This patchset ensures that the number of hugepages is correctly set in the
system so that the uffd-stress test does not fail due to the racy nature of
the test. Patch 1 corrects the hugepage constraint in the run_vmtests.sh
script, whereas patch 2 corrects the constraint in the test itself.
Dev Jain (2):
selftests/mm/uffd-stress: Make test operate on less hugetlb memory
selftests/mm/uffd-stress: Stricten constraint on free hugepages before
the test
tools/testing/selftests/mm/run_vmtests.sh | 2 +-
tools/testing/selftests/mm/uffd-stress.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
--
2.30.2
Some high-level virtual drivers need to compute features from their
lower devices, but each currently has its own implementation and may
miss some feature computations. This patch set introduces a common function
to compute features for such devices.
Currently, bonding, team, and bridge have been updated to use the new
helper.
v2:
a) remove hard_header_len setting. I will set needed_headroom for bond/team
in a separate patch as bridge has it's own ways. (Ido Schimmel)
b) Add test file to Makefile, set RET=0 to a proper location. (Ido Schimmel)
Hangbin Liu (5):
net: add a common function to compute features from lowers devices
bonding: use common function to compute the features
team: use common function to compute the features
net: bridge: use common function to compute the features
selftests/net: add offload checking test for virtual interface
drivers/net/bonding/bond_main.c | 99 +----------
drivers/net/team/team_core.c | 73 +-------
include/linux/netdevice.h | 19 +++
net/bridge/br_if.c | 22 +--
net/core/dev.c | 76 +++++++++
tools/testing/selftests/net/Makefile | 1 +
tools/testing/selftests/net/config | 2 +
tools/testing/selftests/net/vdev_offload.sh | 176 ++++++++++++++++++++
8 files changed, 285 insertions(+), 183 deletions(-)
create mode 100755 tools/testing/selftests/net/vdev_offload.sh
--
2.50.1
From: Fred Griffoul <griffoul(a)casper.infradead.org>
This patch series addresses performance issues in nested VMX when
handling unmanaged guest memory. Unmanaged guest memory refers to memory
not directly mapped by the kernel (no struct page), such as memory
passed with the mem= parameter or guest_memfd for non-Confidential
Computing (CoCo) VMs.
Current Problem:
During nested VMX operations, the system frequently accesses specific
guest pages during L2 VM entry/exit cycles. The current workflow:
1. kvm_vcpu_map() invokes memremap() for unmanaged memory.
2. The system either directly accesses mapped memory via nested VMX or
passes it to the L2 guest through vmcs02.
3. kvm_vcpu_unmap() invokes memunmap()
This repeated map/unmap cycle creates significant performance overhead
due to expensive remapping operations.
Solution approach:
Our solution replaces kvm_host_map with gfn_to_pfn_cache in nested VMX.
It addresses two distinct types of guest pages.
First, we handle the L1 MSR bitmap page, which requires read-only access
for folding L1 and L0 MSR bitmap. We implement this conversion to
gfn_to_pfn_cache in patch 1.
Second, we tackle system pages, including APIC access, virtual APIC, and
posted interrupt descriptor pages. These pages are more complex as
they're accessed by both nested VMX code _and_ passed to the L2 guest in
vmcs02 fields. This requires to restore and complete the
"guest-uses-pfn" support in pfncache through patches 2 and 3, followed
by implementing kvm_host_map replacement with caches in patch 4.
Testing:
Patch 5 introduces a new selftest to verify cache invalidation and
memslot update functionality.
