[SRU][Focal][PATCH] Revert "bpf: Zero-fill re-used per-cpu map element"
Kamal Mostafa
kamal at canonical.com
Fri Dec 4 18:47:57 UTC 2020
BugLink: https://bugs.launchpad.net/bugs/1906866
This reverts commit d946d4ddd6af531398201e7ce8f73bd1d8a98e2a.
Reported upstream:
https://lore.kernel.org/stable/20201204182846.27110-1-kamal@canonical.com/T/#u
This v5.4.78 commit breaks the tools/testing/selftests/bpf build:
[linux-5.4.y] c602ad2b52dc bpf: Zero-fill re-used per-cpu map element
[focal] d946d4ddd6af bpf: Zero-fill re-used per-cpu map element
Like this:
prog_tests/map_init.c:5:10: fatal error: test_map_init.skel.h:
No such file or directory
5 | #include "test_map_init.skel.h"
Because tools/testing/selftests/bpf/Makefile in v5.4 does not have the
"skeleton header generation" stuff (circa v5.6).
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
kernel/bpf/hashtab.c | 30 +--
.../selftests/bpf/prog_tests/map_init.c | 214 ------------------
.../selftests/bpf/progs/test_map_init.c | 33 ---
3 files changed, 2 insertions(+), 275 deletions(-)
delete mode 100644 tools/testing/selftests/bpf/prog_tests/map_init.c
delete mode 100644 tools/testing/selftests/bpf/progs/test_map_init.c
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 03a67583f6fb..728ffec52cf3 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -709,32 +709,6 @@ static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr,
}
}
-static void pcpu_init_value(struct bpf_htab *htab, void __percpu *pptr,
- void *value, bool onallcpus)
-{
- /* When using prealloc and not setting the initial value on all cpus,
- * zero-fill element values for other cpus (just as what happens when
- * not using prealloc). Otherwise, bpf program has no way to ensure
- * known initial values for cpus other than current one
- * (onallcpus=false always when coming from bpf prog).
- */
- if (htab_is_prealloc(htab) && !onallcpus) {
- u32 size = round_up(htab->map.value_size, 8);
- int current_cpu = raw_smp_processor_id();
- int cpu;
-
- for_each_possible_cpu(cpu) {
- if (cpu == current_cpu)
- bpf_long_memcpy(per_cpu_ptr(pptr, cpu), value,
- size);
- else
- memset(per_cpu_ptr(pptr, cpu), 0, size);
- }
- } else {
- pcpu_copy_value(htab, pptr, value, onallcpus);
- }
-}
-
static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab)
{
return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS &&
@@ -805,7 +779,7 @@ static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
}
}
- pcpu_init_value(htab, pptr, value, onallcpus);
+ pcpu_copy_value(htab, pptr, value, onallcpus);
if (!prealloc)
htab_elem_set_ptr(l_new, key_size, pptr);
@@ -1101,7 +1075,7 @@ static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
value, onallcpus);
} else {
- pcpu_init_value(htab, htab_elem_get_ptr(l_new, key_size),
+ pcpu_copy_value(htab, htab_elem_get_ptr(l_new, key_size),
value, onallcpus);
hlist_nulls_add_head_rcu(&l_new->hash_node, head);
l_new = NULL;
diff --git a/tools/testing/selftests/bpf/prog_tests/map_init.c b/tools/testing/selftests/bpf/prog_tests/map_init.c
deleted file mode 100644
index 14a31109dd0e..000000000000
--- a/tools/testing/selftests/bpf/prog_tests/map_init.c
+++ /dev/null
