Add various tests to check maximum number of supported programs
being attached:

  # ./vmtest.sh -- ./test_progs -t tc_opts
  [...]
  ./test_progs -t tc_opts
  [    1.185325] bpf_testmod: loading out-of-tree module taints kernel.
  [    1.186826] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel
  [    1.270123] tsc: Refined TSC clocksource calibration: 3407.988 MHz
  [    1.272428] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x311fc932722, max_idle_ns: 440795381586 ns
  [    1.276408] clocksource: Switched to clocksource tsc
  #252     tc_opts_after:OK
  #253     tc_opts_append:OK
  #254     tc_opts_basic:OK
  #255     tc_opts_before:OK
  #256     tc_opts_chain_classic:OK
  #257     tc_opts_chain_mixed:OK
  #258     tc_opts_delete_empty:OK
  #259     tc_opts_demixed:OK
  #260     tc_opts_detach:OK
  #261     tc_opts_detach_after:OK
  #262     tc_opts_detach_before:OK
  #263     tc_opts_dev_cleanup:OK
  #264     tc_opts_invalid:OK
  #265     tc_opts_max:OK              <--- (new test)
  #266     tc_opts_mixed:OK
  #267     tc_opts_prepend:OK
  #268     tc_opts_replace:OK
  #269     tc_opts_revision:OK
  Summary: 18/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Add various tests to check maximum number of supported programs
being attached:

  # ./vmtest.sh -- ./test_progs -t tc_opts
  [...]
  ./test_progs -t tc_opts
  [    1.185325] bpf_testmod: loading out-of-tree module taints kernel.
  [    1.186826] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel
  [    1.270123] tsc: Refined TSC clocksource calibration: 3407.988 MHz
  [    1.272428] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x311fc932722, max_idle_ns: 440795381586 ns
  [    1.276408] clocksource: Switched to clocksource tsc
  #252     tc_opts_after:OK
  #253     tc_opts_append:OK
  #254     tc_opts_basic:OK
  #255     tc_opts_before:OK
  #256     tc_opts_chain_classic:OK
  #257     tc_opts_chain_mixed:OK
  #258     tc_opts_delete_empty:OK
  #259     tc_opts_demixed:OK
  #260     tc_opts_detach:OK
  #261     tc_opts_detach_after:OK
  #262     tc_opts_detach_before:OK
  #263     tc_opts_dev_cleanup:OK
  #264     tc_opts_invalid:OK
  #265     tc_opts_max:OK              <--- (new test)
  #266     tc_opts_mixed:OK
  #267     tc_opts_prepend:OK
  #268     tc_opts_replace:OK
  #269     tc_opts_revision:OK
  Summary: 18/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230929204121.20305-2-daniel@iogearbox.net

Add various tests to check maximum number of supported programs
being attached:

  # ./vmtest.sh -- ./test_progs -t tc_opts
  [...]
  ./test_progs -t tc_opts
  [    1.185325] bpf_testmod: loading out-of-tree module taints kernel.
  [    1.186826] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel
  [    1.270123] tsc: Refined TSC clocksource calibration: 3407.988 MHz
  [    1.272428] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x311fc932722, max_idle_ns: 440795381586 ns
  [    1.276408] clocksource: Switched to clocksource tsc
  #252     tc_opts_after:OK
  #253     tc_opts_append:OK
  #254     tc_opts_basic:OK
  #255     tc_opts_before:OK
  #256     tc_opts_chain_classic:OK
  #257     tc_opts_chain_mixed:OK
  #258     tc_opts_delete_empty:OK
  #259     tc_opts_demixed:OK
  #260     tc_opts_detach:OK
  #261     tc_opts_detach_after:OK
  #262     tc_opts_detach_before:OK
  #263     tc_opts_dev_cleanup:OK
  #264     tc_opts_invalid:OK
  #265     tc_opts_max:OK              <--- (new test)
  #266     tc_opts_mixed:OK
  #267     tc_opts_prepend:OK
  #268     tc_opts_replace:OK
  #269     tc_opts_revision:OK
  Summary: 18/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230929204121.20305-2-daniel@iogearbox.net

Add a new test case which performs double query of the bpf_mprog through
libbpf API, but also via raw bpf(2) syscall. This is testing to gather
first the count and then in a subsequent probe the full information with
the program array without clearing passed structs in between.