The changes are available in a git repository at:
git://git.infradead.org/users/griffoul/linux.git tags/nvmx-gpc-v1
Suggested-by: dwmw(a)amazon.co.uk
Fred Griffoul (5):
KVM: nVMX: Implement cache for L1 MSR bitmap
KVM: pfncache: Restore guest-uses-pfn support
KVM: x86: Add nested state validation for pfncache support
KVM: nVMX: Implement cache for L1 APIC pages
KVM: selftests: Add nested VMX APIC cache invalidation test
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/vmx/nested.c | 213 +++++++++---
arch/x86/kvm/vmx/vmx.h | 10 +-
arch/x86/kvm/x86.c | 14 +-
include/linux/kvm_host.h | 34 +-
include/linux/kvm_types.h | 1 +
tools/testing/selftests/kvm/Makefile.kvm | 1 +
.../selftests/kvm/x86/vmx_apic_update_test.c | 302 ++++++++++++++++++
virt/kvm/kvm_main.c | 3 +-
virt/kvm/kvm_mm.h | 6 +-
virt/kvm/pfncache.c | 43 ++-
11 files changed, 575 insertions(+), 53 deletions(-)
create mode 100644 tools/testing/selftests/kvm/x86/vmx_apic_update_test.c
--
2.51.0
Replace the hardcoded 0xff in test_icr() with the actual number of vcpus
created for the vm. This address the existing TODO and keeps the test
correct if it is ever run with multiple vcpus.
Signed-off-by: Sukrut Heroorkar <hsukrut3(a)gmail.com>
---
tools/testing/selftests/kvm/x86/xapic_state_test.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/kvm/x86/xapic_state_test.c b/tools/testing/selftests/kvm/x86/xapic_state_test.c
index fdebff1165c7..4af36682503e 100644
--- a/tools/testing/selftests/kvm/x86/xapic_state_test.c
+++ b/tools/testing/selftests/kvm/x86/xapic_state_test.c
@@ -56,6 +56,17 @@ static void x2apic_guest_code(void)
} while (1);
}
+static unsigned int vm_nr_vcpus(struct kvm_vm *vm)
+{
+ struct kvm_vcpu *vcpu;
+ unsigned int count = 0;
+
+ list_for_each_entry(vcpu, &vm->vcpus, list)
+ count++;
+
+ return count;
+}
+
static void ____test_icr(struct xapic_vcpu *x, uint64_t val)
{
struct kvm_vcpu *vcpu = x->vcpu;
@@ -124,7 +135,7 @@ static void test_icr(struct xapic_vcpu *x)
* vCPUs, not vcpu.id + 1. Arbitrarily use vector 0xff.
*/
icr = APIC_INT_ASSERT | 0xff;
- for (i = 0; i < 0xff; i++) {
+ for (i = 0; i < vm_nr_vcpus(vcpu->vm); i++) {
if (i == vcpu->id)
continue;
for (j = 0; j < 8; j++)
--
2.43.0
Recent changes to make netlink socket memory accounting must
have broken the implicit assumption of the netlink-dump test
that we can fit exactly 64 dumps into the socket. Handle the
failure mode properly, and increase the dump count to 80
to make sure we still run into the error condition if
the default buffer size increases in the future.
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
---
tools/testing/selftests/net/netlink-dumps.c | 43 ++++++++++++++++-----
1 file changed, 33 insertions(+), 10 deletions(-)
diff --git a/tools/testing/selftests/net/netlink-dumps.c b/tools/testing/selftests/net/netlink-dumps.c
index 07423f256f96..7618ebe528a4 100644
--- a/tools/testing/selftests/net/netlink-dumps.c
+++ b/tools/testing/selftests/net/netlink-dumps.c
@@ -31,9 +31,18 @@ struct ext_ack {
const char *str;
};
-/* 0: no done, 1: done found, 2: extack found, -1: error */
-static int nl_get_extack(char *buf, size_t n, struct ext_ack *ea)
+enum get_ea_ret {
+ ERROR = -1,
+ NO_CTRL = 0,
+ FOUND_DONE,
+ FOUND_ERR,
+ FOUND_EXTACK,
+};
+
+static enum get_ea_ret
+nl_get_extack(char *buf, size_t n, struct ext_ack *ea)
{
+ enum get_ea_ret ret = NO_CTRL;
const struct nlmsghdr *nlh;
const struct nlattr *attr;
ssize_t rem;
@@ -41,15 +50,19 @@ static int nl_get_extack(char *buf, size_t n, struct ext_ack *ea)