@@ -1,214 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/* Copyright (c) 2020 Tessares SA <http://www.tessares.net> */
-
-#include <test_progs.h>
-#include "test_map_init.skel.h"
-
-#define TEST_VALUE 0x1234
-#define FILL_VALUE 0xdeadbeef
-
-static int nr_cpus;
-static int duration;
-
-typedef unsigned long long map_key_t;
-typedef unsigned long long map_value_t;
-typedef struct {
- map_value_t v; /* padding */
-} __bpf_percpu_val_align pcpu_map_value_t;
-
-
-static int map_populate(int map_fd, int num)
-{
- pcpu_map_value_t value[nr_cpus];
- int i, err;
- map_key_t key;
-
- for (i = 0; i < nr_cpus; i++)
- bpf_percpu(value, i) = FILL_VALUE;
-
- for (key = 1; key <= num; key++) {
- err = bpf_map_update_elem(map_fd, &key, value, BPF_NOEXIST);
- if (!ASSERT_OK(err, "bpf_map_update_elem"))
- return -1;
- }
-
- return 0;
-}
-
-static struct test_map_init *setup(enum bpf_map_type map_type, int map_sz,
- int *map_fd, int populate)
-{
- struct test_map_init *skel;
- int err;
-
- skel = test_map_init__open();
- if (!ASSERT_OK_PTR(skel, "skel_open"))
- return NULL;
-
- err = bpf_map__set_type(skel->maps.hashmap1, map_type);
- if (!ASSERT_OK(err, "bpf_map__set_type"))
- goto error;
-
- err = bpf_map__set_max_entries(skel->maps.hashmap1, map_sz);
- if (!ASSERT_OK(err, "bpf_map__set_max_entries"))
- goto error;
-
- err = test_map_init__load(skel);
- if (!ASSERT_OK(err, "skel_load"))
- goto error;
-
- *map_fd = bpf_map__fd(skel->maps.hashmap1);
- if (CHECK(*map_fd < 0, "bpf_map__fd", "failed\n"))
- goto error;
-
- err = map_populate(*map_fd, populate);
- if (!ASSERT_OK(err, "map_populate"))
- goto error_map;
-
- return skel;
-
-error_map:
- close(*map_fd);
-error:
- test_map_init__destroy(skel);
- return NULL;
-}
-
-/* executes bpf program that updates map with key, value */
-static int prog_run_insert_elem(struct test_map_init *skel, map_key_t key,
- map_value_t value)
-{
- struct test_map_init__bss *bss;
-
- bss = skel->bss;
-
- bss->inKey = key;
- bss->inValue = value;
- bss->inPid = getpid();
-
- if (!ASSERT_OK(test_map_init__attach(skel), "skel_attach"))
- return -1;
-
- /* Let tracepoint trigger */
- syscall(__NR_getpgid);
-
- test_map_init__detach(skel);
-
- return 0;
-}
-
-static int check_values_one_cpu(pcpu_map_value_t *value, map_value_t expected)
-{
- int i, nzCnt = 0;
- map_value_t val;
-
- for (i = 0; i < nr_cpus; i++) {
- val = bpf_percpu(value, i);
- if (val) {
- if (CHECK(val != expected, "map value",
- "unexpected for cpu %d: 0x%llx\n", i, val))
- return -1;
- nzCnt++;
- }
- }
-
- if (CHECK(nzCnt != 1, "map value", "set for %d CPUs instead of 1!\n",
- nzCnt))
- return -1;
-
- return 0;
-}
-
-/* Add key=1 elem with values set for all CPUs
- * Delete elem key=1
- * Run bpf prog that inserts new key=1 elem with value=0x1234
- * (bpf prog can only set value for current CPU)
- * Lookup Key=1 and check value is as expected for all CPUs:
- * value set by bpf prog for one CPU, 0 for all others
- */
-static void test_pcpu_map_init(void)
-{
- pcpu_map_value_t value[nr_cpus];
- struct test_map_init *skel;
- int map_fd, err;
- map_key_t key;
-
- /* max 1 elem in map so insertion is forced to reuse freed entry */
- skel = setup(BPF_MAP_TYPE_PERCPU_HASH, 1, &map_fd, 1);
- if (!ASSERT_OK_PTR(skel, "prog_setup"))
