December 2024 - Linux-kselftest-mirror

[PATCH v5 0/2] kselftest: tmpfs: Add ksft macros and skip if no root

by Shivam Chaudhary

This version 5 patch series replace direct error handling methods with ksft macros, which provide better reporting.Currently, when the tmpfs test runs, it does not display any output if it passes,and if it fails (particularly when not run as root),it simply exits without any warning or message. This series of patch adds: 1. Add 'ksft_print_header()' and 'ksft_set_plan()' to structure test outputs more effectively. 2. Error if not run as root. 3. Replace direct error handling with 'ksft_test_result_*', 'ksft_exit_fail_msg' macros for better reporting. v4->v5: - Remove unnecessary pass messages. - Remove unnecessary use of KSFT_SKIP. - Add appropriate use of ksft_exit_fail_msg. v4 1/2: https://lore.kernel.org/all/20241105202639.1977356-2-cvam0000@gmail.com/ v4 2/2: https://lore.kernel.org/all/20241105202639.1977356-3-cvam0000@gmail.com/ v3->v4: - Start a patchset - Split patch into smaller patches to make it easy to review. Patch1 Replace 'ksft_test_result_skip' with 'KSFT_SKIP' during root run check. Patch2 Replace 'ksft_test_result_fail' with 'KSFT_SKIP' where fail does not make sense, or failure could be due to not unsupported APIs with appropriate warnings. v3: https://lore.kernel.org/all/20241028185756.111832-1-cvam0000@gmail.com/ v2->v3: - Remove extra ksft_set_plan() - Remove function for unshare() - Fix the comment style v2: https://lore.kernel.org/all/20241026191621.2860376-1-cvam0000@gmail.com/ v1->v2: - Make the commit message more clear. v1: https://lore.kernel.org/all/20241024200228.1075840-1-cvam0000@gmail.com/T/#u thanks Shivam Shivam Chaudhary (2): selftests: tmpfs: Add Test-fail if not run as root selftests: tmpfs: Add kselftest support to tmpfs .../selftests/tmpfs/bug-link-o-tmpfile.c | 60 ++++++++++++------- 1 file changed, 37 insertions(+), 23 deletions(-) -- 2.45.2

11 months

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[PATCH] selftests: acct: Add ksft_exit_fail if not running as root

by Shivam Chaudhary

If the selftest is not running as root, it should fail and give an appropriate warning to the user. This patch adds ksft_exit_fail_msg() if the test is not running as root. Logs: Before change: TAP version 13 1..1 ok 1 # SKIP This test needs root to run! After change: TAP version 13 1..1 Bail out! Error : Need to run as root# Planned tests != run tests (1 != 0) Totals: pass:0 fail:0 xfail:0 xpass:0 skip:0 error:0 Signed-off-by: Shivam Chaudhary <cvam0000(a)gmail.com> --- tools/testing/selftests/acct/acct_syscall.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/tools/testing/selftests/acct/acct_syscall.c b/tools/testing/selftests/acct/acct_syscall.c index e44e8fe1f4a3..7c65deef54e3 100644 --- a/tools/testing/selftests/acct/acct_syscall.c +++ b/tools/testing/selftests/acct/acct_syscall.c @@ -24,8 +24,7 @@ int main(void) // Check if test is run a root if (geteuid()) { - ksft_test_result_skip("This test needs root to run!\n"); - return 1; + ksft_exit_fail_msg("Error : Need to run as root"); } // Create file to log closed processes -- 2.45.2

11 months

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1
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[PATCH RFT v13 0/8] fork: Support shadow stacks in clone3()

