Hi Badari, On Mon, 15 Aug 2022 21:51:04 +0000 "Pulavarty, Badari" <badari.pulavarty@xxxxxxxxx> wrote: > [-- Attachment #1: Type: text/plain, Size: 350 bytes --] > > Hi SI, > > > Nice finding, thank you! But, the return value of the debugfs call is intentionally ignored[2]. How about doing the duplicated name check in > > dbgfs_mk_context() itself before the debugfs_create_dir() call? Please don't unwrap wrapped message. My monitor is not so wide :'( > > > > [2] https://lore.kernel.org/linux-mm/20210205155902.31102-1-sjpark@xxxxxxxxxx/ > > How about this? > > Thanks, > Badari > > > > [-- Attachment #2: damon-mkcontext-fix.patch --] > [-- Type: application/octet-stream, Size: 858 bytes --] Could you please don't send a patch as an attached file of the mail but put it in the mail body so that we can easily read the patch and comment in line? > > damon dbgfs_mk_context() should check to make sure there is no existing > context with the same name. Otherwise, it will cause failure when we > enabling the monitor. > > Test case: > > echo "off" > /sys/kernel/debug/damon/monitor_on > echo "abc" > /sys/kernel/debug/damon/mk_context > echo "abc" > /sys/kernel/debug/damon/mk_context > echo <pid> > /sys/kernel/debug/damon/abc/target_ids > echo "on" > /sys/kernel/debug/damon/monitor_on <<< fails > > Signed-off-by: Badari Pulavarty <badari.pulavarty@xxxxxxxxx> > --- It would be good to put the changelog of this patch here: https://docs.kernel.org/process/submitting-patches.html#the-canonical-patch-format > --- a/mm/damon/dbgfs.c 2022-08-15 14:27:38.308806431 -0700 > +++ b/mm/damon/dbgfs.c 2022-08-15 14:33:31.661163048 -0700 > @@ -817,6 +817,12 @@ > if (!root) > return -ENOENT; > > + new_dir = debugfs_lookup(name, root); > + if (new_dir) { > + dput(new_dir); > + return -EEXIST; > + } > + The change looks ok to me at a glance, but the attached file seems not an appropriate patch. Could you please repost this as a formal patch as suggested for a better review? Thanks, SJ > new_dir = debugfs_create_dir(name, root); > dbgfs_dirs[dbgfs_nr_ctxs] = new_dir;