  # ./vmtest.sh -- ./test_progs -t tc_opts
  [...]
  ./test_progs -t tc_opts
  [    1.398818] tsc: Refined TSC clocksource calibration: 3407.999 MHz
  [    1.400263] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x311fd336761, max_idle_ns: 440795243819 ns
  [    1.402734] clocksource: Switched to clocksource tsc
  [    1.426639] bpf_testmod: loading out-of-tree module taints kernel.
  [    1.428112] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel
  #252     tc_opts_after:OK
  #253     tc_opts_append:OK
  #254     tc_opts_basic:OK
  #255     tc_opts_before:OK
  #256     tc_opts_chain_classic:OK
  #257     tc_opts_chain_mixed:OK
  #258     tc_opts_delete_empty:OK
  #259     tc_opts_demixed:OK
  #260     tc_opts_detach:OK
  #261     tc_opts_detach_after:OK
  #262     tc_opts_detach_before:OK
  #263     tc_opts_dev_cleanup:OK
  #264     tc_opts_invalid:OK
  #265     tc_opts_max:OK
  #266     tc_opts_mixed:OK
  #267     tc_opts_prepend:OK
  #268     tc_opts_query:OK            <--- (new test)
  #269     tc_opts_replace:OK
  #270     tc_opts_revision:OK
  Summary: 19/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Add a new test case to query on an empty bpf_mprog and pass the revision
directly into expected_revision for attachment to assert that this does
succeed.

  ./test_progs -t tc_opts
  [    1.406778] tsc: Refined TSC clocksource calibration: 3407.990 MHz
  [    1.408863] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x311fcaf6eb0, max_idle_ns: 440795321766 ns
  [    1.412419] clocksource: Switched to clocksource tsc
  [    1.428671] bpf_testmod: loading out-of-tree module taints kernel.
  [    1.430260] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel
  #252     tc_opts_after:OK
  #253     tc_opts_append:OK
  #254     tc_opts_basic:OK
  #255     tc_opts_before:OK
  #256     tc_opts_chain_classic:OK
  #257     tc_opts_chain_mixed:OK
  #258     tc_opts_delete_empty:OK
  #259     tc_opts_demixed:OK
  #260     tc_opts_detach:OK
  #261     tc_opts_detach_after:OK
  #262     tc_opts_detach_before:OK
  #263     tc_opts_dev_cleanup:OK
  #264     tc_opts_invalid:OK
  #265     tc_opts_max:OK
  #266     tc_opts_mixed:OK
  #267     tc_opts_prepend:OK
  #268     tc_opts_query:OK
  #269     tc_opts_query_attach:OK     <--- (new test)
  #270     tc_opts_replace:OK
  #271     tc_opts_revision:OK
  Summary: 20/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Add a new test case which performs double query of the bpf_mprog through
libbpf API, but also via raw bpf(2) syscall. This is testing to gather
first the count and then in a subsequent probe the full information with
the program array without clearing passed structs in between.

  # ./vmtest.sh -- ./test_progs -t tc_opts
  [...]
  ./test_progs -t tc_opts
  [    1.398818] tsc: Refined TSC clocksource calibration: 3407.999 MHz
  [    1.400263] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x311fd336761, max_idle_ns: 440795243819 ns
  [    1.402734] clocksource: Switched to clocksource tsc
  [    1.426639] bpf_testmod: loading out-of-tree module taints kernel.
  [    1.428112] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel
  #252     tc_opts_after:OK
  #253     tc_opts_append:OK
  #254     tc_opts_basic:OK
  #255     tc_opts_before:OK
  #256     tc_opts_chain_classic:OK
  #257     tc_opts_chain_mixed:OK
  #258     tc_opts_delete_empty:OK
  #259     tc_opts_demixed:OK
  #260     tc_opts_detach:OK
  #261     tc_opts_detach_after:OK
  #262     tc_opts_detach_before:OK
  #263     tc_opts_dev_cleanup:OK
  #264     tc_opts_invalid:OK
  #265     tc_opts_max:OK
  #266     tc_opts_mixed:OK
  #267     tc_opts_prepend:OK
  #268     tc_opts_query:OK            <--- (new test)
  #269     tc_opts_replace:OK
  #270     tc_opts_revision:OK
  Summary: 19/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20231006220655.1653-4-daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

Add several new test cases which assert corner cases on the mprog query
mechanism, for example, around passing in a too small or a larger array
than the current count.