by Mark Brown

The kernel has recently added support for shadow stacks, currently x86 only using their CET feature but both arm64 and RISC-V have equivalent features (GCS and Zicfiss respectively), I am actively working on GCS[1]. With shadow stacks the hardware maintains an additional stack containing only the return addresses for branch instructions which is not generally writeable by userspace and ensures that any returns are to the recorded addresses. This provides some protection against ROP attacks and making it easier to collect call stacks. These shadow stacks are allocated in the address space of the userspace process. Our API for shadow stacks does not currently offer userspace any flexiblity for managing the allocation of shadow stacks for newly created threads, instead the kernel allocates a new shadow stack with the same size as the normal stack whenever a thread is created with the feature enabled. The stacks allocated in this way are freed by the kernel when the thread exits or shadow stacks are disabled for the thread. This lack of flexibility and control isn't ideal, in the vast majority of cases the shadow stack will be over allocated and the implicit allocation and deallocation is not consistent with other interfaces. As far as I can tell the interface is done in this manner mainly because the shadow stack patches were in development since before clone3() was implemented. Since clone3() is readily extensible let's add support for specifying a shadow stack when creating a new thread or process, keeping the current implicit allocation behaviour if one is not specified either with clone3() or through the use of clone(). The user must provide a shadow stack pointer, this must point to memory mapped for use as a shadow stackby map_shadow_stack() with an architecture specified shadow stack token at the top of the stack. Please note that the x86 portions of this code are build tested only, I don't appear to have a system that can run CET available to me. [1] https://lore.kernel.org/linux-arm-kernel/20241001-arm64-gcs-v13-0-222b78d87… Signed-off-by: Mark Brown <broonie(a)kernel.org> --- Changes in v13: - Rebase onto v6.13-rc1. - Link to v12: https://lore.kernel.org/r/20241031-clone3-shadow-stack-v12-0-7183eb8bee17@k… Changes in v12: - Add the regular prctl() to the userspace API document since arm64 support is queued in -next. - Link to v11: https://lore.kernel.org/r/20241005-clone3-shadow-stack-v11-0-2a6a2bd6d651@k… Changes in v11: - Rebase onto arm64 for-next/gcs, which is based on v6.12-rc1, and integrate arm64 support. - Rework the interface to specify a shadow stack pointer rather than a base and size like we do for the regular stack. - Link to v10: https://lore.kernel.org/r/20240821-clone3-shadow-stack-v10-0-06e8797b9445@k… Changes in v10: - Integrate fixes & improvements for the x86 implementation from Rick Edgecombe. - Require that the shadow stack be VM_WRITE. - Require that the shadow stack base and size be sizeof(void *) aligned. - Clean up trailing newline. - Link to v9: https://lore.kernel.org/r/20240819-clone3-shadow-stack-v9-0-962d74f99464@ke… Changes in v9: - Pull token validation earlier and report problems with an error return to parent rather than signal delivery to the child. - Verify that the top of the supplied shadow stack is VM_SHADOW_STACK. - Rework token validation to only do the page mapping once. - Drop no longer needed support for testing for signals in selftest. - Fix typo in comments. - Link to v8: https://lore.kernel.org/r/20240808-clone3-shadow-stack-v8-0-0acf37caf14c@ke… Changes in v8: - Fix token verification with user specified shadow stack. - Don't track user managed shadow stacks for child processes. - Link to v7: https://lore.kernel.org/r/20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@ke… Changes in v7: - Rebase onto v6.11-rc1. - Typo fixes. - Link to v6: https://lore.kernel.org/r/20240623-clone3-shadow-stack-v6-0-9ee7783b1fb9@ke… Changes in v6: - Rebase onto v6.10-rc3. - Ensure we don't try to free the parent shadow stack in error paths of x86 arch code. - Spelling fixes in userspace API document. - Additional cleanups and improvements to the clone3() tests to support the shadow stack tests. - Link to v5: https://lore.kernel.org/r/20240203-clone3-shadow-stack-v5-0-322c69598e4b@ke… Changes in v5: - Rebase onto v6.8-rc2. - Rework ABI to have the user allocate the shadow stack memory with map_shadow_stack() and a token. - Force inlining of the x86 shadow stack enablement. - Move shadow stack enablement out into a shared header for reuse by other tests. - Link to v4: https://lore.kernel.org/r/20231128-clone3-shadow-stack-v4-0-8b28ffe4f676@ke… Changes in v4: - Formatting changes. - Use a define for minimum shadow stack size and move some basic validation to fork.c. - Link to v3: https://lore.kernel.org/r/20231120-clone3-shadow-stack-v3-0-a7b8ed3e2acc@ke… Changes in v3: - Rebase onto v6.7-rc2. - Remove stale shadow_stack in internal kargs. - If a shadow stack is specified unconditionally use it regardless of CLONE_ parameters. - Force enable shadow stacks in the selftest. - Update changelogs for RISC-V feature rename. - Link to v2: https://lore.kernel.org/r/20231114-clone3-shadow-stack-v2-0-b613f8681155@ke… Changes in v2: - Rebase onto v6.7-rc1. - Remove ability to provide preallocated shadow stack, just specify the desired size. - Link to v1: https://lore.kernel.org/r/20231023-clone3-shadow-stack-v1-0-d867d0b5d4d0@ke… --- Mark Brown (8): arm64/gcs: Return a success value from gcs_alloc_thread_stack() Documentation: userspace-api: Add shadow stack API documentation selftests: Provide helper header for shadow stack testing fork: Add shadow stack support to clone3() selftests/clone3: Remove redundant flushes of output streams selftests/clone3: Factor more of main loop into test_clone3() selftests/clone3: Allow tests to flag if -E2BIG is a valid error code selftests/clone3: Test shadow stack support Documentation/userspace-api/index.rst | 1 + Documentation/userspace-api/shadow_stack.rst | 42 ++++ arch/arm64/include/asm/gcs.h | 8 +- arch/arm64/kernel/process.c | 8 +- arch/arm64/mm/gcs.c | 62 +++++- arch/x86/include/asm/shstk.h | 11 +- arch/x86/kernel/process.c | 2 +- arch/x86/kernel/shstk.c | 57 +++++- include/asm-generic/cacheflush.h | 11 ++ include/linux/sched/task.h | 17 ++ include/uapi/linux/sched.h | 10 +- kernel/fork.c | 96 +++++++-- tools/testing/selftests/clone3/clone3.c | 226 ++++++++++++++++++---- tools/testing/selftests/clone3/clone3_selftests.h | 65 ++++++- tools/testing/selftests/ksft_shstk.h | 98 ++++++++++ 15 files changed, 633 insertions(+), 81 deletions(-) --- base-commit: 40384c840ea1944d7c5a392e8975ed088ecf0b37 change-id: 20231019-clone3-shadow-stack-15d40d2bf536 Best regards, -- Mark Brown <broonie(a)kernel.org>

