linux-kernel - arch/x86/include/uapi/../../../../lib/vdso/gettimeofday.c:308 __cvdso_clock_gettime_common() warn: right shifting more than type allows 32 vs 40

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <202602111941.PIhubgrb-lkp@intel.com>
Date: Wed, 11 Feb 2026 15:13:34 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: oe-kbuild@...ts.linux.dev, "H. Peter Anvin" <hpa@...or.com>
Cc: lkp@...el.com, oe-kbuild-all@...ts.linux.dev,
	linux-kernel@...r.kernel.org,
	Dave Hansen <dave.hansen@...ux.intel.com>
Subject: arch/x86/include/uapi/../../../../lib/vdso/gettimeofday.c:308
 __cvdso_clock_gettime_common() warn: right shifting more than type allows 32
 vs 40

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   192c0159402e6bfbe13de6f8379546943297783d
commit: 693c819fedcdcabfda7488e2d5e355a84c2fd1b0 x86/entry/vdso: Refactor the vdso build
config: x86_64-randconfig-161-20260210 (https://download.01.org/0day-ci/archive/20260211/202602111941.PIhubgrb-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
rustc: rustc 1.88.0 (6b00bc388 2025-06-23)
smatch version: v0.5.0-8994-gd50c5a4c

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@...el.com>
| Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
| Closes: https://lore.kernel.org/r/202602111941.PIhubgrb-lkp@intel.com/

smatch warnings:
arch/x86/include/uapi/../../../../lib/vdso/gettimeofday.c:308 __cvdso_clock_gettime_common() warn: right shifting more than type allows 32 vs 40
arch/x86/include/uapi/../../../../lib/vdso/gettimeofday.c:308 __cvdso_clock_gettime_common() warn: bitwise AND condition is false here
arch/x86/include/uapi/../../../../lib/vdso/gettimeofday.c:454 __cvdso_clock_getres_common() warn: right shifting more than type allows 32 vs 40
arch/x86/include/uapi/../../../../lib/vdso/gettimeofday.c:454 __cvdso_clock_getres_common() warn: bitwise AND condition is false here

vim +308 arch/x86/include/uapi/../../../../lib/vdso/gettimeofday.c

fb61bdb27fd730 Thomas Weißschuh   2025-07-01  287  static __always_inline bool
ac1a42f4e4e296 Thomas Weißschuh   2025-02-04  288  __cvdso_clock_gettime_common(const struct vdso_time_data *vd, clockid_t clock,
e876f0b69dc993 Christophe Leroy   2020-02-07  289  			     struct __kernel_timespec *ts)
00b26474c2f161 Vincenzo Frascino  2019-06-21  290  {
886653e3663917 Anna-Maria Behnsen 2025-03-03  291  	const struct vdso_clock *vc = vd->clock_data;
00b26474c2f161 Vincenzo Frascino  2019-06-21  292  	u32 msk;
00b26474c2f161 Vincenzo Frascino  2019-06-21  293  
1a1cd5fe881fdf Thomas Weißschuh   2025-07-01  294  	if (!vdso_clockid_valid(clock))
fb61bdb27fd730 Thomas Weißschuh   2025-07-01  295  		return false;
00b26474c2f161 Vincenzo Frascino  2019-06-21  296  
00b26474c2f161 Vincenzo Frascino  2019-06-21  297  	/*
00b26474c2f161 Vincenzo Frascino  2019-06-21  298  	 * Convert the clockid to a bitmask and use it to check which
00b26474c2f161 Vincenzo Frascino  2019-06-21  299  	 * clocks are handled in the VDSO directly.
00b26474c2f161 Vincenzo Frascino  2019-06-21  300  	 */
00b26474c2f161 Vincenzo Frascino  2019-06-21  301  	msk = 1U << clock;
8463cf80529d0f Christophe Leroy   2019-12-23  302  	if (likely(msk & VDSO_HRES))
cddb82d1c4de56 Anna-Maria Behnsen 2025-03-03  303  		vc = &vc[CS_HRES_COARSE];
8463cf80529d0f Christophe Leroy   2019-12-23  304  	else if (msk & VDSO_COARSE)
70067ae181f302 Anna-Maria Behnsen 2025-03-03  305  		return do_coarse(vd, &vc[CS_HRES_COARSE], clock, ts);
8463cf80529d0f Christophe Leroy   2019-12-23  306  	else if (msk & VDSO_RAW)
cddb82d1c4de56 Anna-Maria Behnsen 2025-03-03  307  		vc = &vc[CS_RAW];
cd3557a7618bf5 Thomas Weißschuh   2025-07-01 @308  	else if (msk & VDSO_AUX)

This code is built with -m32 when we build
arch/x86/entry/vdso/vdso32/vclock_gettime.c so VDSO_AUX is zero
and we never call do_aux().  Presumably that's intentional.  I
don't know this code at all.

cd3557a7618bf5 Thomas Weißschuh   2025-07-01  309  		return do_aux(vd, clock, ts);
c966533f8c6c45 Andrei Vagin       2019-11-12  310  	else
fb61bdb27fd730 Thomas Weißschuh   2025-07-01  311  		return false;
c966533f8c6c45 Andrei Vagin       2019-11-12  312  
64c3613ce31a1a Anna-Maria Behnsen 2025-03-03  313  	return do_hres(vd, vc, clock, ts);
502a590a170b3b Thomas Gleixner    2019-07-28  314  }