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-rw-r--r--include/linux/bpf_verifier.h5
-rw-r--r--kernel/bpf/verifier.c274
-rw-r--r--tools/testing/selftests/bpf/progs/cb_refs.c1
-rw-r--r--tools/testing/selftests/bpf/progs/exceptions_fail.c2
-rw-r--r--tools/testing/selftests/bpf/progs/verifier_subprog_precision.c71
5 files changed, 240 insertions, 113 deletions
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 24213a99cc79..dd326936dd6f 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -400,6 +400,7 @@ struct bpf_verifier_state {
struct bpf_idx_pair *jmp_history;
u32 jmp_history_cnt;
u32 dfs_depth;
+ u32 callback_unroll_depth;
};
#define bpf_get_spilled_reg(slot, frame, mask) \
@@ -511,6 +512,10 @@ struct bpf_insn_aux_data {
* this instruction, regardless of any heuristics
*/
bool force_checkpoint;
+ /* true if instruction is a call to a helper function that
+ * accepts callback function as a parameter.
+ */
+ bool calls_callback;
};
#define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program */
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 68ee4803d3a2..a60dfa56ebb3 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -547,13 +547,12 @@ static bool is_dynptr_ref_function(enum bpf_func_id func_id)
return func_id == BPF_FUNC_dynptr_data;
}
-static bool is_callback_calling_kfunc(u32 btf_id);
+static bool is_sync_callback_calling_kfunc(u32 btf_id);
static bool is_bpf_throw_kfunc(struct bpf_insn *insn);
-static bool is_callback_calling_function(enum bpf_func_id func_id)
+static bool is_sync_callback_calling_function(enum bpf_func_id func_id)
{
return func_id == BPF_FUNC_for_each_map_elem ||
- func_id == BPF_FUNC_timer_set_callback ||
func_id == BPF_FUNC_find_vma ||
func_id == BPF_FUNC_loop ||
func_id == BPF_FUNC_user_ringbuf_drain;
@@ -564,6 +563,18 @@ static bool is_async_callback_calling_function(enum bpf_func_id func_id)
return func_id == BPF_FUNC_timer_set_callback;
}
+static bool is_callback_calling_function(enum bpf_func_id func_id)
+{
+ return is_sync_callback_calling_function(func_id) ||
+ is_async_callback_calling_function(func_id);
+}
+
+static bool is_sync_callback_calling_insn(struct bpf_insn *insn)
+{
+ return (bpf_helper_call(insn) && is_sync_callback_calling_function(insn->imm)) ||
+ (bpf_pseudo_kfunc_call(insn) && is_sync_callback_calling_kfunc(insn->imm));
+}
+
static bool is_storage_get_function(enum bpf_func_id func_id)
{
return func_id == BPF_FUNC_sk_storage_get ||
@@ -1808,6 +1819,7 @@ static int copy_verifier_state(struct bpf_verifier_state *dst_state,
dst_state->first_insn_idx = src->first_insn_idx;
dst_state->last_insn_idx = src->last_insn_idx;
dst_state->dfs_depth = src->dfs_depth;
+ dst_state->callback_unroll_depth = src->callback_unroll_depth;
dst_state->used_as_loop_entry = src->used_as_loop_entry;
for (i = 0; i <= src->curframe; i++) {
dst = dst_state->frame[i];
@@ -3731,6 +3743,8 @@ static void fmt_stack_mask(char *buf, ssize_t buf_sz, u64 stack_mask)
}
}
+static bool calls_callback(struct bpf_verifier_env *env, int insn_idx);
+
/* For given verifier state backtrack_insn() is called from the last insn to
* the first insn. Its purpose is to compute a bitmask of registers and
* stack slots that needs precision in the parent verifier state.
@@ -3906,16 +3920,13 @@ static int backtrack_insn(struct bpf_verifier_env *env, int idx, int subseq_idx,
return -EFAULT;
return 0;
}
- } else if ((bpf_helper_call(insn) &&
- is_callback_calling_function(insn->imm) &&
- !is_async_callback_calling_function(insn->imm)) ||
- (bpf_pseudo_kfunc_call(insn) && is_callback_calling_kfunc(insn->imm))) {
- /* callback-calling helper or kfunc call, which means
- * we are exiting from subprog, but unlike the subprog
- * call handling above, we shouldn't propagate
- * precision of r1-r5 (if any requested), as they are
- * not actually arguments passed directly to callback
- * subprogs
+ } else if (is_sync_callback_calling_insn(insn) && idx != subseq_idx - 1) {
+ /* exit from callback subprog to callback-calling helper or
+ * kfunc call. Use idx/subseq_idx check to discern it from
+ * straight line code backtracking.
+ * Unlike the subprog call handling above, we shouldn't
+ * propagate precision of r1-r5 (if any requested), as they are
+ * not actually arguments passed directly to callback subprogs
*/
if (bt_reg_mask(bt) & ~BPF_REGMASK_ARGS) {
verbose(env, "BUG regs %x\n", bt_reg_mask(bt));
@@ -3950,10 +3961,18 @@ static int backtrack_insn(struct bpf_verifier_env *env, int idx, int subseq_idx,
} else if (opcode == BPF_EXIT) {
bool r0_precise;
+ /* Backtracking to a nested function call, 'idx' is a part of
+ * the inner frame 'subseq_idx' is a part of the outer frame.
