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selftests/bpf: Factor out arena stream tests to own source
Prior commit [0] added arena tests to the existing streams tests. As kernel arena code is not always compiled (only 64-bit), building streams tests in test_progs fails for 32-bit systems: progs/stream.c:136:21: error: incomplete definition of type 'struct bpf_arena' 136 | user_vm_start = ptr->user_vm_start; | ~~~^ .../include/vmlinux.h:34574:8: note: forward declaration of 'struct bpf_arena' 34574 | struct bpf_arena; | ^ progs/stream.c:170:21: error: incomplete definition of type 'struct bpf_arena' 170 | user_vm_start = ptr->user_vm_start; | ~~~^ .../include/vmlinux.h:34574:8: note: forward declaration of 'struct bpf_arena' 34574 | struct bpf_arena; | ^ 2 errors generated. Previous arena test code was mainly added as separate source files [1], allowing either their temporary removal as a workaround or, ultimately, exclusion via Makefile to build successfully. Follow the prior approach by separating out arena-specific stream test sources. 0: 86f2225 ("selftests/bpf: Add tests for arena fault reporting") 1: arena_spin_lock.c, arena_atomics.c, arena_htab.c, arena_htab_asm.c, arena_list.c, verifier_arena.c, verifier_arena_large.c Signed-off-by: Tony Ambardar <[email protected]>
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+206
-189
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4 files changed

+206
-189
lines changed

‎tools/testing/selftests/bpf/prog_tests/arena_stream.c‎

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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
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#include <test_progs.h>
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#include <sys/mman.h>
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#include "arena_stream.skel.h"
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static void test_address(struct bpf_program *prog, unsigned long *fault_addr_p)
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{
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LIBBPF_OPTS(bpf_test_run_opts, opts);
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LIBBPF_OPTS(bpf_prog_stream_read_opts, ropts);
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int ret, prog_fd;
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char fault_addr[64];
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char buf[1024];
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prog_fd = bpf_program__fd(prog);
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ret = bpf_prog_test_run_opts(prog_fd, &opts);
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ASSERT_OK(ret, "ret");
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ASSERT_OK(opts.retval, "retval");
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sprintf(fault_addr, "0x%lx", *fault_addr_p);
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ret = bpf_prog_stream_read(prog_fd, BPF_STREAM_STDERR, buf, sizeof(buf), &ropts);
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ASSERT_GT(ret, 0, "stream read");
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ASSERT_LE(ret, 1023, "len for buf");
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buf[ret] = '\0';
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if (!ASSERT_HAS_SUBSTR(buf, fault_addr, "fault_addr")) {
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fprintf(stderr, "Output from stream:\n%s\n", buf);
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fprintf(stderr, "Fault Addr: %s\n", fault_addr);
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}
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}
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void test_stream_arena_fault_address(void)
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{
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struct arena_stream *skel;
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#if !defined(__x86_64__) && !defined(__aarch64__)
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printf("%s:SKIP: arena fault reporting not supported\n", __func__);
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test__skip();
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return;
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#endif
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skel = arena_stream__open_and_load();
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if (!ASSERT_OK_PTR(skel, "arena_stream__open_and_load"))
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return;
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if (test__start_subtest("read_fault"))
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test_address(skel->progs.stream_arena_read_fault, &skel->bss->fault_addr);
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if (test__start_subtest("write_fault"))
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test_address(skel->progs.stream_arena_write_fault, &skel->bss->fault_addr);
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arena_stream__destroy(skel);
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}

