Re: [LTP] [PATCH 2/2] device-drivers/rdma: Add ucma_uaf01 test

[Petr Vorel <pvorel@suse.cz>]

Hi Leon, all,

> On Tue, Apr 07, 2026 at 03:24:26PM +0200, Petr Vorel wrote:
> > Hi Andrea,

> > it's been long time since this use-after-free was fixed, but IMHO still useful
> > to have a test (it's also kind of smoke test for rdma_cm).
> > Anyway, LGTM, but it'd be nice to reproduce the bug.

> > Reviewed-by: Petr Vorel <pvorel@suse.cz>

> > > Test for use-after-free in RDMA UCMA triggered by racing CREATE_ID,
> > > BIND_IP, and LISTEN operations. Three threads concurrently issue
> > > these commands to /dev/infiniband/rdma_cm and the test checks for
> > > kernel taint (KASAN use-after-free detection).

> > > The bug was fixed by kernel commit 5fe23f262e05
> > > ("ucma: fix a use-after-free in ucma_resolve_ip()").

> > > Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
> > > ---
> > >  runtest/kernel_misc                               |   1 +
> > >  testcases/kernel/device-drivers/Makefile          |   1 +
> > >  testcases/kernel/device-drivers/rdma/.gitignore   |   1 +
> > >  testcases/kernel/device-drivers/rdma/Makefile     |   7 +
> > >  testcases/kernel/device-drivers/rdma/ucma_uaf01.c | 208 ++++++++++++++++++++++
> > >  5 files changed, 218 insertions(+)

> <...>

> > > +static struct tst_test test = {
> > > +	.test_all = run,
> > > +	.setup = setup,
> > > +	.cleanup = cleanup,
> > > +	.runtime = 300,
> > > +	.needs_root = 1,
> > > +	.taint_check = TST_TAINT_W | TST_TAINT_D,
> > > +	.needs_kconfigs = (const char *[]) {
> > > +		"CONFIG_INFINIBAND",
> > > +		"CONFIG_INFINIBAND_USER_ACCESS",

> I’m not familiar with the LTP tests, but I wanted to point out that these
> config options are insufficient. You need an actual or virtual RDMA device
> connected to rdma-cm for the tests to work correctly.

Leon, thanks for looking into it. FYI these are just config options to skip
kernels without required kernel modules. 

So using /dev/infiniband/rdma_cm (via RDMA_CM_DEV) is not enough, we need
another device?

Kind regards,
Petr