Sorry it seems mutt ate my To:, so adding the folks I intended to address on the To: field now :) Luis On Fri, Jun 19, 2020 at 08:46:26PM +0000, Luis Chamberlain wrote: > On Wed, Jun 17, 2020 at 05:43:48PM -0700, Andrew Morton wrote: > > On Wed, 10 Jun 2020 15:49:18 +0000 "Luis R. Rodriguez" <mcgrof@xxxxxxxxxx> wrote: > > > > > Tiezhu Yang had sent out a patch set with a slew of kmod selftest > > > fixes, and one patch which modified kmod to return 254 when a module > > > was not found. This opened up pandora's box about why that was being > > > used for and low and behold its because when UMH_WAIT_PROC is used > > > we call a kernel_wait4() call but have never unwrapped the error code. > > > The commit log for that fix details the rationale for the approach > > > taken. I'd appreciate some review on that, in particular nfs folks > > > as it seems a case was never really hit before. > > > > > > This goes boot tested, selftested with kmod, and 0-day gives its > > > build blessings. > > > > Any thoughts on which kernel version(s) need some/all of these fixes? > > Well, in so far as fixes, this is the real important part: > > * request_module() used to fail with an error code of > 256 when a module was not found. Now it properly > returns 1. > > * fs/nfsd/nfs4recover.c: we never were disabling the > upcall as the error code of -ENOENT or -EACCES was > *never* properly checked for error code > > Since the request_module() fix is only affecting userspace > for the kmod tests, through the kmod test driver, ie, we don't expose > this to userspace in any other place, I don't see that as critical. > Let me be clear, we have a test_kmod driver which exposes knobs > and one of the knobs lets userspace query the return value of a > request_module() call, and we use this test_kmod driver to stress > test kmod loader. Let us also recall that the fix is *iff* an error > *did* occur. I *cannot* think of a reason why this would be critical > to merge to older stable kernels for this reason for request_module()'s > sake. > > Bruce, Chuck: > > But... for NFS... I'd like the NFS folks to really look at that > and tell us is some folks really should care about that. I also > find it perplexing there was a comment in place there to *ensure* > the error was checked for, and so it seemed someone cared for that > condition. > > > > drivers/block/drbd/drbd_nl.c | 20 +++++------ > > > fs/nfsd/nfs4recover.c | 2 +- > > > include/linux/sched/task.h | 13 ++++++++ > > > kernel/kmod.c | 5 ++- > > > kernel/umh.c | 4 +-- > > > lib/test_kmod.c | 2 +- > > > net/bridge/br_stp_if.c | 10 ++---- > > > security/keys/request_key.c | 2 +- > > > tools/testing/selftests/kmod/kmod.sh | 50 +++++++++++++++++++++++----- > > > > I'm not really sure who takes kmod changes - I'll grab these unless > > someone shouts at me. > > Greg usually takes it, but as usual, thanks for picking up the slack ;) > > Luis