‎tools/testing/selftests/bpf/prog_tests/stream.c‎

Lines changed: 0 additions & 48 deletions
Original file line numberDiff line numberDiff line change
@@ -58,51 +58,3 @@ void test_stream_syscall(void)
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stream__destroy(skel);
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}
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61-
static void test_address(struct bpf_program *prog, unsigned long *fault_addr_p)
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{
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LIBBPF_OPTS(bpf_test_run_opts, opts);
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LIBBPF_OPTS(bpf_prog_stream_read_opts, ropts);
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int ret, prog_fd;
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char fault_addr[64];
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char buf[1024];
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prog_fd = bpf_program__fd(prog);
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ret = bpf_prog_test_run_opts(prog_fd, &opts);
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ASSERT_OK(ret, "ret");
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ASSERT_OK(opts.retval, "retval");
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sprintf(fault_addr, "0x%lx", *fault_addr_p);
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ret = bpf_prog_stream_read(prog_fd, BPF_STREAM_STDERR, buf, sizeof(buf), &ropts);
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ASSERT_GT(ret, 0, "stream read");
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ASSERT_LE(ret, 1023, "len for buf");
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buf[ret] = '\0';
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if (!ASSERT_HAS_SUBSTR(buf, fault_addr, "fault_addr")) {
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fprintf(stderr, "Output from stream:\n%s\n", buf);
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fprintf(stderr, "Fault Addr: %s\n", fault_addr);
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}
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}
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void test_stream_arena_fault_address(void)
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{
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struct stream *skel;
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#if !defined(__x86_64__) && !defined(__aarch64__)
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printf("%s:SKIP: arena fault reporting not supported\n", __func__);
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test__skip();
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return;
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#endif
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skel = stream__open_and_load();
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if (!ASSERT_OK_PTR(skel, "stream__open_and_load"))
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return;
101-
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if (test__start_subtest("read_fault"))
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test_address(skel->progs.stream_arena_read_fault, &skel->bss->fault_addr);
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if (test__start_subtest("write_fault"))
105-
test_address(skel->progs.stream_arena_write_fault, &skel->bss->fault_addr);
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stream__destroy(skel);
108-
}