- return;
-
- /* delete element so the entry can be re-used*/
- key = 1;
- err = bpf_map_delete_elem(map_fd, &key);
- if (!ASSERT_OK(err, "bpf_map_delete_elem"))
- goto cleanup;
-
- /* run bpf prog that inserts new elem, re-using the slot just freed */
- err = prog_run_insert_elem(skel, key, TEST_VALUE);
- if (!ASSERT_OK(err, "prog_run_insert_elem"))
- goto cleanup;
-
- /* check that key=1 was re-created by bpf prog */
- err = bpf_map_lookup_elem(map_fd, &key, value);
- if (!ASSERT_OK(err, "bpf_map_lookup_elem"))
- goto cleanup;
-
- /* and has expected values */
- check_values_one_cpu(value, TEST_VALUE);
-
-cleanup:
- test_map_init__destroy(skel);
-}
-
-/* Add key=1 and key=2 elems with values set for all CPUs
- * Run bpf prog that inserts new key=3 elem
- * (only for current cpu; other cpus should have initial value = 0)
- * Lookup Key=1 and check value is as expected for all CPUs
- */
-static void test_pcpu_lru_map_init(void)
-{
- pcpu_map_value_t value[nr_cpus];
- struct test_map_init *skel;
- int map_fd, err;
- map_key_t key;
-
- /* Set up LRU map with 2 elements, values filled for all CPUs.
- * With these 2 elements, the LRU map is full
- */
- skel = setup(BPF_MAP_TYPE_LRU_PERCPU_HASH, 2, &map_fd, 2);
- if (!ASSERT_OK_PTR(skel, "prog_setup"))
- return;
-
- /* run bpf prog that inserts new key=3 element, re-using LRU slot */
- key = 3;
- err = prog_run_insert_elem(skel, key, TEST_VALUE);
- if (!ASSERT_OK(err, "prog_run_insert_elem"))
- goto cleanup;
-
- /* check that key=3 replaced one of earlier elements */
- err = bpf_map_lookup_elem(map_fd, &key, value);
- if (!ASSERT_OK(err, "bpf_map_lookup_elem"))
- goto cleanup;
-
- /* and has expected values */
- check_values_one_cpu(value, TEST_VALUE);
-
-cleanup:
- test_map_init__destroy(skel);
-}
-
-void test_map_init(void)
-{
- nr_cpus = bpf_num_possible_cpus();
- if (nr_cpus <= 1) {
- printf("%s:SKIP: >1 cpu needed for this test\n", __func__);
- test__skip();
- return;
- }
-
- if (test__start_subtest("pcpu_map_init"))
- test_pcpu_map_init();
- if (test__start_subtest("pcpu_lru_map_init"))
- test_pcpu_lru_map_init();
-}
diff --git a/tools/testing/selftests/bpf/progs/test_map_init.c b/tools/testing/selftests/bpf/progs/test_map_init.c
deleted file mode 100644
index c89d28ead673..000000000000
--- a/tools/testing/selftests/bpf/progs/test_map_init.c
+++ /dev/null
@@ -1,33 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/* Copyright (c) 2020 Tessares SA <http://www.tessares.net> */
-
-#include "vmlinux.h"
-#include <bpf/bpf_helpers.h>
-
-__u64 inKey = 0;
-__u64 inValue = 0;
-__u32 inPid = 0;
-
-struct {
- __uint(type, BPF_MAP_TYPE_PERCPU_HASH);
- __uint(max_entries, 2);
- __type(key, __u64);
- __type(value, __u64);
-} hashmap1 SEC(".maps");
-
-
-SEC("tp/syscalls/sys_enter_getpgid")
-int sysenter_getpgid(const void *ctx)
-{
- /* Just do it for once, when called from our own test prog. This
- * ensures the map value is only updated for a single CPU.
- */
- int cur_pid = bpf_get_current_pid_tgid() >> 32;
-
- if (cur_pid == inPid)
- bpf_map_update_elem(&hashmap1, &inKey, &inValue, BPF_NOEXIST);
-
- return 0;
-}
-
-char _license[] SEC("license") = "GPL";
--
2.17.1
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