On Thu, Oct 26, 2023 at 02:35:11PM -0700, Alexei Starovoitov wrote: > On Tue, Oct 24, 2023 at 10:42 PM Manu Bretelle <chantr4@xxxxxxxxx> wrote: > > > > On Tue, Oct 24, 2023 at 02:29:19PM -0700, Kui-Feng Lee wrote: > > > > > > > > > On 10/24/23 13:18, Manu Bretelle wrote: > > > > Currently this tests tries to umount /sys/kernel/debug (TDIR) but the > > > > system it is running on may have mounts below. > > > > > > > > For example, danobi/vmtest [0] VMs have > > > > mount -t tracefs tracefs /sys/kernel/debug/tracing > > > > as part of their init. > > > > > > > > This change list mounts and will umount any mounts below TDIR before > > > > umounting TDIR itself. > > > > > > > > Note that it is not umounting recursively, so in the case of a sub-mount > > > > of TDIR having another sub-mount, this will fail as mtab is ordered. > > > > > > Should we move TID to a random path likes "/sys/kernel/debug-<pid>/"? > > > > > > > Fair point, I suppose we would want to keep TDIR a defined string as it does > > simplify the gymnastic involved through the rest of the script, but yeah > > looking at the original commit: > > edb65ee5aa25 (selftests/bpf: Add bpffs preload test) > > > > I don't see any reason to use an alternate directory and rather mkdir it vs > > umounting the original one. > > so something like > > > > #define TDIR "/sys/kernel/test_bpffs" > > > > Would probably do. > > > > Alexei could confirm his original intent probably. > > I don't remember why I picked /sys/kernel/debug back then. > I suspect TDIR /tmp/foo and mkdir would work the same way. Yeah. I suspect the reason you used an existing directory is that /sys/kernel is not mutable from userspace. I ended up picking a random name under /tmp and mkdir.