11 months

1
8
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[PATCH v1 0/2] iommufd: Fix a small bug in fault.c

by Nicolin Chen

There are a few patches in vIRQ series that rework the fault.c file. So, we should fix this before that bigger series touches the same code. And add missing coverage for IOMMU_FAULT_QUEUE_ALLOC in iommufd_fail_nth. Thanks! Nicolin Nicolin Chen (2): iommufd/fault: Fix out_fput in iommufd_fault_alloc() iommufd/selftest: Cover IOMMU_FAULT_QUEUE_ALLOC in iommufd_fail_nth drivers/iommu/iommufd/fault.c | 2 -- tools/testing/selftests/iommu/iommufd_fail_nth.c | 14 ++++++++++++++ 2 files changed, 14 insertions(+), 2 deletions(-) -- 2.43.0

11 months

3
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[PATCH] selftests/net: call sendmmsg via udpgso_bench.sh

by Kenjiro Nakayama

Currently, sendmmsg is implemented in udpgso_bench_tx.c, but it is not called by any test script. This patch adds a test for sendmmsg in udpgso_bench.sh. This allows for basic API testing and benchmarking comparisons with GSO. --- tools/testing/selftests/net/udpgso_bench.sh | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/testing/selftests/net/udpgso_bench.sh b/tools/testing/selftests/net/udpgso_bench.sh index 640bc43452fa..88fa1d53ba2b 100755 --- a/tools/testing/selftests/net/udpgso_bench.sh +++ b/tools/testing/selftests/net/udpgso_bench.sh @@ -92,6 +92,9 @@ run_udp() { echo "udp" run_in_netns ${args} + echo "udp sendmmsg" + run_in_netns ${args} -m + echo "udp gso" run_in_netns ${args} -S 0 -- 2.39.3 (Apple Git-146)

11 months

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2
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[RFC PATCH v2 0/2] KVM: guest_memfd: use write for population

by Nikita Kalyazin

As discussed in the v1 [1], with guest_memfd moving from KVM to mm, it is more practical to have a non-KVM-specific API to populate guest memory in a generic way. The series proposes using the write syscall for this purpose instead of a KVM ioctl as in the v1. The approach also has an advantage that the guest_memfd handle can be sent to another process that would be responsible for population. I also included a suggestion from Mike Day for excluding the code from compilation if AMD SEV is configured. There is a potential for refactoring of the kvm_gmem_populate to extract common parts with the write. I did not do that in this series yet to keep it clear what the write would do and get feedback on whether write's behaviour is sensible. Nikita [1]: https://lore.kernel.org/kvm/20241024095429.54052-1-kalyazin@amazon.com/T/ Nikita Kalyazin (2): KVM: guest_memfd: add generic population via write KVM: selftests: update guest_memfd write tests .../testing/selftests/kvm/guest_memfd_test.c | 85 +++++++++++++++++-- virt/kvm/guest_memfd.c | 79 +++++++++++++++++ 2 files changed, 158 insertions(+), 6 deletions(-) base-commit: 1508bae37044ebffd7c7e09915f041936f338123 -- 2.40.1