for (rem = n; rem > 0; NLMSG_NEXT(nlh, rem)) {
nlh = (struct nlmsghdr *)&buf[n - rem];
if (!NLMSG_OK(nlh, rem))
- return -1;
+ return ERROR;
- if (nlh->nlmsg_type != NLMSG_DONE)
+ if (nlh->nlmsg_type == NLMSG_ERROR)
+ ret = FOUND_ERR;
+ else if (nlh->nlmsg_type == NLMSG_DONE)
+ ret = FOUND_DONE;
+ else
continue;
ea->err = -*(int *)NLMSG_DATA(nlh);
if (!(nlh->nlmsg_flags & NLM_F_ACK_TLVS))
- return 1;
+ return ret;
ynl_attr_for_each(attr, nlh, sizeof(int)) {
switch (ynl_attr_type(attr)) {
@@ -68,10 +81,10 @@ static int nl_get_extack(char *buf, size_t n, struct ext_ack *ea)
}
}
- return 2;
+ return FOUND_EXTACK;
}
- return 0;
+ return ret;
}
static const struct {
@@ -99,9 +112,9 @@ static const struct {
TEST(dump_extack)
{
int netlink_sock;
+ int i, cnt, ret;
char buf[8192];
int one = 1;
- int i, cnt;
ssize_t n;
netlink_sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
@@ -118,7 +131,7 @@ TEST(dump_extack)
ASSERT_EQ(n, 0);
/* Dump so many times we fill up the buffer */
- cnt = 64;
+ cnt = 80;
for (i = 0; i < cnt; i++) {
n = send(netlink_sock, &dump_neigh_bad,
sizeof(dump_neigh_bad), 0);
@@ -140,10 +153,20 @@ TEST(dump_extack)
}
ASSERT_GE(n, (ssize_t)sizeof(struct nlmsghdr));
- EXPECT_EQ(nl_get_extack(buf, n, &ea), 2);
+ ret = nl_get_extack(buf, n, &ea);
+ /* Once we fill the buffer we'll see one ENOBUFS followed
+ * by a number of EBUSYs. Then the last recv() will finally
+ * trigger and complete the dump.
+ */
+ if (ret == FOUND_ERR && (ea.err == ENOBUFS || ea.err == EBUSY))
+ continue;
+ EXPECT_EQ(ret, FOUND_EXTACK);
+ EXPECT_EQ(ea.err, EINVAL);
EXPECT_EQ(ea.attr_offs,
sizeof(struct nlmsghdr) + sizeof(struct ndmsg));
}
+ /* Make sure last message was a full DONE+extack */
+ EXPECT_EQ(ret, FOUND_EXTACK);
}
static const struct {
--
2.51.0
The arm64 Guarded Control Stack (GCS) feature provides support for
hardware protected stacks of return addresses, intended to provide
hardening against return oriented programming (ROP) attacks and to make
it easier to gather call stacks for applications such as profiling.
When GCS is active a secondary stack called the Guarded Control Stack is
maintained, protected with a memory attribute which means that it can
only be written with specific GCS operations. The current GCS pointer
can not be directly written to by userspace. When a BL is executed the
value stored in LR is also pushed onto the GCS, and when a RET is
executed the top of the GCS is popped and compared to LR with a fault
being raised if the values do not match. GCS operations may only be
performed on GCS pages, a data abort is generated if they are not.
The combination of hardware enforcement and lack of extra instructions
in the function entry and exit paths should result in something which
has less overhead and is more difficult to attack than a purely software
implementation like clang's shadow stacks.
This series implements support for managing GCS for KVM guests, it also
includes a fix for S1PIE which has also been sent separately as this
feature is a dependency for GCS. It is based on:
https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/gcs
Signed-off-by: Mark Brown <broonie(a)kernel.org>
---
Changes in v15:
- Rebase onto v6.17-rc1.
- Link to v14: https://lore.kernel.org/r/20241005-arm64-gcs-v14-0-59060cd6092b@kernel.org
Changes in v14:
- Rebase onto arm64/for-next/gcs which includes all the non-KVM support.
- Manage the fine grained traps for GCS instructions.
