Great, that works. Thank you a lot! ./smartctl /dev/sda -dmegaraid,24 -t long smartctl 5.41 2010-11-05 r3203 [x86_64-unknown-linux-gnu] (local build) Copyright (C) 2002-10 by Bruce Allen, http://smartmontools.sourceforge.net Extended Background Self Test has begun Please wait 22 minutes for test to complete. Estimated completion time: Thu Nov 11 17:44:50 2010 11.11.2010 20:06, BjÃrn Mork ÐÐÑÐÑ:
Bokhan Artem<aptem@xxxxxx> writes:Hello. I have kernel problems when trying to run smart commands on LSI-92xx controller. Running self-test on SAS disk (smartctl /dev/sda -dmegaraid,24 -t long) with smartmontools causes kernel oops (?) (and segfault). Look in attachment for dmesg. strace of smartctl: mknod("/dev/megaraid_sas_ioctl_node", S_IFCHR, makedev(251, 0)) = -1 EEXIST (File exists) close(4) = 0 munmap(0x7f4be3a9f000, 4096) = 0 open("/dev/megaraid_sas_ioctl_node", O_RDWR) = 4 ioctl(4, MTRRIOC_SET_ENTRY, 0x7fffa574ed30) = 0 ioctl(4, MTRRIOC_SET_ENTRY, 0x7fffa574eb30) = 0 ioctl(4, MTRRIOC_SET_ENTRY<unfinished ...> +++ killed by SIGSEGV +++ Viewing smart info is OK (smartctl /dev/sda -dmegaraid,24 -a). Running self-test on SATA disk on the same system is OK. The problem is reproducible with 2.6.32 and 2.6.36 kernels.A quick look at this reveals that smartctl will happily do a MEGASAS_IOC_FIRMWARE ioctl with sge_count = 1 and sgl[0].iov_len = 0 if it is sending a command with dataLen == 0 : /* Issue passthrough scsi command to PERC5/6 controllers */ bool linux_megaraid_device::megasas_cmd(int cdbLen, void *cdb, int dataLen, void *data, int /*senseLen*/, void * /*sense*/, int /*report*/) { struct megasas_pthru_frame *pthru; struct megasas_iocpacket uio; struct megasas_iocpacket uio; int rc; memset(&uio, 0, sizeof(uio)); pthru = (struct megasas_pthru_frame *)uio.frame.raw; pthru->cmd = MFI_CMD_PD_SCSI_IO; int rc; memset(&uio, 0, sizeof(uio)); pthru = (struct megasas_pthru_frame *)uio.frame.raw; pthru->cmd = MFI_CMD_PD_SCSI_IO; pthru->cmd_status = 0xFF; pthru->scsi_status = 0x0; pthru->target_id = m_disknum; pthru->lun = 0; pthru->cdb_len = cdbLen; pthru->timeout = 0; pthru->flags = MFI_FRAME_DIR_READ; pthru->sge_count = 1; pthru->data_xfer_len = dataLen; pthru->sgl.sge32[0].phys_addr = (intptr_t)data; pthru->sgl.sge32[0].length = (uint32_t)dataLen; memcpy(pthru->cdb, cdb, cdbLen); uio.host_no = m_hba; uio.sge_count = 1; uio.sgl_off = offsetof(struct megasas_pthru_frame, sgl); uio.sgl[0].iov_base = data; uio.sgl[0].iov_len = dataLen; rc = 0; errno = 0; rc = ioctl(m_fd, MEGASAS_IOC_FIRMWARE,&uio); if (pthru->cmd_status || rc != 0) { if (pthru->cmd_status == 12) { return set_err(EIO, "megasas_cmd: Device %d does not exist\n", m_disknum); } return set_err((errno ? errno : EIO), "megasas_cmd result: %d.%d = %d/%d", m_hba, m_disknum, errno, pthru->cmd_status); } return true; } The kernel bug is that the zero valued sgl[0].iov_len is passed unmodified to megasas_mgmt_fw_ioctl() which again passes it on as size to dma_alloc_coherent(): /* * For each user buffer, create a mirror buffer and copy in */ for (i = 0; i< ioc->sge_count; i++) { kbuff_arr[i] = dma_alloc_coherent(&instance->pdev->dev, ioc->sgl[i].iov_len, &buf_handle, GFP_KERNEL); And it looks like most (all?) of the dma_alloc_coherent() implementations will use get_order(size) to compute the necessary allocation. This will fail if size == 0. On the other hand, I may have misunderstood this entirely.... But if you dare, you could try the attached patch (compile tested only as I don't have the hardware) and see if it helps. Let me know how it goes, and I'll forward it to the megaraid manitainers if it really fixes your problem. BjÃrn
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