From: Arnd Bergmann arnd@arndb.de
[ Upstream commit b112036535eda34460677ea883eaecc3a45a435d ]
Phil Oester reported that a fix for a possible buffer overrun that I sent caused a regression that manifests in this output:
Event Message: A PCI parity error was detected on a component at bus 0 device 5 function 0. Severity: Critical Message ID: PCI1308
The original code tried to handle the sense data pointer differently when using 32-bit 64-bit DMA addressing, which would lead to a 32-bit dma_addr_t value of 0x11223344 to get stored
32-bit kernel: 44 33 22 11 ?? ?? ?? ?? 64-bit LE kernel: 44 33 22 11 00 00 00 00 64-bit BE kernel: 00 00 00 00 44 33 22 11
or a 64-bit dma_addr_t value of 0x1122334455667788 to get stored as
32-bit kernel: 88 77 66 55 ?? ?? ?? ?? 64-bit kernel: 88 77 66 55 44 33 22 11
In my patch, I tried to ensure that the same value is used on both 32-bit and 64-bit kernels, and picked what seemed to be the most sensible combination, storing 32-bit addresses in the first four bytes (as 32-bit kernels already did), and 64-bit addresses in eight consecutive bytes (as 64-bit kernels already did), but evidently this was incorrect.
Always storing the dma_addr_t pointer as 64-bit little-endian, i.e. initializing the second four bytes to zero in case of 32-bit addressing, apparently solved the problem for Phil, and is consistent with what all 64-bit little-endian machines did before.
I also checked in the history that in previous versions of the code, the pointer was always in the first four bytes without padding, and that previous attempts to fix 64-bit user space, big-endian architectures and 64-bit DMA were clearly flawed and seem to have introduced made this worse.
Link: https://lore.kernel.org/r/20210104234137.438275-1-arnd@kernel.org Fixes: 381d34e376e3 ("scsi: megaraid_sas: Check user-provided offsets") Fixes: 107a60dd71b5 ("scsi: megaraid_sas: Add support for 64bit consistent DMA") Fixes: 94cd65ddf4d7 ("[SCSI] megaraid_sas: addded support for big endian architecture") Fixes: 7b2519afa1ab ("[SCSI] megaraid_sas: fix 64 bit sense pointer truncation") Reported-by: Phil Oester kernel@linuxace.com Tested-by: Phil Oester kernel@linuxace.com Signed-off-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/megaraid/megaraid_sas_base.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c index 83d25ee88f028..8877a21102f1d 100644 --- a/drivers/scsi/megaraid/megaraid_sas_base.c +++ b/drivers/scsi/megaraid/megaraid_sas_base.c @@ -7323,11 +7323,9 @@ megasas_mgmt_fw_ioctl(struct megasas_instance *instance, goto out; }
+ /* always store 64 bits regardless of addressing */ sense_ptr = (void *)cmd->frame + ioc->sense_off; - if (instance->consistent_mask_64bit) - put_unaligned_le64(sense_handle, sense_ptr); - else - put_unaligned_le32(sense_handle, sense_ptr); + put_unaligned_le64(sense_handle, sense_ptr); }
/*