On 2019-07-25 7:18 a.m., Nicholas Johnson wrote: > On Wed, Jul 24, 2019 at 08:38:14AM -0500, Bjorn Helgaas wrote: >> On Wed, Jul 24, 2019 at 12:54:00PM +0000, Nicholas Johnson wrote: >>> Hi all, >>> >>> I was just rebasing my patches for linux 5.3-rc1 and noticed a possible >>> regression that shows on both of my machines. It is also reproducible >>> with the unmodified Ubuntu mainline kernel, downloadable at [1]. >>> >>> Running the lspci command takes 1-3 seconds with 5.3-rc1 (rather than an >>> imperceivable amount of time). Booting with pci.dyndbg does not reveal >>> why. >>> >>> $ uname -r >>> 5.3.0-050300rc1-generic >>> $ time lspci -vt 1>/dev/null >>> >>> real 0m2.321s >>> user 0m0.026s >>> sys 0m0.000s >>> >>> If none of you are aware of this or what is causing it, I will submit a >>> bug report to Bugzilla. >> >> I wasn't aware of this; thanks for reporting it! I wasn't able to >> reproduce this in qemu. Can you play with "strace -r lspci -vt" and >> the like? Maybe try "lspci -n" to see if it's related to looking up >> the names? > > For a second you had me doubting myself - it could have been a Ubuntu > thing. But no, I just reproduced it on Arch Linux, and double checked > that it was not doing it on 5.2. Also, the problem occurs even without > the PCI kernel parameters which I usually pass. Ok, can you bisect to find the commit that causes this issue? Thanks, Logan
