Add parentheses around loopback address check to fix up logic and make
the socket state filter configurable for the TCP socket iterators.
Iterators can skip the socket state check by setting ss to 0.
Signed-off-by: Jordan Rife <jordan@jrife.io>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Prepare to test TCP socket iteration over both listening and established
sockets by allowing the BPF iterator programs to skip the port check.
Signed-off-by: Jordan Rife <jordan@jrife.io>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Replicate the set of test cases used for UDP socket iterators to test
similar scenarios for TCP listening sockets.
Signed-off-by: Jordan Rife <jordan@jrife.io>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
The selftest doesn't cover this error path:
scratch = *raw_cpu_ptr(m->scratch);
if (unlikely(!scratch)) { // here
cover this too.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Previous patch added a new clash resolution test case.
Also use this during conntrack resize stress test in addition
to icmp ping flood.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add a dedicated test to exercise conntrack clash resolution path.
Test program emits 128 identical udp packets in parallel, then reads
back replies from socat echo server.
Also check (via conntrack -S) that the clash path was hit at least once.
Due to the racy nature of the test its possible that despite the
threaded program all packets were processed in-order or on same cpu,
emit a SKIP warning in this case.
Two tests are added:
- one to test the simpler, non-nat case
- one to exercise clash resolution where packets
might have different nat transformations attached to them.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Extend the resize test:
- continuously dump table both via /proc and ctnetlink interfaces while
table is resized in a loop.
- if socat is available, send udp packets in additon to ping requests.
- increase/decrease the icmp and udp timeouts while resizes are happening.
This makes sure we also exercise the 'ct has expired' check that happens
on conntrack lookup.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add a python-written DAMON sysfs functionality selftest. It sets DAMON
parameters using Python module _damon_sysfs, reads updated kernel internal
DAMON status and parameters using a 'drgn' script, namely
drgn_dump_damon_status.py, and compare if the resulted DAMON internal
status is as expected. The test is very minimum at the moment.
Link: https://lkml.kernel.org/r/20250628160428.53115-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "selftests/damon: add python and drgn based DAMON sysfs
functionality tests".
DAMON sysfs interface is the bridge between the user space and the kernel
space for DAMON parameters. There is no good and simple test to see if
the parameters are set as expected. Existing DAMON selftests therefore
test end-to-end features. For example, damos_quota_goal.py runs a DAMOS
scheme with quota goal set against a test program running an artificial
access pattern, and see if the result is as expected. Such tests cover
only a few part of DAMON. Adding more tests is also complicated.
Finally, the reliability of the test itself on different systems is bad.
'drgn' is a tool that can extract kernel internal data structures like
DAMON parameters. Add a test that passes specific DAMON parameters via
DAMON sysfs reusing _damon_sysfs.py, extract resulting DAMON parameters
via 'drgn', and compare those. Note that this test is not adding
exhaustive tests of all DAMON parameters and input combinations but very
basic things. Advancing the test infrastructure and adding more tests are
future works.
This patch (of 6):
'drgn' is a useful tool for extracting kernel internal data structures
such as DAMON's parameter and running status. Add a 'drgn' script that
extracts such DAMON internal data at runtime, for using it as a tool for
seeing if a test input has made expected results in the kernel.
The script saves or prints out the DAMON internal data as a json file or
string. This is for making use of it not very depends on 'drgn'. If
'drgn' is not available on a test setup and we find alternative tools for
doing that, the json-based tests can be updated to use an alternative tool
in future.
Note that the script is tested with 'drgn v0.0.22'.
Link: https://lkml.kernel.org/r/20250628160428.53115-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20250628160428.53115-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The test_kmem_dead_cgroups test currently assumes that RCU and
memory reclaim will complete within 5 seconds. In some environments
this timeout may be insufficient, leading to spurious test failures.
This patch introduces max_time set to 20 which is then used in the
test. After 5th sec the debug message is printed to indicate the
cleanup is still ongoing.
In the system under test with 16 CPUs the original test was failing
most of the time and the cleanup time took usually approx. 6sec.
Further tests were conducted with and without do_rcu_barrier and the
results (respectively) are as follow:
quantiles 0 0.25 0.5 0.75 1
1 2 3 8 20 (mean = 4.7667)
3 5 8 8 20 (mean = 7.6667)
Acked-by: Michal Koutny <mkoutny@suse.com>
Signed-off-by: Sebastian Chlad <sebastian.chlad@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The iou-zcrx selftest currently runs the server on the remote host
and the client on the local host. This commit flips the endpoints
such that server runs on localhost and client on remote.