- Manage PSTATE.EXLOCK when delivering exceptions to KVM guests.
- Link to v13: https://lore.kernel.org/r/20241001-arm64-gcs-v13-0-222b78d87eee@kernel.org
Changes in v13:
- Rebase onto v6.12-rc1.
- Allocate VM_HIGH_ARCH_6 since protection keys used all the existing
bits.
- Implement mm_release() and free transparently allocated GCSs there.
- Use bit 32 of AT_HWCAP for GCS due to AT_HWCAP2 being filled.
- Since we now only set GCSCRE0_EL1 on change ensure that it is
initialised with GCSPR_EL0 accessible to EL0.
- Fix OOM handling on thread copy.
- Link to v12: https://lore.kernel.org/r/20240829-arm64-gcs-v12-0-42fec947436a@kernel.org
Changes in v12:
- Clarify and simplify the signal handling code so we work with the
register state.
- When checking for write aborts to shadow stack pages ensure the fault
is a data abort.
- Depend on !UPROBES.
- Comment cleanups.
- Link to v11: https://lore.kernel.org/r/20240822-arm64-gcs-v11-0-41b81947ecb5@kernel.org
Changes in v11:
- Remove the dependency on the addition of clone3() support for shadow
stacks, rebasing onto v6.11-rc3.
- Make ID_AA64PFR1_EL1.GCS writeable in KVM.
- Hide GCS registers when GCS is not enabled for KVM guests.
- Require HCRX_EL2.GCSEn if booting at EL1.
- Require that GCSCR_EL1 and GCSCRE0_EL1 be initialised regardless of
if we boot at EL2 or EL1.
- Remove some stray use of bit 63 in signal cap tokens.
- Warn if we see a GCS with VM_SHARED.
- Remove rdundant check for VM_WRITE in fault handling.
- Cleanups and clarifications in the ABI document.
- Clean up and improve documentation of some sync placement.
- Only set the EL0 GCS mode if it's actually changed.
- Various minor fixes and tweaks.
- Link to v10: https://lore.kernel.org/r/20240801-arm64-gcs-v10-0-699e2bd2190b@kernel.org
Changes in v10:
- Fix issues with THP.
- Tighten up requirements for initialising GCSCR*.
- Only generate GCS signal frames for threads using GCS.
- Only context switch EL1 GCS registers if S1PIE is enabled.
- Move context switch of GCSCRE0_EL1 to EL0 context switch.
- Make GCS registers unconditionally visible to userspace.
- Use FHU infrastructure.
- Don't change writability of ID_AA64PFR1_EL1 for KVM.
- Remove unused arguments from alloc_gcs().
- Typo fixes.
- Link to v9: https://lore.kernel.org/r/20240625-arm64-gcs-v9-0-0f634469b8f0@kernel.org
Changes in v9:
- Rebase onto v6.10-rc3.
- Restructure and clarify memory management fault handling.
- Fix up basic-gcs for the latest clone3() changes.
- Convert to newly merged KVM ID register based feature configuration.
- Fixes for NV traps.
- Link to v8: https://lore.kernel.org/r/20240203-arm64-gcs-v8-0-c9fec77673ef@kernel.org
Changes in v8:
- Invalidate signal cap token on stack when consuming.
- Typo and other trivial fixes.
- Don't try to use process_vm_write() on GCS, it intentionally does not
work.
- Fix leak of thread GCSs.
- Rebase onto latest clone3() series.
- Link to v7: https://lore.kernel.org/r/20231122-arm64-gcs-v7-0-201c483bd775@kernel.org
Changes in v7:
- Rebase onto v6.7-rc2 via the clone3() patch series.
- Change the token used to cap the stack during signal handling to be
compatible with GCSPOPM.
- Fix flags for new page types.
- Fold in support for clone3().
- Replace copy_to_user_gcs() with put_user_gcs().
- Link to v6: https://lore.kernel.org/r/20231009-arm64-gcs-v6-0-78e55deaa4dd@kernel.org
Changes in v6:
- Rebase onto v6.6-rc3.
