From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 E8F8B415F29; Fri, 4 Sep 2026 05:54:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788501267; cv=none; b=jMHTVx/Y0eTb2qubucIzMfQpH7roc/yVUk/qZx/efXfmtxEQVIBLyL9XOkJGjHBtnI1XP8ePN1bRrqCVwqmVU7wHH1DMgS4O7u0WZBFKav3/Cs2XVVWNFaVAwRgdJkRKJcyaybDc47Fm2LidrBVJd/CUKK6nGozKchC1K/iJd0E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788501267; c=relaxed/simple; bh=lbG9lSjvNTiGOxa2Ma2z7XHg0J8s/e0y85QeYUe9g7o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MMM1sAyiXc2IoV3an17HwkavOK6k0YSOGx+FtcAy2IOeq61vbosEoP4i4bDMRLuQbbUC2Swur5EkG5kYCRxjpmq2/KVYoBVfICOZ3CsBySKwfEv6+cN+/53arzrZj/eshqAfLzkpsQdpTkmYNlJef+KT66jiQmX319SOAVdKaMg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Zkk3DlLr; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Zkk3DlLr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4EF2A1F00A3D; Fri, 4 Sep 2026 05:54:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788501265; bh=fJEMlai+40A36/CRsuluj8RMU0DnViYS3e89XmOPdUg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Zkk3DlLr6Zf/cCeF9bYntaq0JjEI4l5Gc3f67DVxc5YVovs19fCMEmeoro4Nc+owJ VFixoYXfEwYjK4SdghxLYLMBbXcZX/73Yykqvyu4ibc6R8qk+6mQkUEPCNxzRAiVui AhsBQWFPqHwIBKiYw67XHCI3VateL7o5HrIKgfvU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Petr Vaganov , Bart Van Assche , "Martin K. Petersen (Oracle)" Subject: [PATCH 6.18 306/552] scsi: core: Fill in DMA padding bytes in scsi_alloc_sgtables() Date: Fri, 4 Sep 2026 06:57:43 +0200 Message-ID: <20260904045757.210420212@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045747.813364717@linuxfoundation.org> References: <20260904045747.813364717@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Petr Vaganov commit 626147717bea776b61ed3631d2c26283760c4cc4 upstream. During fuzz testing, the following issue was discovered: BUG: KMSAN: uninit-value in __dma_map_sg_attrs+0x217/0x310 __dma_map_sg_attrs+0x217/0x310 dma_map_sg_attrs+0x4a/0x70 ata_qc_issue+0x9f8/0x1420 __ata_scsi_queuecmd+0x1657/0x1740 ata_scsi_queuecmd+0x79a/0x920 scsi_queue_rq+0x4472/0x4f40 blk_mq_dispatch_rq_list+0x1cca/0x3ee0 __blk_mq_sched_dispatch_requests+0x458/0x630 blk_mq_sched_dispatch_requests+0x15b/0x340 __blk_mq_run_hw_queue+0xe5/0x250 __blk_mq_delay_run_hw_queue+0x138/0x780 blk_mq_run_hw_queue+0x4bb/0x7e0 blk_mq_sched_insert_request+0x2a7/0x4c0 blk_execute_rq+0x497/0x8a0 sg_io+0xbe0/0xe20 scsi_ioctl+0x2b36/0x3c60 sr_block_ioctl+0x319/0x440 blkdev_ioctl+0x80f/0xd70 __se_sys_ioctl+0x219/0x420 __x64_sys_ioctl+0x93/0xe0 x64_sys_call+0x1d6c/0x3ad0 do_syscall_64+0x4c/0xa0 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 Uninit was created at: __alloc_pages+0x5c0/0xc80 alloc_pages+0xe0e/0x1050 blk_rq_map_user_iov+0x2b77/0x6100 blk_rq_map_user_io+0x2fa/0x4d0 sg_io+0xad6/0xe20 scsi_ioctl+0x2b36/0x3c60 sr_block_ioctl+0x319/0x440 blkdev_ioctl+0x80f/0xd70 __se_sys_ioctl+0x219/0x420 __x64_sys_ioctl+0x93/0xe0 x64_sys_call+0x1d6c/0x3ad0 do_syscall_64+0x4c/0xa0 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 Bytes 14-15 of 16 are uninitialized Memory access of size 16 starts at ffff88800cbdb000 When processing the last unaligned element of the scatterlist, it is supplemented with missing bytes in the amount of pad_len. These bytes remain uninitialized, which leads to a problem. Extend last_sg->length by pad_len first, then use sg_zero_buffer() to zero those pad_len bytes. sg_zero_buffer() uses sg_miter internally, which correctly handles sg entries spanning multiple pages and padding that crosses a page boundary. Found by Linux Verification Center (linuxtesting.org) with Syzkaller. Fixes: 40b01b9bbdf5 ("block: update bio according to DMA alignment padding") Cc: stable@vger.kernel.org Signed-off-by: Petr Vaganov Reviewed-by: Bart Van Assche Link: https://patch.msgid.link/20260628185229.37957-1-p.vaganov@ideco.ru Signed-off-by: Martin K. Petersen (Oracle) Signed-off-by: Greg Kroah-Hartman --- drivers/scsi/scsi_lib.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1184,8 +1184,10 @@ blk_status_t scsi_alloc_sgtables(struct if (blk_rq_bytes(rq) & rq->q->limits.dma_pad_mask) { unsigned int pad_len = (rq->q->limits.dma_pad_mask & ~blk_rq_bytes(rq)) + 1; + unsigned int data_len = last_sg->length; last_sg->length += pad_len; + sg_zero_buffer(last_sg, 1, pad_len, data_len); cmd->extra_len += pad_len; }