Hello! > I have been using lspci (v3.2.1) on Centos 7.2 to find out why a LSI 9420-4i > raid controller did not work with the linux driver but when I used lspci > with the -vv option as root the machine locked up completely and even the > reset button did not work. lspci v3.4.1 does the same. > As I was curious as to the reason why this could happen I compiled and ran > it under gdb and found that the cap_vpd() function caused the problem. The > raid card said that it supported vpd but the first call of read_vpd() > returned a value of FFh for the variable "tag" and the next call of > read_vpd() would hang the pc. > I added code to return from the function after the first read_vpd but when > the subsequent capability structures were read the values were different > from those previously dumped using the -xxx option and lspci would crash as > it followed the modified linked list off into oblivion. > I commented out the call to cap_vpd() and it worked correctly and I could > then see all the capability details. > > I would like to make a request that the call to cap_vpd be disabled by > default and enabled by a command line parameter if necessary as it is very > likely that it is the cause of problems with the -vv and -vvv options. As > this incident has shown, the consequences of reading the vpd can be very > dangerous. It smells of faulty hardware. Reading the VPD should not have any side effects. It seems to be a rather singular problem (your report was the first one I received since we added dumping of VPD in 2009) and it is not limited to lspci anyway -- other programs could crash your system by accessing the particular file in sysfs. I would recommend blacklisting your device in the kernel, so that VPD will not be provided by sysfs at all. Cc-ing linux-pci and asking for other opinions. Have a nice fortnight -- Martin `MJ' Mares <mj@xxxxxx> http://mj.ucw.cz/ Faculty of Math and Physics, Charles University, Prague, Czech Rep., Earth Anything is good and useful if it's made of chocolate. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