- Add some more gcsb_dsync() barriers following spec clarifications.
- Due to ongoing discussion around clone()/clone3() I've not updated
anything there, the behaviour is the same as on previous versions.
- Link to v5: https://lore.kernel.org/r/20230822-arm64-gcs-v5-0-9ef181dd6324@kernel.org
Changes in v5:
- Don't map any permissions for user GCSs, we always use EL0 accessors
or use a separate mapping of the page.
- Reduce the standard size of the GCS to RLIMIT_STACK/2.
- Enforce a PAGE_SIZE alignment requirement on map_shadow_stack().
- Clarifications and fixes to documentation.
- More tests.
- Link to v4: https://lore.kernel.org/r/20230807-arm64-gcs-v4-0-68cfa37f9069@kernel.org
Changes in v4:
- Implement flags for map_shadow_stack() allowing the cap and end of
stack marker to be enabled independently or not at all.
- Relax size and alignment requirements for map_shadow_stack().
- Add more blurb explaining the advantages of hardware enforcement.
- Link to v3: https://lore.kernel.org/r/20230731-arm64-gcs-v3-0-cddf9f980d98@kernel.org
Changes in v3:
- Rebase onto v6.5-rc4.
- Add a GCS barrier on context switch.
- Add a GCS stress test.
- Link to v2: https://lore.kernel.org/r/20230724-arm64-gcs-v2-0-dc2c1d44c2eb@kernel.org
Changes in v2:
- Rebase onto v6.5-rc3.
- Rework prctl() interface to allow each bit to be locked independently.
- map_shadow_stack() now places the cap token based on the size
requested by the caller not the actual space allocated.
- Mode changes other than enable via ptrace are now supported.
- Expand test coverage.
- Various smaller fixes and adjustments.
- Link to v1: https://lore.kernel.org/r/20230716-arm64-gcs-v1-0-bf567f93bba6@kernel.org
---
Mark Brown (6):
arm64/gcs: Ensure FGTs for EL1 GCS instructions are disabled
KVM: arm64: Manage GCS access and registers for guests
KVM: arm64: Forward GCS exceptions to nested guests
KVM: arm64: Set PSTATE.EXLOCK when entering an exception
KVM: arm64: Allow GCS to be enabled for guests
KVM: selftests: arm64: Add GCS registers to get-reg-list
arch/arm64/include/asm/el2_setup.h | 4 +++
arch/arm64/include/asm/kvm_emulate.h | 3 ++
arch/arm64/include/asm/kvm_host.h | 14 +++++++++
arch/arm64/include/asm/vncr_mapping.h | 2 ++
arch/arm64/include/uapi/asm/ptrace.h | 1 +
arch/arm64/kvm/handle_exit.c | 14 +++++++--
arch/arm64/kvm/hyp/exception.c | 37 ++++++++++++++++++++++++
arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 31 ++++++++++++++++++++
arch/arm64/kvm/hyp/vhe/sysreg-sr.c | 10 +++++++
arch/arm64/kvm/sys_regs.c | 32 ++++++++++++++++++--
tools/testing/selftests/kvm/arm64/get-reg-list.c | 12 ++++++++
11 files changed, 155 insertions(+), 5 deletions(-)
---
base-commit: 8f5ae30d69d7543eee0d70083daf4de8fe15d585
change-id: 20230303-arm64-gcs-e311ab0d8729
Best regards,
--
Mark Brown <broonie(a)kernel.org>
+lists
Please keep discussions on-list unless there's something that can't/shouldn't be
posted publicly, e.g. for confidentiality or security reasons.
On Tue, Sep 02, 2025, Faruqui, Aqib wrote:
> I suppose a fix for blindly using PAGE_SIZE in subsequent macros:
>
> #ifdef PAGE_SIZE
> #undef PAGE_SIZE
> #endif
> #define PAGE_SIZE (1ULL << PAGE_SHIFT)
>
> Is no better and is instead blindly suppressing the compiler's redefinition warning.
>
> I'm having trouble finding what causes the conflict, any advice here?