This change brings the iou-zcrx selftest in convention with other
selftests.
Drive-by fix for a missing import exception that happens when the
network interface has less than 2 combined channels.
Test plan: ran iou-zcrx.py selftest between 2 physical machines
Signed-off-by: Vishwanath Seshagiri <vishs@fb.com>
Link: https://patch.msgid.link/20250710165337.614159-1-vishs@meta.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Cross-merge networking fixes after downstream PR (net-6.16-rc6-2).
No conflicts.
Adjacent changes:
drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
c701574c54 ("wifi: mt76: mt7925: fix invalid array index in ssid assignment during hw scan")
b3a431fe2e ("wifi: mt76: mt7925: fix off by one in mt7925_mcu_hw_scan()")
drivers/net/wireless/mediatek/mt76/mt7996/mac.c
62da647a2b ("wifi: mt76: mt7996: Add MLO support to mt7996_tx_check_aggr()")
dc66a129ad ("wifi: mt76: add a wrapper for wcid access with validation")
drivers/net/wireless/mediatek/mt76/mt7996/main.c
3dd6f67c66 ("wifi: mt76: Move RCU section in mt7996_mcu_add_rate_ctrl()")
8989d8e90f ("wifi: mt76: mt7996: Do not set wcid.sta to 1 in mt7996_mac_sta_event()")
net/mac80211/cfg.c
58fcb1b428 ("wifi: mac80211: reject VHT opmode for unsupported channel widths")
037dc18ac3 ("wifi: mac80211: add support for storing station S1G capabilities")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The auto scaling on create creation used to automatically assign the new
hash because there was the private hash was unused and could be replaced
right away.
This is already racy because if the private hash is in use by a thread
then the visibile resize will be delayed. With the upcoming change to
wait for a RCU grace period before the hash can be assigned, the test
will always fail.
If the reported number of hash buckets is not updated after an
auto scaling event, block on an acquired lock with a timeout. The timeout
is the delay to wait towards a grace period and locking and a locked
pthread_mutex_t ensure that glibc calls into kernel using futex
operation which will assign new private hash if available.
This will retry every 100ms up to 2 seconds in total.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250710110011.384614-2-bigeasy@linutronix.de
I got the following warning when writing other tests:
+ handle_test_result_pass 'bond 802.3ad' '(lacp_active off)'
+ local 'test_name=bond 802.3ad'
+ shift
+ local 'opt_str=(lacp_active off)'
+ shift
+ log_test_result 'bond 802.3ad' '(lacp_active off)' ' OK '
+ local 'test_name=bond 802.3ad'
+ shift
+ local 'opt_str=(lacp_active off)'
+ shift
+ local 'result= OK '
+ shift
+ local retmsg=
+ shift
/net/tools/testing/selftests/net/forwarding/../lib.sh: line 315: shift: shift count out of range
This happens because an extra shift is executed even after all arguments
have been consumed. Remove the last shift in log_test_result() to avoid
this warning.
Fixes: a923af1cee ("selftests: forwarding: Convert log_test() to recognize RET values")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Link: https://patch.msgid.link/20250709091244.88395-1-liuhangbin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The previous patch fixes a bug that prevented the creation of the
default IPv6 multicast route (ff00::/8) for some GRE devices. Now let's
extend the GRE IPv6 selftests to cover this case.
Also, rename check_ipv6_ll_addr() to check_ipv6_device_config() and
adapt comments and script output to take into account the fact that
we're not limited to link-local address generation.
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/65a89583bde3bf866a1922c2e5158e4d72c520e2.1752070620.git.gnault@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Test reading RXFH fields over IOCTL and netlink.
# ./tools/testing/selftests/drivers/net/hw/rss_api.py
TAP version 13
1..3
ok 1 rss_api.test_rxfh_indir_ntf
ok 2 rss_api.test_rxfh_indir_ctx_ntf
ok 3 rss_api.test_rxfh_fields
# Totals: pass:3 fail:0 xfail:0 xpass:0 skip:0 error:0
Link: https://patch.msgid.link/20250708220640.2738464-6-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The step_after_suspend_test verifies that the system successfully
suspended and resumed by setting a timerfd and checking whether the
timer fully expired. However, this method is unreliable due to timing
races.
In practice, the system may take time to enter suspend, during which the
timer may expire just before or during the transition. As a result,
the remaining time after resume may show non-zero nanoseconds, even if
suspend/resume completed successfully. This leads to false test failures.
