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fix build for clang18 on ubuntu 22.04 with kernel v. 5.15 #2

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fix build for clang18 on ubuntu 22.04 with kernel v. 5.15 #2

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3689961
fix Makefile: build vmlinux before generate
naushniki Jan 16, 2026
9954c65
fix build on ubuntu 22.04
naushniki Jan 16, 2026
8ef322d
fix the error "BPF program is too large"
naushniki Jan 16, 2026
6e4db23
Merge remote-tracking branch 'origin/main' into fixes
naushniki Jan 17, 2026
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2 changes: 1 addition & 1 deletion Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,7 @@ LDFLAGS := -X github.com/loresuso/psc/cmd.Version=$(VERSION) \

all: build

generate:
generate: vmlinux
go run github.com/cilium/ebpf/cmd/bpf2go -go-package main -cc clang -no-strip -target bpfel -cflags "-O2 -g -Wall -I$(LIBBPF_INCLUDE)" tasks bpf/tasks.c
go run github.com/cilium/ebpf/cmd/bpf2go -go-package main -cc clang -no-strip -target bpfel -cflags "-O2 -g -Wall -I$(LIBBPF_INCLUDE)" files bpf/files.c

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26 changes: 23 additions & 3 deletions bpf/tasks.c
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Expand Up @@ -84,6 +84,20 @@ static __always_inline void fill_task_descriptor(struct task_descriptor *td, str
td->utime = task->utime;
td->stime = task->stime;

// Capabilities from credentials
// kernel_cap_struct has cap[2] (two __u32 values), combine into __u64
struct kernel_cap_struct cap_eff = {};
struct kernel_cap_struct cap_perm = {};
struct kernel_cap_struct cap_inh = {};

bpf_probe_read_kernel(&cap_eff, sizeof(cap_eff), &task->cred->cap_effective);
bpf_probe_read_kernel(&cap_perm, sizeof(cap_perm), &task->cred->cap_permitted);
bpf_probe_read_kernel(&cap_inh, sizeof(cap_inh), &task->cred->cap_inheritable);

td->cap_effective = ((__u64)cap_eff.cap[1] << 32) | cap_eff.cap[0];
td->cap_permitted = ((__u64)cap_perm.cap[1] << 32) | cap_perm.cap[0];
td->cap_inheritable = ((__u64)cap_inh.cap[1] << 32) | cap_inh.cap[0];

td->cap_effective = read_capability(task->cred, CAP_EFFECTIVE);
td->cap_permitted = read_capability(task->cred, CAP_PERMITTED);
td->cap_inheritable = read_capability(task->cred, CAP_INHERITABLE);
Expand All @@ -97,9 +111,15 @@ static __always_inline void fill_task_descriptor(struct task_descriptor *td, str
// RSS: sum of file, anon, and shmem pages (approximation using base count)
// Note: This is the base count only, actual RSS may be slightly different
// due to per-CPU deltas in percpu_counter
rss_file = mm->rss_stat[MM_FILEPAGES].count;
rss_anon = mm->rss_stat[MM_ANONPAGES].count;
rss_shmem = mm->rss_stat[MM_SHMEMPAGES].count;
// rss_stat is a struct with count[4] array (atomic_long_t = atomic64_t)
// atomic64_t has a .counter field containing the actual value
atomic64_t count_file, count_anon, count_shmem;
bpf_probe_read_kernel(&count_file, sizeof(count_file), &mm->rss_stat.count[MM_FILEPAGES]);
rss_file = BPF_CORE_READ(&count_file, counter);
bpf_probe_read_kernel(&count_anon, sizeof(count_anon), &mm->rss_stat.count[MM_ANONPAGES]);
rss_anon = BPF_CORE_READ(&count_anon, counter);
bpf_probe_read_kernel(&count_shmem, sizeof(count_shmem), &mm->rss_stat.count[MM_SHMEMPAGES]);
rss_shmem = BPF_CORE_READ(&count_shmem, counter);

// Ensure non-negative (percpu counters can temporarily go negative)
if (rss_file < 0) rss_file = 0;
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