11 months

2
3
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[PATCH net-next v1 10/11] selftests: net: lib: Add several autodefer helpers

by Petr Machata

Add ip_link_set_addr(), ip_link_set_up(), ip_addr_add() and ip_route_add() to the suite of helpers that automatically schedule a corresponding cleanup. When setting a new MAC, one needs to remember the old address first. Move mac_get() from forwarding/ to that end. Signed-off-by: Petr Machata <petrm(a)nvidia.com> Reviewed-by: Ido Schimmel <idosch(a)nvidia.com> --- Notes: CC: Shuah Khan <shuah(a)kernel.org> CC: Benjamin Poirier <bpoirier(a)nvidia.com> CC: Hangbin Liu <liuhangbin(a)gmail.com> CC: Vladimir Oltean <vladimir.oltean(a)nxp.com> CC: linux-kselftest(a)vger.kernel.org tools/testing/selftests/net/forwarding/lib.sh | 7 ---- tools/testing/selftests/net/lib.sh | 39 +++++++++++++++++++ 2 files changed, 39 insertions(+), 7 deletions(-) diff --git a/tools/testing/selftests/net/forwarding/lib.sh b/tools/testing/selftests/net/forwarding/lib.sh index 7337f398f9cc..1fd40bada694 100644 --- a/tools/testing/selftests/net/forwarding/lib.sh +++ b/tools/testing/selftests/net/forwarding/lib.sh @@ -932,13 +932,6 @@ packets_rate() echo $(((t1 - t0) / interval)) } -mac_get() -{ - local if_name=$1 - - ip -j link show dev $if_name | jq -r '.[]["address"]' -} - ether_addr_to_u64() { local addr="$1" diff --git a/tools/testing/selftests/net/lib.sh b/tools/testing/selftests/net/lib.sh index 5ea6537acd2b..2cd5c743b2d9 100644 --- a/tools/testing/selftests/net/lib.sh +++ b/tools/testing/selftests/net/lib.sh @@ -435,6 +435,13 @@ xfail_on_veth() fi } +mac_get() +{ + local if_name=$1 + + ip -j link show dev $if_name | jq -r '.[]["address"]' +} + kill_process() { local pid=$1; shift @@ -459,3 +466,35 @@ ip_link_set_master() ip link set dev "$member" master "$master" defer ip link set dev "$member" nomaster } + +ip_link_set_addr() +{ + local name=$1; shift + local addr=$1; shift + + local old_addr=$(mac_get "$name") + ip link set dev "$name" address "$addr" + defer ip link set dev "$name" address "$old_addr" +} + +ip_link_set_up() +{ + local name=$1; shift + + ip link set dev "$name" up + defer ip link set dev "$name" down +} + +ip_addr_add() +{ + local name=$1; shift + + ip addr add dev "$name" "$@" + defer ip addr del dev "$name" "$@" +} + +ip_route_add() +{ + ip route add "$@" + defer ip route del "$@" +} -- 2.47.0

11 months

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[PATCH net-next v1 09/11] selftests: net: lib: Rename ip_link_master() to ip_link_set_master()

by Petr Machata

Let's have a verb in that function name to make it clearer what's going on. Signed-off-by: Petr Machata <petrm(a)nvidia.com> Reviewed-by: Ido Schimmel <idosch(a)nvidia.com> --- Notes: CC: Shuah Khan <shuah(a)kernel.org> CC: Benjamin Poirier <bpoirier(a)nvidia.com> CC: Hangbin Liu <liuhangbin(a)gmail.com> CC: Vladimir Oltean <vladimir.oltean(a)nxp.com> CC: linux-kselftest(a)vger.kernel.org tools/testing/selftests/net/fdb_notify.sh | 6 +++--- tools/testing/selftests/net/lib.sh | 2 +- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/net/fdb_notify.sh b/tools/testing/selftests/net/fdb_notify.sh index c03151e7791c..c159230c9b62 100755 --- a/tools/testing/selftests/net/fdb_notify.sh +++ b/tools/testing/selftests/net/fdb_notify.sh @@ -49,7 +49,7 @@ test_dup_vxlan_self() { ip_link_add br up type bridge vlan_filtering 1 ip_link_add vx up type vxlan id 2000 dstport 4789 - ip_link_master vx br + ip_link_set_master vx br do_test_dup add "vxlan" dev vx self dst 192.0.2.1 do_test_dup del "vxlan" dev vx self dst 192.0.2.1 @@ -59,7 +59,7 @@ test_dup_vxlan_master() { ip_link_add br up type bridge vlan_filtering 1 ip_link_add vx up type vxlan id 2000 dstport 4789 - ip_link_master vx br + ip_link_set_master vx br do_test_dup add "vxlan master" dev vx master do_test_dup del "vxlan master" dev vx master @@ -79,7 +79,7 @@ test_dup_macvlan_master() ip_link_add br up type bridge vlan_filtering 1 ip_link_add dd up type dummy ip_link_add mv up link dd type macvlan mode passthru - ip_link_master mv br + ip_link_set_master mv br do_test_dup add "macvlan master" dev mv self do_test_dup del "macvlan master" dev mv self diff --git a/tools/testing/selftests/net/lib.sh b/tools/testing/selftests/net/lib.sh index 8994fec1c38f..5ea6537acd2b 100644 --- a/tools/testing/selftests/net/lib.sh +++ b/tools/testing/selftests/net/lib.sh @@ -451,7 +451,7 @@ ip_link_add() defer ip link del dev "$name" } -ip_link_master() +ip_link_set_master() { local member=$1; shift local master=$1; shift -- 2.47.0

