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bpf: Add bpf_prog_run_array_sleepable()

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Add bpf_prog_run_array_sleepable() for running BPF program arrays
on faultable tracepoints. Unlike bpf_prog_run_array_uprobe(), it
includes per-program recursion checking for private stack safety
and hardcodes is_uprobe to false.

Skip dummy_bpf_prog at the top of the loop. When
bpf_prog_array_delete_safe() replaces a detached program with
dummy_bpf_prog on allocation failure, the dummy is statically
allocated and has NULL active, stats, and aux fields. Identify
it by prog->len == 0, since every real program has at least one
instruction.

Keep bpf_prog_run_array_uprobe() unchanged for uprobe callers.

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/20260422-sleepable_tracepoints-v13-2-99005dff21ef@meta.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
This commit is contained in:
Mykyta Yatsenko 2026-04-22 12:41:07 -07:00 committed by Kumar Kartikeya Dwivedi
parent 439ebd5b57
commit 12628ffaf9
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1 changed files with 50 additions and 0 deletions
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50
include/linux/bpf.h
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@ -3079,6 +3079,56 @@ void bpf_dynptr_set_null(struct bpf_dynptr_kern *ptr);
void bpf_dynptr_set_rdonly(struct bpf_dynptr_kern *ptr);
void bpf_prog_report_arena_violation(bool write, unsigned long addr, unsigned long fault_ip);
static __always_inline u32
bpf_prog_run_array_sleepable(const struct bpf_prog_array *array,
const void *ctx, bpf_prog_run_fn run_prog)
{
const struct bpf_prog_array_item *item;
struct bpf_prog *prog;
struct bpf_run_ctx *old_run_ctx;
struct bpf_trace_run_ctx run_ctx;
u32 ret = 1;
if (unlikely(!array))
return ret;
migrate_disable();
run_ctx.is_uprobe = false;
old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
item = &array->items[0];
while ((prog = READ_ONCE(item->prog))) {
/* Skip dummy_bpf_prog placeholder (len == 0) */
if (unlikely(!prog->len)) {
item++;
continue;
}
if (unlikely(!bpf_prog_get_recursion_context(prog))) {
bpf_prog_inc_misses_counter(prog);
bpf_prog_put_recursion_context(prog);
item++;
continue;
}
run_ctx.bpf_cookie = item->bpf_cookie;
if (!prog->sleepable) {
guard(rcu)();
ret &= run_prog(prog, ctx);
} else {
ret &= run_prog(prog, ctx);
}
bpf_prog_put_recursion_context(prog);
item++;
}
bpf_reset_run_ctx(old_run_ctx);
migrate_enable();
return ret;
}
#else /* !CONFIG_BPF_SYSCALL */
static inline struct bpf_prog *bpf_prog_get(u32 ufd)
{