Replace the timer-based check with a read from
/sys/power/suspend_stats/success. This counter is incremented only
after a full suspend/resume cycle, providing a reliable and race-free
indicator.
Also remove the unused file descriptor for /sys/power/state, which
remained after switching to a system() call to trigger suspend [1].
[1] https://lore.kernel.org/all/20240930224025.2858767-1-yifei.l.liu@oracle.com/
Link: https://lore.kernel.org/r/20250626191626.36794-1-moonhee.lee.ca@gmail.com
Fixes: c66be905cd ("selftests: breakpoints: use remaining time to check if suspend succeed")
Signed-off-by: Moon Hee Lee <moonhee.lee.ca@gmail.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Pull networking fixes from Paolo Abeni:
"Including fixes from Bluetooth.
Current release - regressions:
- tcp: refine sk_rcvbuf increase for ooo packets
- bluetooth: fix attempting to send HCI_Disconnect to BIS handle
- rxrpc: fix over large frame size warning
- eth: bcmgenet: initialize u64 stats seq counter
Previous releases - regressions:
- tcp: correct signedness in skb remaining space calculation
- sched: abort __tc_modify_qdisc if parent class does not exist
- vsock: fix transport_{g2h,h2g} TOCTOU
- rxrpc: fix bug due to prealloc collision
- tipc: fix use-after-free in tipc_conn_close().
- bluetooth: fix not marking Broadcast Sink BIS as connected
- phy: qca808x: fix WoL issue by utilizing at8031_set_wol()
- eth: am65-cpsw-nuss: fix skb size by accounting for skb_shared_info
Previous releases - always broken:
- netlink: fix wraparounds of sk->sk_rmem_alloc.
- atm: fix infinite recursive call of clip_push().
- eth:
- stmmac: fix interrupt handling for level-triggered mode in DWC_XGMAC2
- rtsn: fix a null pointer dereference in rtsn_probe()"
* tag 'net-6.16-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (37 commits)
net/sched: sch_qfq: Fix null-deref in agg_dequeue
rxrpc: Fix oops due to non-existence of prealloc backlog struct
rxrpc: Fix bug due to prealloc collision
MAINTAINERS: remove myself as netronome maintainer
selftests/net: packetdrill: add tcp_ooo-before-and-after-accept.pkt
tcp: refine sk_rcvbuf increase for ooo packets
net/sched: Abort __tc_modify_qdisc if parent class does not exist
net: ethernet: ti: am65-cpsw-nuss: Fix skb size by accounting for skb_shared_info
net: thunderx: avoid direct MTU assignment after WRITE_ONCE()
selftests/tc-testing: Create test case for UAF scenario with DRR/NETEM/BLACKHOLE chain
atm: clip: Fix NULL pointer dereference in vcc_sendmsg()
atm: clip: Fix infinite recursive call of clip_push().
atm: clip: Fix memory leak of struct clip_vcc.
atm: clip: Fix potential null-ptr-deref in to_atmarpd().
net: phy: smsc: Fix link failure in forced mode with Auto-MDIX
net: phy: smsc: Force predictable MDI-X state on LAN87xx
net: phy: smsc: Fix Auto-MDIX configuration when disabled by strap
net: stmmac: Fix interrupt handling for level-triggered mode in DWC_XGMAC2
rxrpc: Fix over large frame size warning
net: airoha: Fix an error handling path in airoha_probe()
...
Pull KVM fixes from Paolo Bonzini:
"Many patches, pretty much all of them small, that accumulated while I
was on vacation.