11 months

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[net PATCH 1/2] selftests: net: lib: fix broken ping with coreutils ping util

by Christian Marangi

If the coreutils variant of ping is used instead of the busybox one, the ping_do() command is broken. This comes by the fact that for coreutils ping, the ping IP needs to be the very last elements. To handle this, reorder the ping args and make $dip last element. The use of coreutils ping might be useful for case where busybox is not compiled with float interval support and ping command doesn't support 0.1 interval. (in such case a dedicated ping utility is installed instead) Cc: stable(a)vger.kernel.org Fixes: 73bae6736b6b ("selftests: forwarding: Add initial testing framework") Signed-off-by: Christian Marangi <ansuelsmth(a)gmail.com> --- tools/testing/selftests/net/forwarding/lib.sh | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/net/forwarding/lib.sh b/tools/testing/selftests/net/forwarding/lib.sh index c992e385159c..2060f95d5c62 100644 --- a/tools/testing/selftests/net/forwarding/lib.sh +++ b/tools/testing/selftests/net/forwarding/lib.sh @@ -1473,8 +1473,8 @@ ping_do() vrf_name=$(master_name_get $if_name) ip vrf exec $vrf_name \ - $PING $args $dip -c $PING_COUNT -i 0.1 \ - -w $PING_TIMEOUT &> /dev/null + $PING $args -c $PING_COUNT -i 0.1 \ + -w $PING_TIMEOUT $dip &> /dev/null } ping_test() @@ -1504,8 +1504,8 @@ ping6_do() vrf_name=$(master_name_get $if_name) ip vrf exec $vrf_name \ - $PING6 $args $dip -c $PING_COUNT -i 0.1 \ - -w $PING_TIMEOUT &> /dev/null + $PING6 $args -c $PING_COUNT -i 0.1 \ + -w $PING_TIMEOUT $dip &> /dev/null } ping6_test() -- 2.45.2

11 months

2
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[RESEND v3 1/1] selftests/futex: Create test for robust list

