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 E60B62770A for ; Tue, 10 Feb 2026 19:00:33 +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=1770750034; cv=none; b=ZJYYL5FUOeI81jvdzXEmJO64XwuNTkBL+L00jnBomle4Zwry0BYK88QFSMgR1ulV/UcjU8ND1dKNbKYZxgGCE9qLcDYMhNJVNMSi0OAnG27m/tFJ+Rtep8HRLuHqvrJCw7TG7bNF8BLtKNC1Sarezslj9nBbXKx3xB7OncpP6tg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770750034; c=relaxed/simple; bh=OZbcFhHsgJxGMesDUeKXqtUB/vkSxytfoZTJsNnZ/v4=; h=From:To:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=uhcUWbzz4UTuFpiMAP2DVNGiPinRIrMpJS8SWpUTionVexpgrc2CJLXcmca1rpJc9YkBTZuzcJ1drf4oHEuyZ6OW4cPrLM2ogLfMwVQ5RDaqrvrZ2kt4B43//S7X0LmOMt4RCFhrSqt1cNETiqAEh+Dq/laMyPU8GBmmAUcvWG4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TNjHOmPS; 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="TNjHOmPS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1A3DFC19424; Tue, 10 Feb 2026 19:00:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770750033; bh=OZbcFhHsgJxGMesDUeKXqtUB/vkSxytfoZTJsNnZ/v4=; h=From:To:Subject:In-Reply-To:References:Date:From; b=TNjHOmPSaS+EUE9Ci6W/XEgxsM7+QbLNL84m1+eaDUyqYuuW8+ZKVM2hBg/b7K/vZ CD6UxXm6/wQfr4eCegldXHoZjAuxW7LJGR/T+eCgShqGgA2zSsOVd/ZhAAkg2SIhvi BEZVFTWuJGcY6z4Q3njDo4hzL1YD0+lkWe0nq3OW22vBuSeHG2u/FQ2E48+jKELGra CwijrZ8kk6fcwIGwKYdxAfCzKgte/t+NwvNjaIKzugtDdK5xUa1j7bepRrB+oYG3uL x15ns4MPRhDlEWjey4CO9q9azdj+ACK6uErSGY+qfhEsSjbN8DVkmmFxD38hofFBaj SWQSzbpm/4aWw== From: Thomas Gleixner To: syzbot , andrealmeid@igalia.com, dave@stgolabs.net, dvhart@infradead.org, linux-kernel@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [kernel?] WARNING in __mmdrop (2) In-Reply-To: <698aaf3c.050a0220.3b3015.0088.GAE@google.com> References: <698aaf3c.050a0220.3b3015.0088.GAE@google.com> Date: Tue, 10 Feb 2026 20:00:30 +0100 Message-ID: <87o6lwa0fl.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 Mon, Feb 09 2026 at 20:08, syzbot wrote: > HEAD commit: 05f7e89ab973 Linux 6.19 > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=1153465a580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=df890e720d1bb80 > dashboard link: https://syzkaller.appspot.com/bug?extid=237b5b985b78c1da9600 > compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=105297fa580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=120c12e6580000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/ea9f39c5175d/disk-05f7e89a.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/734edeebfa32/vmlinux-05f7e89a.xz > kernel image: https://storage.googleapis.com/syzbot-assets/a2cb36d849f0/bzImage-05f7e89a.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+237b5b985b78c1da9600@syzkaller.appspotmail.com Futexes are just a red herring here. The bug is a double mmput() introduced by: b5cbacd7f86f ("procfs: avoid fetching build ID while holding VMA lock") See https://lore.kernel.org/all/87qzqsa1br.ffs@tglx/ Thanks, tglx