ARM:
- Remove the last leftovers of the ill-fated FPSIMD host state
mapping at EL2 stage-1
- Fix unexpected advertisement to the guest of unimplemented S2 base
granule sizes
- Gracefully fail initialising pKVM if the interrupt controller isn't
GICv3
- Also gracefully fail initialising pKVM if the carveout allocation
fails
- Fix the computing of the minimum MMIO range required for the host
on stage-2 fault
- Fix the generation of the GICv3 Maintenance Interrupt in nested
mode
x86:
- Reject SEV{-ES} intra-host migration if one or more vCPUs are
actively being created, so as not to create a non-SEV{-ES} vCPU in
an SEV{-ES} VM
- Use a pre-allocated, per-vCPU buffer for handling de-sparsification
of vCPU masks in Hyper-V hypercalls; fixes a "stack frame too
large" issue
- Allow out-of-range/invalid Xen event channel ports when configuring
IRQ routing, to avoid dictating a specific ioctl() ordering to
userspace
- Conditionally reschedule when setting memory attributes to avoid
soft lockups when userspace converts huge swaths of memory to/from
private
- Add back MWAIT as a required feature for the MONITOR/MWAIT selftest
- Add a missing field in struct sev_data_snp_launch_start that
resulted in the guest-visible workarounds field being filled at the
wrong offset
- Skip non-canonical address when processing Hyper-V PV TLB flushes
to avoid VM-Fail on INVVPID
- Advertise supported TDX TDVMCALLs to userspace
- Pass SetupEventNotifyInterrupt arguments to userspace
- Fix TSC frequency underflow"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: x86: avoid underflow when scaling TSC frequency
KVM: arm64: Remove kvm_arch_vcpu_run_map_fp()
KVM: arm64: Fix handling of FEAT_GTG for unimplemented granule sizes
KVM: arm64: Don't free hyp pages with pKVM on GICv2
KVM: arm64: Fix error path in init_hyp_mode()
KVM: arm64: Adjust range correctly during host stage-2 faults
KVM: arm64: nv: Fix MI line level calculation in vgic_v3_nested_update_mi()
KVM: x86/hyper-v: Skip non-canonical addresses during PV TLB flush
KVM: SVM: Add missing member in SNP_LAUNCH_START command structure
Documentation: KVM: Fix unexpected unindent warnings
KVM: selftests: Add back the missing check of MONITOR/MWAIT availability
KVM: Allow CPU to reschedule while setting per-page memory attributes
KVM: x86/xen: Allow 'out of range' event channel ports in IRQ routing table.
KVM: x86/hyper-v: Use preallocated per-vCPU buffer for de-sparsified vCPU masks
KVM: SVM: Initialize vmsa_pa in VMCB to INVALID_PAGE if VMSA page is NULL
KVM: SVM: Reject SEV{-ES} intra host migration if vCPU creation is in-flight
KVM: TDX: Report supported optional TDVMCALLs in TDX capabilities
KVM: TDX: Exit to userspace for SetupEventNotifyInterrupt
hid-tools 0.10 fixes one inconvenience introduced by
commit 6a9e76f75c ("HID: multitouch: Disable touchpad
on firmware level while not in use")
This change added a new callback when a hid-nultitouch device is opened
or closed to put the underlying device into a given operating mode.
However, in the test cases, that means that while the single threaded
test is run, it opens the device but has to react to the device while
the open() is still running. hid-tools now implements a minimal thread
to circumvent this.
This makes the HID kernel tests in sync with hid-tools 0.10.
This has the net effect of running the full HID python testsuite in 6
minutes instead of 1 hour.
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Link: https://patch.msgid.link/20250709-wip-fix-ci-v1-3-b7df4c271cf8@kernel.org
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Instead of backporting one by one each commits, let's pull them in bulk
and refer to the hid-tools project for a detailed history.
The short summary is:
- make use of dataclass when possible, to avoid tuples
- wacom: remove unused uhdev parameter
- various small fixes not worth mentioning
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Link: https://patch.msgid.link/20250709-wip-fix-ci-v1-2-b7df4c271cf8@kernel.org
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Some systems (e.g. minimal or real-time kernels) may not enable
Transparent Hugepages (THP), causing MADV_HUGEPAGE to return EINVAL. This
patch introduces a runtime check using the existing THP sysfs interface
and skips the hugepage merging test (`-H`) when THP is not available.
To avoid those failures:
