(str, "") ? (strcmp(str, "-") ? 0 : 1) : 1;
int offset;

- sprintf(in, "%s%u", str, prandom_u32_max(256));
+ sprintf(in, "%s%u", str, get_random_int() % 256);
/*
* Only first and leading '-' not followed by integer
* will advance the pointer.
diff --git a/lib/kobject.c b/lib/kobject.c
index 5f0e71ab292c..a0b2dbfcfa23 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -694,7 +694,7 @@ static void kobject_release(struct kref *kref)
{
struct kobject *kobj = container_of(kref, struct kobject, kref);
#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
- unsigned long delay = HZ + HZ * (get_random_int() & 0x3);
+ unsigned long delay = HZ + HZ * prandom_u32_max(4);
pr_info("kobject: '%s' (%p): %s, parent %p (delayed %ld)\n",
kobject_name(kobj), kobj, __func__, kobj->parent, delay);
INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
diff --git a/lib/reed_solomon/test_rslib.c b/lib/reed_solomon/test_rslib.c
index 6faf9c9a6215..4d241bdc88aa 100644
--- a/lib/reed_solomon/test_rslib.c
+++ b/lib/reed_solomon/test_rslib.c
@@ -199,7 +199,7 @@ static int get_rcw_we(struct rs_control *rs, struct wspace *ws,

derrlocs[i] = errloc;

- if (ewsc && (prandom_u32() & 1)) {
+ if (ewsc && prandom_u32_max(2)) {
/* Erasure with the symbol intact */
errlocs[errloc] = 2;
} else {
diff --git a/lib/sbitmap.c b/lib/sbitmap.c
index c4f04edf3ee9..ef0661504561 100644
--- a/lib/sbitmap.c
+++ b/lib/sbitmap.c
@@ -21,7 +21,7 @@ static int init_alloc_hint(struct sbitmap *sb, gfp_t flags)
int i;

for_each_possible_cpu(i)
- *per_cpu_ptr(sb->alloc_hint, i) = prandom_u32() % depth;
+ *per_cpu_ptr(sb->alloc_hint, i) = prandom_u32_max(depth);
}
return 0;
}
diff --git a/lib/test_hexdump.c b/lib/test_hexdump.c
index 0927f44cd478..41a0321f641a 100644
--- a/lib/test_hexdump.c
+++ b/lib/test_hexdump.c
@@ -208,7 +208,7 @@ static void __init test_hexdump_overflow(size_t buflen, size_t len,
static void __init test_hexdump_overflow_set(size_t buflen, bool ascii)
{
unsigned int i = 0;
- int rs = (prandom_u32_max(2) + 1) * 16;
+ int rs = prandom_u32_max(2) + 1 * 16;

do {
int gs = 1 << i;
diff --git a/lib/test_vmalloc.c b/lib/test_vmalloc.c
index 4f2f2d1bac56..56ffaa8dd3f6 100644
--- a/lib/test_vmalloc.c
+++ b/lib/test_vmalloc.c
@@ -151,9 +151,7 @@ static int random_size_alloc_test(void)
int i;

for (i = 0; i < test_loop_count; i++) {
- n = prandom_u32();
- n = (n % 100) + 1;
-
+ n = prandom_u32_max(n % 100) + 1;
p = vmalloc(n * PAGE_SIZE);

if (!p)
@@ -293,16 +291,12 @@ pcpu_alloc_test(void)
return -1;

for (i = 0; i < 35000; i++) {
- unsigned int r;
-
- r = prandom_u32();
- size = (r % (PAGE_SIZE / 4)) + 1;
+ size = prandom_u32_max(PAGE_SIZE / 4) + 1;

/*
* Maximum PAGE_SIZE
*/
- r = prandom_u32();
- align = 1 << ((r % 11) + 1);
+ align = 1 << (prandom_u32_max(11) + 1);

pcpu[i] = __alloc_percpu(size, align);
if (!pcpu[i])
@@ -393,14 +387,11 @@ static struct test_driver {

static void shuffle_array(int *arr, int n)
{
- unsigned int rnd;
int i, j;

for (i = n - 1; i > 0; i--) {
- rnd = prandom_u32();
-
/* Cut the range. */
- j = rnd % i;
+ j = prandom_u32_max(i);

/* Swap indexes. */
swap(arr[i], arr[j]);
diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index a13ee452429e..5ca4f953034c 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -2469,11 +2469,11 @@ static void mod_cur_headers(struct pktgen_dev *pkt_dev)
}

if ((pkt_dev->flags & F_VID_RND) && (pkt_dev->vlan_id != 0xffff)) {
- pkt_dev->vlan_id = prandom_u32() & (4096 - 1);
+ pkt_dev->vlan_id = prandom_u32_max(4096);
}

if ((pkt_dev->flags & F_SVID_RND) && (pkt_dev->svlan_id != 0xffff)) {
- pkt_dev->svlan_id = prandom_u32() & (4096 - 1);
+ pkt_dev->svlan_id = prandom_u32_max(4096);
}

if (pkt_dev->udp_src_min < pkt_dev->udp_src_max) {
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index b9d995b5ce24..9dc070f2018e 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -794,7 +794,7 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row,
* on low contention the randomness is maximal and on high contention
* it may be inexistent.
*/
- i = max_t(int, i, (prandom_u32() & 7) * 2);
+ i = max_t(int, i, prandom_u32_max(8) * 2);
WRITE_ONCE(table_perturb[index], READ_ONCE(table_perturb[index]) + i + 2);

/* Head lock still held and bh's disabled */
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index c3c693b51c94..f075a9fb5ccc 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -677,7 +677,7 @@ static void cache_limit_defers(void)

/* Consider removing either the first or the last */
if (cache_defer_cnt > DFR_MAX) {
- if (prandom_u32() & 1)
+ if (prandom_u32_max(2))
discard = list_entry(cache_defer_list.next,
struct cache_deferred_req, recent);
else
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index e976007f4fd0..c2caee703d2c 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -1619,7 +1619,7 @@ static int xs_get_random_port(void)
if (max < min)
return -EADDRINUSE;
range = max - min + 1;
- rand = (unsigned short) prandom_u32() % range;
+ rand = (unsigned short) prandom_u32_max(range);
return rand + min;
}

--
2.37.3