From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 346381FECCD for ; Sun, 8 Mar 2026 09:32:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772962354; cv=none; b=b9fEcE+AfonURMZPLsXx+UqF7Oj6oDSF5SGLlzmbH59A59RRmDuLWJwYuLz+7NGcWybqTTwZmG/in4QdxLsuyuSsWN9wqYe2F4WvkoPjFZFHKxxQ4R0gFU30ccRZsSUm4ZbIAqD85zCzCTnpSU7nlR6BRYR9aHo5R5iEHyJfu2g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772962354; c=relaxed/simple; bh=YiZLkAPKoYwrY58iPUmvFDQc8veTsJgLSl9THV9PCrE=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=uHvApLUgrxrpBMnybxwAzNg60lAUocMhnUc7YY603RbjH/D473cCT2SDoL29wYAKJw2cr6YfTmSx6DIDArjfr1XyaY/QlAmEy1op1EGxk+bnSBro7oam5BiPB0Kkj3i41tiUPk75yxvy/XP3ZGrMqzOKjfI0BRbeirEQRsYKJIg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Q/IppdUS; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Q/IppdUS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DCC27C116C6; Sun, 8 Mar 2026 09:32:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772962353; bh=YiZLkAPKoYwrY58iPUmvFDQc8veTsJgLSl9THV9PCrE=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=Q/IppdUSlxjYeikh3b7dIBjF+AUoTGf8TTu/kpCyLh8AkfiFSaDDXISTzluUGmVeA 0223D197Y0vJ3VuC2K426uChZIZgXpnlyEJ/DcyTuYcPYYzCuG26gDaq4DaJQ+p8hd i+Dj+FJISt6GxYMAKlgyngoTLcTTHexbAxBAVquioUHWoH8ICPFfEAoSXlBGwssB0e /efvrYmotLNDF/GWAaewM1W4uP0T7nxZs/K/xHUAjTr0D1xIcv9BBYQUFCXJAIElac NZqpm0kJZ60AL2nGEl3FxQSaGpLBAuQ9fcvhvfQeB+fi5j1mI0Y9c30yQ8wPgz3x1+ hq4ujekwaeKOQ== From: Thomas Gleixner To: syzbot , jstultz@google.com, linux-kernel@vger.kernel.org, sboyd@kernel.org, syzkaller-bugs@googlegroups.com Cc: Alexander Potapenko , Marco Elver , kasan-dev@googlegroups.com Subject: Re: [syzbot] [kernel?] KMSAN: uninit-value in timespec64_add_safe In-Reply-To: <69aa4169.050a0220.13f275.0007.GAE@google.com> References: <69aa4169.050a0220.13f275.0007.GAE@google.com> Date: Sun, 08 Mar 2026 10:32:30 +0100 Message-ID: <874imq3bv5.ffs@tglx> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Thu, Mar 05 2026 at 18:52, syzbot wrote: > udevd[5131]: starting eudev-3.2.14 > ===================================================== > BUG: KMSAN: uninit-value in set_normalized_timespec64 kernel/time/time.c:492 [inline] > BUG: KMSAN: uninit-value in timespec64_add_safe+0x4b4/0x520 kernel/time/time.c:846 > set_normalized_timespec64 kernel/time/time.c:492 [inline] > timespec64_add_safe+0x4b4/0x520 kernel/time/time.c:846 > ep_timeout_to_timespec fs/eventpoll.c:1872 [inline] > __do_sys_epoll_wait fs/eventpoll.c:2471 [inline] > __se_sys_epoll_wait fs/eventpoll.c:2465 [inline] > __x64_sys_epoll_wait+0x1fa/0x3a0 fs/eventpoll.c:2465 > x64_sys_call+0x2ece/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:233 > do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] > do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > Local variable now.i.i.i created at: > ep_timeout_to_timespec fs/eventpoll.c:1857 [inline] > __do_sys_epoll_wait fs/eventpoll.c:2471 [inline] > __se_sys_epoll_wait fs/eventpoll.c:2465 [inline] > __x64_sys_epoll_wait+0xcf/0x3a0 fs/eventpoll.c:2465 > x64_sys_call+0x2ece/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:233 This lacks: Local variable now.i.i.i initialized at: ktime_get_ts64(&now); <---- HERE Right before the timespec64_add_safe() invocation *to = timespec64_add_safe(now, *to); KMSAN confused itself.... Thanks, tglx