# -----------------------------
# running ./ksm_tests -H -s 100
# -----------------------------
# ksm_tests: MADV_HUGEPAGE: Invalid argument
# [FAIL]
not ok 1 ksm_tests -H -s 100 # exit=2
# --------------------
# running ./khugepaged
# --------------------
# Reading PMD pagesize failed# [FAIL]
not ok 1 khugepaged # exit=1
# --------------------
# running ./soft-dirty
# --------------------
# TAP version 13
# 1..15
# ok 1 Test test_simple
# ok 2 Test test_vma_reuse dirty bit of allocated page
# ok 3 Test test_vma_reuse dirty bit of reused address page
# Bail out! Reading PMD pagesize failed# Planned tests != run tests (15 != 3)
# # Totals: pass:3 fail:0 xfail:0 xpass:0 skip:0 error:0
# [FAIL]
not ok 1 soft-dirty # exit=1
# SUMMARY: PASS=0 SKIP=0 FAIL=1
# -------------------
# running ./migration
# -------------------
# TAP version 13
# 1..3
# # Starting 3 tests from 1 test cases.
# # RUN migration.private_anon ...
# # OK migration.private_anon
# ok 1 migration.private_anon
# # RUN migration.shared_anon ...
# # OK migration.shared_anon
# ok 2 migration.shared_anon
# # RUN migration.private_anon_thp ...
# # migration.c:196:private_anon_thp:Expected madvise(ptr, TWOMEG, MADV_HUGEPAGE) (-1) == 0 (0)
# # private_anon_thp: Test terminated by assertion
# # FAIL migration.private_anon_thp
# not ok 3 migration.private_anon_thp
# # FAILED: 2 / 3 tests passed.
# # Totals: pass:2 fail:1 xfail:0 xpass:0 skip:0 error:0
# [FAIL]
not ok 1 migration # exit=1
It's true that CONFIG_TRANSPARENT_HUGEPAGE=y is explicitly enabled in
tools/testing/selftests/mm/config, so ideally the runtime environment
should also support THP.
However, in practice, we've found that on some systems:
- THP is disabled at boot time (transparent_hugepage=never)
- Or manually disabled via sysfs
- Or unavailable in RT kernels, containers, or minimal CI environments
In these cases, the test will fail with EINVAL on madvise(MADV_HUGEPAGE),
even though the kernel config is correct.
To make the test suite more robust and avoid false negatives, this patch
adds a runtime check for /sys/kernel/mm/transparent_hugepage/enabled.
If THP is not available, the hugepage test (-H) is skipped with a clear
message.
Link: https://lkml.kernel.org/r/20250624032748.393836-1-liwang@redhat.com
Signed-off-by: Li Wang <liwang@redhat.com>
Cc: Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Keith Lucas <keith.lucas@oracle.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The current implementation of test_unmerge_uffd_wp() explicitly sets
`uffdio_api.features = UFFD_FEATURE_PAGEFAULT_FLAG_WP` before calling
UFFDIO_API. This can cause the ioctl() call to fail with EINVAL on
kernels that do not support UFFD-WP, leading the test to fail
unnecessarily:
# ------------------------------
# running ./ksm_functional_tests
# ------------------------------
# TAP version 13
# 1..9
# # [RUN] test_unmerge
# ok 1 Pages were unmerged
# # [RUN] test_unmerge_zero_pages
# ok 2 KSM zero pages were unmerged
# # [RUN] test_unmerge_discarded
# ok 3 Pages were unmerged
# # [RUN] test_unmerge_uffd_wp
# not ok 4 UFFDIO_API failed <-----
# # [RUN] test_prot_none
# ok 5 Pages were unmerged
# # [RUN] test_prctl
# ok 6 Setting/clearing PR_SET_MEMORY_MERGE works
# # [RUN] test_prctl_fork
# # No pages got merged
# # [RUN] test_prctl_fork_exec
# ok 7 PR_SET_MEMORY_MERGE value is inherited
# # [RUN] test_prctl_unmerge
# ok 8 Pages were unmerged
# Bail out! 1 out of 8 tests failed
# # Planned tests != run tests (9 != 8)
# # Totals: pass:7 fail:1 xfail:0 xpass:0 skip:0 error:0
# [FAIL]
This patch improves compatibility and robustness of the UFFD-WP test
(test_unmerge_uffd_wp) by correctly implementing the UFFDIO_API two-step
handshake as recommended by the userfaultfd(2) man page.
Key changes:
1. Use features=0 in the initial UFFDIO_API call to query supported
feature bits, rather than immediately requesting WP support.
2. Skip the test gracefully if:
- UFFDIO_API fails with EINVAL (e.g. unsupported API version), or
- UFFD_FEATURE_PAGEFAULT_FLAG_WP is not advertised by the kernel.
3. Close the initial userfaultfd and create a new one before enabling
the required feature, since UFFDIO_API can only be called once per fd.
4. Improve diagnostics by distinguishing between expected and unexpected
failures, using strerror() to report errors.
This ensures the test behaves correctly across a wider range of kernel
versions and configurations, while preserving the intended behavior on
kernels that support UFFD-WP.
[liwang@redhat.com: fail the test if sys_userfaultfd() fails, per David]
Link: https://lkml.kernel.org/r/20250625004645.400520-1-liwang@redhat.com
Link: https://lkml.kernel.org/r/20250624042411.395285-1-liwang@redhat.com
Signed-off-by: Li Wang <liwang@redhat.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Keith Lucas <keith.lucas@oracle.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Li Wang <liwang@redhat.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
