Messages in this thread | | | Date | Thu, 22 Sep 2022 13:18:12 -0400 | From | Phil Auld <> | Subject | Re: aarch64 5.15.68 regression in topology/thread_siblings (huge file size and no content) |
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On Thu, Sep 22, 2022 at 04:05:04PM +0200 Petr Štetiar wrote: > Phil Auld <pauld@redhat.com> [2022-09-22 09:18:47]: > > Hi, > > > I've seen the size cause problems for tools. Are we sure that it's the empty file and not > > the size causing issues? Maybe something is treating that as signed again for a count of > > -1 bytes (which seems like it would be a bug anyway)? > > root@OpenWrt:/# strace cat /sys/devices/system/cpu/cpu1/topology/thread_siblings > ...snip... > openat(AT_FDCWD, "/sys/devices/system/cpu/cpu1/topology/thread_siblings", O_RDONLY|O_LARGEFILE) = 3 > sendfile(1, 3, NULL, 16777216) = 0 > > root@OpenWrt:/# strace md5sum /sys/devices/system/cpu/cpu1/topology/thread_sibli > ...snip... > openat(AT_FDCWD, "/sys/devices/system/cpu/cpu1/topology/thread_siblings", O_RDONLY|O_LARGEFILE) = 3 > read(3, "", 4096) = 0 > > root@OpenWrt:/# strace head /sys/devices/system/cpu/cpu1/topology/thread_siblings > ...snip... > openat(AT_FDCWD, "/sys/devices/system/cpu/cpu1/topology/thread_siblings", O_RDONLY|O_LARGEFILE) = 3 > read(3, "", 1024) = 0 >
I tried this with the latest upstream (which doesn't yet have the fix for the size issue) and got the same results.
Then I applied the fix and the problem went away:
6.0.0-rc6.nr_cpus2+ # find /sys -name thread_siblings -exec cat \{\} \; 2 1
Cheers, Phil
> Cheers, > > Petr >
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