by André Almeida

Create a test for the robust list mechanism. Test the following uAPI operations: - Creating a robust mutex where the lock waiter is wake by the kernel when the lock owner died - Setting a robust list to the current task - Getting a robust list from the current task - Getting a robust list from another task - Using the list_op_pending field from robust_list_head struct to test robustness when the lock owner dies before completing the locking - Setting a invalid size for syscall argument `len` Signed-off-by: André Almeida <andrealmeid(a)igalia.com> --- Changes from v2: - Dropped kselftest_harness include, using just futex test API - This is the expected output: TAP version 13 1..6 ok 1 test_robustness ok 2 test_set_robust_list_invalid_size ok 3 test_get_robust_list_self ok 4 test_get_robust_list_child ok 5 test_set_list_op_pending ok 6 test_robust_list_multiple_elements # Totals: pass:6 fail:0 xfail:0 xpass:0 skip:0 error:0 Changes from v1: - Change futex type from int to _Atomic(unsigned int) - Use old futex(FUTEX_WAIT) instead of the new sys_futex_wait() --- .../selftests/futex/functional/.gitignore | 1 + .../selftests/futex/functional/Makefile | 3 +- .../selftests/futex/functional/robust_list.c | 512 ++++++++++++++++++ 3 files changed, 515 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/futex/functional/robust_list.c diff --git a/tools/testing/selftests/futex/functional/.gitignore b/tools/testing/selftests/futex/functional/.gitignore index fbcbdb6963b3..4726e1be7497 100644 --- a/tools/testing/selftests/futex/functional/.gitignore +++ b/tools/testing/selftests/futex/functional/.gitignore @@ -9,3 +9,4 @@ futex_wait_wouldblock futex_wait futex_requeue futex_waitv +robust_list diff --git a/tools/testing/selftests/futex/functional/Makefile b/tools/testing/selftests/futex/functional/Makefile index f79f9bac7918..b8635a1ac7f6 100644 --- a/tools/testing/selftests/futex/functional/Makefile +++ b/tools/testing/selftests/futex/functional/Makefile @@ -17,7 +17,8 @@ TEST_GEN_PROGS := \ futex_wait_private_mapped_file \ futex_wait \ futex_requeue \ - futex_waitv + futex_waitv \ + robust_list TEST_PROGS := run.sh diff --git a/tools/testing/selftests/futex/functional/robust_list.c b/tools/testing/selftests/futex/functional/robust_list.c new file mode 100644 index 000000000000..7bfda2d39821 --- /dev/null +++ b/tools/testing/selftests/futex/functional/robust_list.c @@ -0,0 +1,512 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2024 Igalia S.L. + * + * Robust list test by André Almeida <andrealmeid(a)igalia.com> + * + * The robust list uAPI allows userspace to create "robust" locks, in the sense + * that if the lock holder thread dies, the remaining threads that are waiting + * for the lock won't block forever, waiting for a lock that will never be + * released. + * + * This is achieve by userspace setting a list where a thread can enter all the + * locks (futexes) that it is holding. The robust list is a linked list, and + * userspace register the start of the list with the syscall set_robust_list(). + * If such thread eventually dies, the kernel will walk this list, waking up one + * thread waiting for each futex and marking the futex word with the flag + * FUTEX_OWNER_DIED. + * + * See also + * man set_robust_list + * Documententation/locking/robust-futex-ABI.rst + * Documententation/locking/robust-futexes.rst + */ + +#define _GNU_SOURCE + +#include "futextest.h" +#include "logging.h" + +#include <errno.h> +#include <pthread.h> +#include <signal.h> +#include <stdatomic.h> +#include <stdbool.h> +#include <stddef.h> +#include <sys/mman.h> +#include <sys/wait.h> + +#define STACK_SIZE (1024 * 1024) + +#define FUTEX_TIMEOUT 3 + +static pthread_barrier_t barrier, barrier2; + +int set_robust_list(struct robust_list_head *head, size_t len) +{ + return syscall(SYS_set_robust_list, head, len); +} + +int get_robust_list(int pid, struct robust_list_head **head, size_t *len_ptr) +{ + return syscall(SYS_get_robust_list, pid, head, len_ptr); +} + +/* + * Basic lock struct, contains just the futex word and the robust list element + * Real implementations have also a *prev to easily walk in the list + */ +struct lock_struct { + _Atomic(unsigned int) futex; + struct robust_list list; +}; + +/* + * Helper function to spawn a child thread. Returns -1 on error, pid on success + */ +static int create_child(int (*fn)(void *arg), void *arg) +{ + char *stack; + pid_t pid; + + stack = mmap(NULL, STACK_SIZE, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0); + if (stack == MAP_FAILED) + return -1; + + stack += STACK_SIZE; + + pid = clone(fn, stack, CLONE_VM | SIGCHLD, arg); + + if (pid == -1) + return -1; + + return pid; +} + +/* + * Helper function to prepare and register a robust list + */ +static int set_list(struct robust_list_head *head) +{ + int ret; + + ret = set_robust_list(head, sizeof(struct robust_list_head)); + if (ret) + return ret; + + head->futex_offset = (size_t) offsetof(struct lock_struct, futex) - + (size_t) offsetof(struct lock_struct, list); + head->list.next = &head->list; + head->list_op_pending = NULL; + + return 0; +} + +/* + * A basic (and incomplete) mutex lock function with robustness + */ +static int mutex_lock(struct lock_struct *lock, struct robust_list_head *head, bool error_inject) +{ + _Atomic(unsigned int) *futex = &lock->futex; + int zero = 0, ret = -1; + pid_t tid = gettid(); + + /* + * Set list_op_pending before starting the lock, so the kernel can catch + * the case where the thread died during the lock operation + */ + head->list_op_pending = &lock->list; + + if (atomic_compare_exchange_strong(futex, &zero, tid)) { + /* + * We took the lock, insert it in the robust list + */ + struct robust_list *list = &head->list; + + /* Error injection to test list_op_pending */ + if (error_inject) + return 0; + + while (list->next != &head->list) + list = list->next; + + list->next = &lock->list; + lock->list.next = &head->list; + + ret = 0; + } else { + /* + * We didn't take the lock, wait until the owner wakes (or dies) + */ + struct timespec to; + + clock_gettime(CLOCK_MONOTONIC, &to); + to.tv_sec = to.tv_sec + FUTEX_TIMEOUT; + + tid = atomic_load(futex); + /* Kernel ignores futexes without the waiters flag */ + tid |= FUTEX_WAITERS; + atomic_store(futex, tid); + + ret = futex_wait((futex_t *) futex, tid, &to, 0); + + /* + * A real mutex_lock() implementation would loop here to finally + * take the lock. We don't care about that, so we stop here. + */ + } + + head->list_op_pending = NULL; + + return ret; +} + +/* + * This child thread will succeed taking the lock, and then will exit holding it + */ +static int child_fn_lock(void *arg) +{ + struct lock_struct *lock = (struct lock_struct *) arg; + struct robust_list_head head; + int ret; + + ret = set_list(&head); + if (ret) + ksft_test_result_fail("set_robust_list error\n"); + + ret = mutex_lock(lock, &head, false); + if (ret) + ksft_test_result_fail("mutex_lock error\n"); + + pthread_barrier_wait(&barrier); + + /* + * There's a race here: the parent thread needs to be inside + * futex_wait() before the child thread dies, otherwise it will miss the + * wakeup from handle_futex_death() that this child will emit. We wait a + * little bit just to make sure that this happens. + */ + sleep(1); + + return 0; +} + +/* + * Spawns a child thread that will set a robust list, take the lock, register it + * in the robust list and die. The parent thread will wait on this futex, and + * should be waken up when the child exits. + */ +static void test_robustness() +{ + struct lock_struct lock = { .futex = 0 }; + struct robust_list_head head; + _Atomic(unsigned int) *futex = &lock.futex; + int ret; + + ret = set_list(&head); + ASSERT_EQ(ret, 0); + + /* + * Lets use a barrier to ensure that the child thread takes the lock + * before the parent + */ + ret = pthread_barrier_init(&barrier, NULL, 2); + ASSERT_EQ(ret, 0); + + ret = create_child(&child_fn_lock, &lock); + ASSERT_NE(ret, -1); + + pthread_barrier_wait(&barrier); + ret = mutex_lock(&lock, &head, false); + + /* + * futex_wait() should return 0 and the futex word should be marked with + * FUTEX_OWNER_DIED + */ + ASSERT_EQ(ret, 0); + if (ret != 0) + printf("futex wait returned %d", errno); + + ASSERT_TRUE(*futex | FUTEX_OWNER_DIED); + + pthread_barrier_destroy(&barrier); + + ksft_test_result_pass("%s\n", __func__); +} + +/* + * The only valid value for len is sizeof(*head) + */ +static void test_set_robust_list_invalid_size() +{ + struct robust_list_head head; + size_t head_size = sizeof(struct robust_list_head); + int ret; + + ret = set_robust_list(&head, head_size); + ASSERT_EQ(ret, 0); + + ret = set_robust_list(&head, head_size * 2); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, EINVAL); + + ret = set_robust_list(&head, head_size - 1); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, EINVAL); + + ret = set_robust_list(&head, 0); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, EINVAL); + + ksft_test_result_pass("%s\n", __func__); +} + +/* + * Test get_robust_list with pid = 0, getting the list of the running thread + */ +static void test_get_robust_list_self() +{ + struct robust_list_head head, head2, *get_head; + size_t head_size = sizeof(struct robust_list_head), len_ptr; + int ret; + + ret = set_robust_list(&head, head_size); + ASSERT_EQ(ret, 0); + + ret = get_robust_list(0, &get_head, &len_ptr); + ASSERT_EQ(ret, 0); + ASSERT_EQ(get_head, &head); + ASSERT_EQ(head_size, len_ptr); + + ret = set_robust_list(&head2, head_size); + ASSERT_EQ(ret, 0); + + ret = get_robust_list(0, &get_head, &len_ptr); + ASSERT_EQ(ret, 0); + ASSERT_EQ(get_head, &head2); + ASSERT_EQ(head_size, len_ptr); + + ksft_test_result_pass("%s\n", __func__); +} + +static int child_list(void *arg) +{ + struct robust_list_head *head = (struct