‎tools/testing/selftests/bpf/progs/arena_stream.c‎

Lines changed: 151 additions & 0 deletions
Original file line numberDiff line numberDiff line change
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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
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#include <vmlinux.h>
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#include <bpf/bpf_tracing.h>
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#include <bpf/bpf_helpers.h>
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#include "bpf_misc.h"
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#include "bpf_experimental.h"
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#include "bpf_arena_common.h"
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struct {
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__uint(type, BPF_MAP_TYPE_ARENA);
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__uint(map_flags, BPF_F_MMAPABLE);
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__uint(max_entries, 1); /* number of pages */
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} arena SEC(".maps");
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struct elem {
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struct bpf_timer timer;
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};
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__uint(max_entries, 1);
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__type(key, int);
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__type(value, struct elem);
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} array SEC(".maps");
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u64 fault_addr;
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void *arena_ptr;
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SEC("syscall")
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__arch_x86_64
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__arch_arm64
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__success __retval(0)
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__stderr("ERROR: Arena WRITE access at unmapped address 0x{{.*}}")
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__stderr("CPU: {{[0-9]+}} UID: 0 PID: {{[0-9]+}} Comm: {{.*}}")
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__stderr("Call trace:\n"
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"{{([a-zA-Z_][a-zA-Z0-9_]*\\+0x[0-9a-fA-F]+/0x[0-9a-fA-F]+\n"
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"|[ \t]+[^\n]+\n)*}}")
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int stream_arena_write_fault(void *ctx)
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{
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struct bpf_arena *ptr = (void *)&arena;
42+
u64 user_vm_start;
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/* Prevent GCC bounds warning: casting &arena to struct bpf_arena *
45+
* triggers bounds checking since the map definition is smaller than struct
46+
* bpf_arena. barrier_var() makes the pointer opaque to GCC, preventing the
47+
* bounds analysis
48+
*/
49+
barrier_var(ptr);
50+
user_vm_start = ptr->user_vm_start;
51+
fault_addr = user_vm_start + 0x7fff;
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bpf_addr_space_cast(user_vm_start, 0, 1);
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asm volatile (
54+
"r1 = %0;"
55+
"r2 = 1;"
56+
"*(u32 *)(r1 + 0x7fff) = r2;"
57+
:
58+
: "r" (user_vm_start)
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: "r1", "r2"
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);
61+
return 0;
62+
}
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64+
SEC("syscall")
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__arch_x86_64
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__arch_arm64
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__success __retval(0)
68+
__stderr("ERROR: Arena READ access at unmapped address 0x{{.*}}")
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__stderr("CPU: {{[0-9]+}} UID: 0 PID: {{[0-9]+}} Comm: {{.*}}")
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__stderr("Call trace:\n"
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"{{([a-zA-Z_][a-zA-Z0-9_]*\\+0x[0-9a-fA-F]+/0x[0-9a-fA-F]+\n"
72+
"|[ \t]+[^\n]+\n)*}}")
73+
int stream_arena_read_fault(void *ctx)
74+
{
75+
struct bpf_arena *ptr = (void *)&arena;
76+
u64 user_vm_start;
77+
78+
/* Prevent GCC bounds warning: casting &arena to struct bpf_arena *
79+
* triggers bounds checking since the map definition is smaller than struct
80+
* bpf_arena. barrier_var() makes the pointer opaque to GCC, preventing the
81+
* bounds analysis
82+
*/
83+
barrier_var(ptr);
84+
user_vm_start = ptr->user_vm_start;
85+
fault_addr = user_vm_start + 0x7fff;
86+
bpf_addr_space_cast(user_vm_start, 0, 1);
87+
asm volatile (
88+
"r1 = %0;"
89+
"r1 = *(u32 *)(r1 + 0x7fff);"
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:
91+
: "r" (user_vm_start)
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: "r1"
93+
);
94+
return 0;
95+
}
96+
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static __noinline void subprog(void)
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{
99+
int __arena *addr = (int __arena *)0xdeadbeef;
100+
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arena_ptr = &arena;
102+
*addr = 1;
103+
}
104+
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SEC("syscall")
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__arch_x86_64
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__arch_arm64
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__success __retval(0)
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__stderr("ERROR: Arena WRITE access at unmapped address 0x{{.*}}")
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__stderr("CPU: {{[0-9]+}} UID: 0 PID: {{[0-9]+}} Comm: {{.*}}")
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__stderr("Call trace:\n"
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"{{([a-zA-Z_][a-zA-Z0-9_]*\\+0x[0-9a-fA-F]+/0x[0-9a-fA-F]+\n"
113+
"|[ \t]+[^\n]+\n)*}}")
114+
int stream_arena_subprog_fault(void *ctx)
115+
{
116+
subprog();
117+
return 0;
118+
}
119+
120+
static __noinline int timer_cb(void *map, int *key, struct bpf_timer *timer)
121+
{
122+
int __arena *addr = (int __arena *)0xdeadbeef;
123+
124+
arena_ptr = &arena;
125+
*addr = 1;
126+
return 0;
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}
128+
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SEC("syscall")
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__arch_x86_64
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__arch_arm64
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__success __retval(0)
133+
__stderr("ERROR: Arena WRITE access at unmapped address 0x{{.*}}")
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__stderr("CPU: {{[0-9]+}} UID: 0 PID: {{[0-9]+}} Comm: {{.*}}")
135+
__stderr("Call trace:\n"
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"{{([a-zA-Z_][a-zA-Z0-9_]*\\+0x[0-9a-fA-F]+/0x[0-9a-fA-F]+\n"
137+
"|[ \t]+[^\n]+\n)*}}")
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int stream_arena_callback_fault(void *ctx)
139+
{
140+
struct bpf_timer *arr_timer;
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142+
arr_timer = bpf_map_lookup_elem(&array, &(int){0});
143+
if (!arr_timer)
144+
return 0;
145+
bpf_timer_init(arr_timer, &array, 1);
146+
bpf_timer_set_callback(arr_timer, timer_cb);
147+
bpf_timer_start(arr_timer, 0, 0);
148+
return 0;
149+
}
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char _license[] SEC("license") = "GPL";

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