From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr2-f12.google.com (mail-wr2-f12.google.com [74.125.225.76]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 91FDF41A79C for ; Thu, 24 Sep 2026 09:49:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.225.76 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790243376; cv=none; b=t2dYZ35mwLdkhK8s/MI5fK8zOGbosbstQ3Mg2cgAAi33w0lep7r2q8dWw3VTaQglM2T68OGF8jBltWu6LmXwbzfSKOkxIPilfJZQrm8Gh6LpJVuoC1EdfoRUCRcjVCle59cRcsZIkOdVIdU1njgb6HmSFTwGGV2L5VKqYpsQfJg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790243376; c=relaxed/simple; bh=6AxHVVl+gZTn8j7aNuoJz+d9M/a0mR4Yz8N6BMkLiwM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=bVRa7oE3zARBOETwuDnZqvTRwSJdmwCuZqxO+UUv4rnsPmAu3QG+ll4hGidrQoPQsA8bHv6ngXL1qBOEP2gx2Tfjg2CnxUiIsrCJLklpEdcsZniB/VnNfxsQ/Np3R0vS31rDZ+0xoXlZkkCAGCcR+OYQNNBj4VfeyHGdpIF1cDQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.com; spf=pass smtp.mailfrom=gmail.com; arc=none smtp.client-ip=74.125.225.76 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-wr2-f12.google.com with SMTP id ffacd0b85a97d-482f6350faaso1194488f8f.0 for ; Thu, 24 Sep 2026 02:49:21 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790243358; x=1790848158; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=wBClDNoiMcfukXqTKxUO0O44/6vZOeXszispr41Gs0A=; b=tdPdSvb5CfVb18s74uaQ2NOANGxVixzgdF+Ins87clUMAP31qOBI5XO2uEyZbt1IFu mVEhOb8zOf5DzRHceTXFLHGMK+wb8UMilud2mHguNSn3nUz96+SS9s4ELaqTSrpchg9X NWkoRQbHjCrXAc3CXS6fiiL/I5l7xAV9BZXTkN+63Dlsarpx7CzIsxmvLCDpr6ndK+Qk FOXOuUp6xsNVaGcpWE+aUydHQ6ccuryCA60vPpzQL7lqIaq5Ui5eLnV38O7OCesiKvDx vjRTp7a7yDQriejgFlRGoC0iNtxL2BJzH2Bt3p/FjtbQPTnKw9v5wremOLJ1aWhUQFGe WA4Q== X-Gm-Message-State: AFuF++ls5LdDckf/Y2wWKu0K4vPP1ShxBMuiFw7RjduA3v+lHRwA4VCZ v5+nDD4clTyqK1ZSHApA5iMRe8+ww+cq4F9DHJWicYPQamoWiy/BbJChYl05aQ== X-Gm-Gg: AYBFou2nbsuoyFK6isPUrGSpqZs/BH0MCK6mlmiyEuhuqVNS096AKk2WOoZUhoaAOH/ 5pCxMImeR638HYUvElGHHUU1gQ6MhMm5bdzyx9CO55A+RBtXp9BydQ9c2N/J2RwKyBzwZqqWDwB ZpEpNmuxV1yUn/cmpCjJzuPe5/SHt+PKXcS7VQLhGkRdzcZmdsg/QalVLjtT753/JVjSN6WYpN2 p2lPphvQO4fQvGqaKFgrJrWgmn3nMbpO4yNjhUCwd7lOkINBDSnZDMHfQb237mCOxHVdNrwb9oc HQtZIqK9rJaIDCmrO8v7BIcVPtnYtxqFHtrblToVxayhRgZf6Xr58QG3HA2ydMuR4YTX9SKTnYY AS0zj+HTUamz88p7DTP45crAbF9gHgJMIE9+8rcohqlNtRI6v6CUhxy82wNV5rgliNfVJNusQ77 kEq8vrSHOgnCaHJ2LtgrmeLdm/BNcWyN2vplSKOJaEHeBM/j95hI8hYq3aTLU= X-Received: by 2002:a05:6000:2584:b0:487:8ec:1fc with SMTP id ffacd0b85a97d-4887170d3f8mr3448462f8f.12.1790243358351; Thu, 24 Sep 2026 02:49:18 -0700 (PDT) Received: from white ([5.194.185.161]) by smtp.googlemail.com with ESMTPSA id ffacd0b85a97d-4886876c027sm14791908f8f.17.2026.09.24.02.49.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 24 Sep 2026 02:49:17 -0700 (PDT) From: "Denis Efremov (Oracle)" To: linux-block@vger.kernel.org Cc: linux-kernel@vger.kernel.org, "Denis Efremov (Oracle)" , stable@vger.kernel.org, syzbot+874c2707f97fac24b090@syzkaller.appspotmail.com Subject: [PATCH] floppy: don't store a stack buffer in timeout_message Date: Thu, 24 Sep 2026 13:48:39 +0400 Message-ID: <20260924094839.3239569-1-efremov@linux.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit request_done() formats "request done %d" into a buffer on its stack and passes it to reschedule_timeout(), which keeps the pointer in timeout_message. show_floppy() prints timeout_message long after request_done() has returned, e.g. from result() in the interrupt handler, and reads a dead stack frame: BUG: KASAN: stack-out-of-bounds in string+0x39c/0x3d0 lib/vsprintf.c:720 Read of size 1 at addr ffffc900003cfc70 by task swapper/3/0 Call Trace: ... show_floppy+0xb1/0x45f drivers/block/floppy.c:1838 result.cold+0x2b/0x30 drivers/block/floppy.c:1183 floppy_interrupt+0x191/0x340 drivers/block/floppy.c:1755 floppy_hardint+0x1a7/0x200 arch/x86/include/asm/floppy.h:66 uptodate is either 0 or 1, so pass one of two string literals instead. Cc: stable@vger.kernel.org Fixes: 73507e6cd8dc ("drivers/block/floppy.c: remove unnecessary argument from [__]reschedule_timeout") Reported-by: syzbot+874c2707f97fac24b090@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=874c2707f97fac24b090 Signed-off-by: Denis Efremov (Oracle) --- drivers/block/floppy.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index f04397b8e381..02a34de69102 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -2276,11 +2276,10 @@ static void request_done(int uptodate) { struct request *req = current_req; int block; - char msg[sizeof("request done ") + sizeof(int) * 3]; probing = 0; - snprintf(msg, sizeof(msg), "request done %d", uptodate); - reschedule_timeout(MAXTIMEOUT, msg); + reschedule_timeout(MAXTIMEOUT, + uptodate ? "request done 1" : "request done 0"); if (!req) { pr_info("floppy.c: no request in request_done\n"); base-commit: 62f4c998b297cf233997a2b4cd6fc2d2df0319c9 -- 2.55.0