robust_list_head *) arg; + int ret; + + ret = set_robust_list(head, sizeof(struct robust_list_head)); + if (ret) + ksft_test_result_fail("set_robust_list error\n"); + + pthread_barrier_wait(&barrier); + pthread_barrier_wait(&barrier2); + + return 0; +} + +/* + * Test get_robust_list from another thread. We use two barriers here to ensure + * that: + * 1) the child thread set the list before we try to get it from the + * parent + * 2) the child thread still alive when we try to get the list from it + */ +static void test_get_robust_list_child() +{ + pid_t tid; + int ret; + struct robust_list_head head, *get_head; + size_t len_ptr; + + ret = pthread_barrier_init(&barrier, NULL, 2); + ret = pthread_barrier_init(&barrier2, NULL, 2); + ASSERT_EQ(ret, 0); + + tid = create_child(&child_list, &head); + ASSERT_NE(tid, -1); + + pthread_barrier_wait(&barrier); + + ret = get_robust_list(tid, &get_head, &len_ptr); + ASSERT_EQ(ret, 0); + ASSERT_EQ(&head, get_head); + + pthread_barrier_wait(&barrier2); + + pthread_barrier_destroy(&barrier); + pthread_barrier_destroy(&barrier2); + + ksft_test_result_pass("%s\n", __func__); +} + +static int child_fn_lock_with_error(void *arg) +{ + struct lock_struct *lock = (struct lock_struct *) arg; + struct robust_list_head head; + int ret; + + ret = set_list(&head); + if (ret) + ksft_test_result_fail("set_robust_list error\n"); + + ret = mutex_lock(lock, &head, true); + if (ret) + ksft_test_result_fail("mutex_lock error\n"); + + pthread_barrier_wait(&barrier); + + sleep(1); + + return 0; +} + +/* + * Same as robustness test, but inject an error where the mutex_lock() exits + * earlier, just after setting list_op_pending and taking the lock, to test the + * list_op_pending mechanism + */ +static void test_set_list_op_pending() +{ + struct lock_struct lock = { .futex = 0 }; + struct robust_list_head head; + _Atomic(unsigned int) *futex = &lock.futex; + int ret; + + ret = set_list(&head); + ASSERT_EQ(ret, 0); + + ret = pthread_barrier_init(&barrier, NULL, 2); + ASSERT_EQ(ret, 0); + + ret = create_child(&child_fn_lock_with_error, &lock); + ASSERT_NE(ret, -1); + + pthread_barrier_wait(&barrier); + ret = mutex_lock(&lock, &head, false); + + ASSERT_EQ(ret, 0); + if (ret != 0) + printf("futex wait returned %d", errno); + + ASSERT_TRUE(*futex | FUTEX_OWNER_DIED); + + pthread_barrier_destroy(&barrier); + + ksft_test_result_pass("%s\n", __func__); +} + +#define CHILD_NR 10 + +static int child_lock_holder(void *arg) +{ + struct lock_struct *locks = (struct lock_struct *) arg; + struct robust_list_head head; + int i; + + set_list(&head); + + for (i = 0; i < CHILD_NR; i++) { + locks[i].futex = 0; + mutex_lock(&locks[i], &head, false); + } + + pthread_barrier_wait(&barrier); + pthread_barrier_wait(&barrier2); + + sleep(1); + return 0; +} + +static int child_wait_lock(void *arg) +{ + struct lock_struct *lock = (struct lock_struct *) arg; + struct robust_list_head head; + int ret; + + pthread_barrier_wait(&barrier2); + ret = mutex_lock(lock, &head, false); + + if (ret) + ksft_test_result_fail("mutex_lock error\n"); + + if (!(lock->futex | FUTEX_OWNER_DIED)) + ksft_test_result_fail("futex not marked with FUTEX_OWNER_DIED\n"); + + return 0; +} + +/* + * Test a robust list of more than one element. All the waiters should wake when + * the holder dies + */ +static void test_robust_list_multiple_elements() +{ + struct lock_struct locks[CHILD_NR]; + int i, ret; + + ret = pthread_barrier_init(&barrier, NULL, 2); + ASSERT_EQ(ret, 0); + ret = pthread_barrier_init(&barrier2, NULL, CHILD_NR + 1); + ASSERT_EQ(ret, 0); + + create_child(&child_lock_holder, &locks); + + /* Wait until the locker thread takes the look */ + pthread_barrier_wait(&barrier); + + for (i = 0; i < CHILD_NR; i++) + create_child(&child_wait_lock, &locks[i]); + + /* Wait for all children to return */ + while (wait(NULL) > 0); + + pthread_barrier_destroy(&barrier); + pthread_barrier_destroy(&barrier2); + + ksft_test_result_pass("%s\n", __func__); +} + +void usage(char *prog) +{ + printf("Usage: %s\n", prog); + printf(" -c Use color\n"); + printf(" -h Display this help message\n"); + printf(" -v L Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n", + VQUIET, VCRITICAL, VINFO); +} + +int main(int argc, char *argv[]) +{ + int c; + + while ((c = getopt(argc, argv, "cht:v:")) != -1) { + switch (c) { + case 'c': + log_color(1); + break; + case 'h': + usage(basename(argv[0])); + exit(0); + case 'v': + log_verbosity(atoi(optarg)); + break; + default: + usage(basename(argv[0])); + exit(1); + } + } + + ksft_print_header(); + ksft_set_plan(6); + + test_robustness(); + test_set_robust_list_invalid_size(); + test_get_robust_list_self(); + test_get_robust_list_child(); + test_set_list_op_pending(); + test_robust_list_multiple_elements(); + + ksft_print_cnts(); + return 0; +} -- 2.47.1

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Linux-kselftest-mirror December 2024