  ./test_progs -t tc_opts
  #252     tc_opts_after:OK
  #253     tc_opts_append:OK
  #254     tc_opts_basic:OK
  #255     tc_opts_before:OK
  #256     tc_opts_chain_classic:OK
  #257     tc_opts_chain_mixed:OK
  #258     tc_opts_delete_empty:OK
  #259     tc_opts_demixed:OK
  #260     tc_opts_detach:OK
  #261     tc_opts_detach_after:OK
  #262     tc_opts_detach_before:OK
  #263     tc_opts_dev_cleanup:OK
  #264     tc_opts_invalid:OK
  #265     tc_opts_max:OK
  #266     tc_opts_mixed:OK
  #267     tc_opts_prepend:OK
  #268     tc_opts_query:OK
  #269     tc_opts_query_attach:OK
  #270     tc_opts_replace:OK
  #271     tc_opts_revision:OK
  Summary: 20/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/20231017081728.24769-1-daniel@iogearbox.net

The CI could fail with

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 kernel-patches#264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:PASS:bpf_map_update_batch -ERANGE 0 nsec
 test_percpu_map_op_cpu_flag:PASS:bpf_map_update_batch all_cpus 0 nsec
 test_percpu_map_op_cpu_flag:PASS:bpf_map_update_batch specified cpu 0 nsec
 test_percpu_map_op_cpu_flag:PASS:bpf_map_lookup_batch specified cpu 0 nsec
 test_percpu_map_op_cpu_flag:PASS:bpf_map_lookup_batch value on specified cpu 0 nsec
 test_percpu_map_op_cpu_flag:PASS:bpf_map_lookup_batch value on specified cpu 0 nsec
 test_percpu_map_op_cpu_flag:PASS:bpf_map_lookup_batch value on specified cpu 0 nsec
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The reason of unexpected value on CPU kernel-patches#3 was no value found for key 3.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

The CI could fail with

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 kernel-patches#264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:PASS:bpf_map_update_batch -ERANGE 0 nsec
 test_percpu_map_op_cpu_flag:PASS:bpf_map_update_batch all_cpus 0 nsec
 test_percpu_map_op_cpu_flag:PASS:bpf_map_update_batch specified cpu 0 nsec
 test_percpu_map_op_cpu_flag:PASS:bpf_map_lookup_batch specified cpu 0 nsec
 test_percpu_map_op_cpu_flag:PASS:bpf_map_lookup_batch value on specified cpu 0 nsec
 test_percpu_map_op_cpu_flag:PASS:bpf_map_lookup_batch value on specified cpu 0 nsec
 test_percpu_map_op_cpu_flag:PASS:bpf_map_lookup_batch value on specified cpu 0 nsec
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The reason of unexpected value on CPU kernel-patches#3 was no value found for key 3, or
was not updated by 'update_batch()'.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

The CI could fail with

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 kernel-patches#264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:PASS:bpf_map_update_batch -ERANGE 0 nsec
 test_percpu_map_op_cpu_flag:PASS:bpf_map_update_batch all_cpus 0 nsec
 test_percpu_map_op_cpu_flag:PASS:bpf_map_update_batch specified cpu 0 nsec
 test_percpu_map_op_cpu_flag:PASS:bpf_map_lookup_batch specified cpu 0 nsec
 test_percpu_map_op_cpu_flag:PASS:bpf_map_lookup_batch value on specified cpu 0 nsec
 test_percpu_map_op_cpu_flag:PASS:bpf_map_lookup_batch value on specified cpu 0 nsec
 test_percpu_map_op_cpu_flag:PASS:bpf_map_lookup_batch value on specified cpu 0 nsec
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The reason of unexpected value was that an elem was deleted occasionarily.

However, in the test, there is no 'delete_elem()'.

The only chance to delete elem is LRU eviction.

If the extra node was not found when updating elem, an eviction would be
triggered regardless.

To avoid such occasionary eviction, preserve abundant elems by setting
max_entries to 'nr_cpus * 2', and using the first nr_cpus elems.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 kernel-patches#264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() may trigger eviction if the extra element is not available
on the current CPU’s local freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 kernel-patches#264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 kernel-patches#264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

CI occasionally reports failures in the
percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example:

 First test_progs failure (test_progs_no_alu32-x86_64-llvm-21):
 #264/15 percpu_alloc/cpu_flag_lru_percpu_hash
 ...
 test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054

The unexpected value indicates that an element was removed from the map.
However, the test never calls delete_elem(), so the only possible cause
is LRU eviction.

This can happen when the current task migrates to another CPU: an
update_elem() triggers eviction because there is no available LRU node
on local freelist and global freelist.

Harden the test against this behavior by provisioning sufficient spare
elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using
the first nr_cpus entries, ensuring that updates do not spuriously trigger
LRU eviction.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20260119133417.19739-1-leon.hwang@linux.dev