Maybe try a newer compiler? E.g. gcc-14.2 will spit out the exact location of the
previous definition.
In file included from include/x86/svm_util.h:13,
from include/x86/sev.h:15,
from lib/x86/sev.c:5:
include/x86/processor.h:373:9: error: "PAGE_SIZE" redefined [-Werror]
373 | #define PAGE_SIZE (1ULL << PAGE_SHIFT)
| ^~~~~~~~~
include/x86/processor.h:370:9: note: this is the location of the previous definition
370 | #define PAGE_SIZE BIT(12)
| ^~~~~~~~~
Fix to use the return value of the function 'chdir("/")' and check if the
return is either 0 (ok) or 1 (not ok, so the test stops).
The patch fies the solves the following errors:
mount-notify_test.c:468:17: warning: ignoring return value of ‘chdir’
declared with attribute ‘warn_unused_result’ [-Wunused-result]
468 | chdir("/");
mount-notify_test_ns.c:489:17: warning: ignoring return value of
‘chdir’ declared with attribute ‘warn_unused_result’ [-Wunused-
result]
489 | chdir("/");
To reproduce the issue, use the command:
make kselftest TARGET=filesystems/statmount
Signed-off-by: Alessandro Zanni <alessandro.zanni87(a)gmail.com>
Reviewed-by: Jan Kara <jack(a)suse.cz>
---
.../selftests/filesystems/mount-notify/mount-notify_test.c | 2 +-
.../selftests/filesystems/mount-notify/mount-notify_test_ns.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
index 5a3b0ace1a88..a7f899599d52 100644
--- a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
+++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
@@ -458,7 +458,7 @@ TEST_F(fanotify, rmdir)
ASSERT_GE(ret, 0);
if (ret == 0) {
- chdir("/");
+ ASSERT_EQ(0, chdir("/"));
unshare(CLONE_NEWNS);
mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL);
umount2("/a", MNT_DETACH);
diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c
index d91946e69591..dc9eb3087a1a 100644
--- a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c
+++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c
@@ -486,7 +486,7 @@ TEST_F(fanotify, rmdir)
ASSERT_GE(ret, 0);
if (ret == 0) {
- chdir("/");
+ ASSERT_EQ(0, chdir("/"));
unshare(CLONE_NEWNS);
mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL);
umount2("/a", MNT_DETACH);
--
2.43.0
Fix to use the return value of the function 'chdir("/")' and check if the
return is either 0 (ok) or 1 (not ok, so the test stops).
The patch fies the solves the following errors:
mount-notify_test.c:468:17: warning: ignoring return value of ‘chdir’
declared with attribute ‘warn_unused_result’ [-Wunused-result]
468 | chdir("/");
mount-notify_test_ns.c:489:17: warning: ignoring return value of
‘chdir’ declared with attribute ‘warn_unused_result’ [-Wunused-
result]
489 | chdir("/");
To reproduce the issue, use the command:
make kselftest TARGET=filesystems/statmount
Signed-off-by: Alessandro Zanni <alessandro.zanni87(a)gmail.com>
---
.../selftests/filesystems/mount-notify/mount-notify_test.c | 2 +-
.../selftests/filesystems/mount-notify/mount-notify_test_ns.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
index 5a3b0ace1a88..a7f899599d52 100644
--- a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
+++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
@@ -458,7 +458,7 @@ TEST_F(fanotify, rmdir)
ASSERT_GE(ret, 0);
if (ret == 0) {
- chdir("/");
+ ASSERT_EQ(0, chdir("/"));
unshare(CLONE_NEWNS);
mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL);
umount2("/a", MNT_DETACH);
diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c
index d91946e69591..dc9eb3087a1a 100644
--- a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c
+++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c
@@ -486,7 +486,7 @@ TEST_F(fanotify, rmdir)
ASSERT_GE(ret, 0);
if (ret == 0) {
- chdir("/");
+ ASSERT_EQ(0, chdir("/"));
unshare(CLONE_NEWNS);
mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL);
umount2("/a", MNT_DETACH);
--
2.43.0