[ Adding in the LKFT folks ]
On Mon, Jan 27, 2025 at 08:38:50PM +0000, Mark Brown wrote:
On Mon, Jan 27, 2025 at 11:12:11AM -0800, Linus Torvalds wrote:
On Mon, 27 Jan 2025 at 09:19, Sasha Levin <sashal@xxxxxxxxxx> wrote:
> With this pulled on top of Linus's tree, LKFT is managing to trigger
> kfence warnings:
> <3>[ 62.180289] BUG: KFENCE: out-of-bounds read in d_same_name+0x4c/0xd0
> <3>[ 62.180289]
> <3>[ 62.182647] Out-of-bounds read at 0x00000000eedd4b55 (64B right of kfence-#174):
> <4>[ 62.184178] d_same_name+0x4c/0xd0
Bah. I've said this before, but I really wish LKFT would use debug
builds and run the warnings through scripts/decode_stacktrace.sh.
Getting filenames and line numbers (and inlining information!) for
stack traces can be really really useful.
I think you are using KernelCI builds (at least that was the case last
time), and apparently they are non-debug builds. And that's possibly
due to just resource issues (the debug info does take a lot more disk
space and makes link times much longer too). So it might not be easily
fixable.
They're not, they're using their own builds done with their tuxsuite
service which is a cloud front end for their tuxmake tool, that does
have the ability to save the vmlinux. Poking around the LKFT output it
does look like they're doing that for the LKFT builds:
https://qa-reports.linaro.org/lkft/sashal-linus-next/build/v6.13-rc7-8584-gd4639f3659ae/testrun/27027254/suite/build/test/gcc-13-tinyconfig/details/
https://storage.tuxsuite.com/public/linaro/lkft/builds/2sDW1jDhjHPNl1XNezFhsjSlvpI/
so hopefully the information is all there and it's just a question of
people doing the decode when reporting issues from LKFT.
My understanding was that becuase CONFIG_DEBUG_INFO_NONE=y is set, we
actually don't have enough info to resolve line numbers.
I've tried running decode_stacktrace.sh on the vmlinux image linked
above, and indeed we can't get line numbers.
--
Thanks,
Sasha
