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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Richard Fitzgerald <rf@opensource.cirrus.com>,
	kernel test robot <lkp@intel.com>, Petr Mladek <pmladek@suse.com>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 5.13 19/59] random32: Fix implicit truncation warning in prandom_seed_state()
Date: Mon,  5 Jul 2021 11:27:35 -0400	[thread overview]
Message-ID: <20210705152815.1520546-19-sashal@kernel.org> (raw)
In-Reply-To: <20210705152815.1520546-1-sashal@kernel.org>

From: Richard Fitzgerald <rf@opensource.cirrus.com>

[ Upstream commit d327ea15a305024ef0085252fa3657bbb1ce25f5 ]

sparse generates the following warning:

 include/linux/prandom.h:114:45: sparse: sparse: cast truncates bits from
 constant value

This is because the 64-bit seed value is manipulated and then placed in a
u32, causing an implicit cast and truncation. A forced cast to u32 doesn't
prevent this warning, which is reasonable because a typecast doesn't prove
that truncation was expected.

Logical-AND the value with 0xffffffff to make explicit that truncation to
32-bit is intended.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210525122012.6336-3-rf@opensource.cirrus.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/prandom.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/prandom.h b/include/linux/prandom.h
index bbf4b4ad61df..056d31317e49 100644
--- a/include/linux/prandom.h
+++ b/include/linux/prandom.h
@@ -111,7 +111,7 @@ static inline u32 __seed(u32 x, u32 m)
  */
 static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
 {
-	u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
+	u32 i = ((seed >> 32) ^ (seed << 10) ^ seed) & 0xffffffffUL;
 
 	state->s1 = __seed(i,   2U);
 	state->s2 = __seed(i,   8U);
-- 
2.30.2


  parent reply	other threads:[~2021-07-05 15:29 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-05 15:27 [PATCH AUTOSEL 5.13 01/59] HID: do not use down_interruptible() when unbinding devices Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 02/59] EDAC/ti: Add missing MODULE_DEVICE_TABLE Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 03/59] ACPI: PM: s2idle: Add missing LPS0 functions for AMD Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 04/59] ACPI: scan: Rearrange dep_unmet initialization Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 05/59] ACPI: processor idle: Fix up C-state latency if not ordered Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 06/59] hv_utils: Fix passing zero to 'PTR_ERR' warning Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 07/59] lib: vsprintf: Fix handling of number field widths in vsscanf Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 08/59] Input: goodix - platform/x86: touchscreen_dmi - Move upside down quirks to touchscreen_dmi.c Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 09/59] platform/x86: touchscreen_dmi: Add an extra entry for the upside down Goodix touchscreen on Teclast X89 tablets Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 10/59] platform/x86: touchscreen_dmi: Add info for the Goodix GT912 panel of TM800A550L tablets Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 11/59] ACPI: EC: Make more Asus laptops use ECDT _GPE Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 12/59] block_dump: remove block_dump feature in mark_inode_dirty() Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 13/59] blk-mq: grab rq->refcount before calling ->fn in blk_mq_tagset_busy_iter Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 14/59] blk-mq: clear stale request in tags->rq[] before freeing one request pool Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 15/59] fs: dlm: fix srcu read lock usage Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 16/59] fs: dlm: reconnect if socket error report occurs Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 17/59] fs: dlm: cancel work sync othercon Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 18/59] fs: dlm: fix connection tcp EOF handling Sasha Levin
2021-07-05 15:27 ` Sasha Levin [this message]
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 20/59] open: don't silently ignore unknown O-flags in openat2() Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 21/59] drivers: hv: Fix missing error code in vmbus_connect() Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 22/59] fs: dlm: fix lowcomms_start error case Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 23/59] fs: dlm: fix memory leak when fenced Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 24/59] ACPICA: Fix memory leak caused by _CID repair function Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 25/59] ACPI: bus: Call kobject_put() in acpi_init() error path Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 26/59] ACPI: resources: Add checks for ACPI IRQ override Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 27/59] HID: hid-input: add Surface Go battery quirk Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 28/59] HID: sony: fix freeze when inserting ghlive ps3/wii dongles Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 29/59] block: fix race between adding/removing rq qos and normal IO Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 30/59] platform/x86: asus-nb-wmi: Revert "Drop duplicate DMI quirk structures" Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 31/59] platform/x86: asus-nb-wmi: Revert "add support for ASUS ROG Zephyrus G14 and G15" Sasha Levin
2021-07-05 17:08   ` Hans de Goede
2021-07-05 17:09     ` Hans de Goede
2021-07-09 22:50       ` Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 32/59] platform/x86: toshiba_acpi: Fix missing error code in toshiba_acpi_setup_keyboard() Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 33/59] nvme-pci: fix var. type for increasing cq_head Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 34/59] nvmet-fc: do not check for invalid target port in nvmet_fc_handle_fcp_rqst() Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 35/59] EDAC/Intel: Do not load EDAC driver when running as a guest Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 36/59] tools/power/x86/intel-speed-select: Fix uncore memory frequency display Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 37/59] PCI: hv: Add check for hyperv_initialized in init_hv_pci_drv() Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 38/59] cifs: improve fallocate emulation Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 39/59] cifs: fix check of dfs interlinks Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 40/59] cifs: retry lookup and readdir when EAGAIN is returned Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 41/59] smb3: fix uninitialized value for port in witness protocol move Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 42/59] cifs: fix SMB1 error path in cifs_get_file_info_unix Sasha Levin

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