+ * In case of a regular function call, instructions giving
+ * precision to registers R1-R5 should have been found already.
+ * In case of a callback, it is ok to have R1-R5 marked for
+ * backtracking, as these registers are set by the function
+ * invoking callback.
+ */
+ if (subseq_idx >= 0 && calls_callback(env, subseq_idx))
+ for (i = BPF_REG_1; i <= BPF_REG_5; i++)
+ bt_clear_reg(bt, i);
if (bt_reg_mask(bt) & BPF_REGMASK_ARGS) {
- /* if backtracing was looking for registers R1-R5
- * they should have been found already.
- */
verbose(env, "BUG regs %x\n", bt_reg_mask(bt));
WARN_ONCE(1, "verifier backtracking bug");
return -EFAULT;
@@ -9421,11 +9440,11 @@ err_out:
return err;
}
-static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
- int *insn_idx, int subprog,
- set_callee_state_fn set_callee_state_cb)
+static int push_callback_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
+ int insn_idx, int subprog,
+ set_callee_state_fn set_callee_state_cb)
{
- struct bpf_verifier_state *state = env->cur_state;
+ struct bpf_verifier_state *state = env->cur_state, *callback_state;
struct bpf_func_state *caller, *callee;
int err;
@@ -9433,44 +9452,22 @@ static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn
err = btf_check_subprog_call(env, subprog, caller->regs);
if (err == -EFAULT)
return err;
- if (subprog_is_global(env, subprog)) {
- if (err) {
- verbose(env, "Caller passes invalid args into func#%d\n",
- subprog);
- return err;
- } else {
- if (env->log.level & BPF_LOG_LEVEL)
- verbose(env,
- "Func#%d is global and valid. Skipping.\n",
- subprog);
- clear_caller_saved_regs(env, caller->regs);
-
- /* All global functions return a 64-bit SCALAR_VALUE */
- mark_reg_unknown(env, caller->regs, BPF_REG_0);
- caller->regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG;
-
- /* continue with next insn after call */
- return 0;
- }
- }
/* set_callee_state is used for direct subprog calls, but we are
* interested in validating only BPF helpers that can call subprogs as
* callbacks
*/
- if (set_callee_state_cb != set_callee_state) {
- env->subprog_info[subprog].is_cb = true;
- if (bpf_pseudo_kfunc_call(insn) &&
- !is_callback_calling_kfunc(insn->imm)) {
- verbose(env, "verifier bug: kfunc %s#%d not marked as callback-calling\n",
- func_id_name(insn->imm), insn->imm);
- return -EFAULT;
- } else if (!bpf_pseudo_kfunc_call(insn) &&
- !is_callback_calling_function(insn->imm)) { /* helper */
- verbose(env, "verifier bug: helper %s#%d not marked as callback-calling\n",
- func_id_name(insn->imm), insn->imm);
- return -EFAULT;
- }
+ env->subprog_info[subprog].is_cb = true;
+ if (bpf_pseudo_kfunc_call(insn) &&
+ !is_sync_callback_calling_kfunc(insn->imm)) {
+ verbose(env, "verifier bug: kfunc %s#%d not marked as callback-calling\n",
+ func_id_name(insn->imm), insn->imm);
+ return -EFAULT;
+ } else if (!bpf_pseudo_kfunc_call(insn) &&
+ !is_callback_calling_function(insn->imm)) { /* helper */
+ verbose(env, "verifier bug: helper %s#%d not marked as callback-calling\n",
+ func_id_name(insn->imm), insn->imm);
+ return -EFAULT;
}
if (insn->code == (BPF_JMP | BPF_CALL) &&
@@ -9481,25 +9478,76 @@ static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn
/* there is no real recursion here. timer callbacks are async */
env->subprog_info[subprog].is_async_cb = true;
async_cb = push_async_cb(env, env->subprog_info[subprog].start,
- *insn_idx, subprog);
+ insn_idx, subprog);
if (!async_cb)
return -EFAULT;
callee = async_cb->frame[0];
callee->async_entry_cnt = caller->async_entry_cnt + 1;
/* Convert bpf_timer_set_callback() args into timer callback args */
- err = set_callee_state_cb(env, caller, callee, *insn_idx);
+ err = set_callee_state_cb(env, caller, callee, insn_idx);
if (err)
return err;
+ return 0;
+ }
+
+ /* for callback functions enqueue entry to callback and
+ * proceed with next instruction within current frame.
+ */
+ callback_state = push_stack(env, env->subprog_info[subprog].start, insn_idx, false);
+ if (!callback_state)
+ return -ENOMEM;
+
+ err = setup_func_entry(env, subprog, insn_idx, set_callee_state_cb,
+ callback_state);
+ if (err)
+ return err;
+
+ callback_state->callback_unroll_depth++;
+ return 0;
+}
+
+static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
+ int *insn_idx)
+{
+ struct bpf_verifier_state *state = env->cur_state;
+ struct bpf_func_state *caller;
+ int err, subprog, target_insn;
+
+ target_insn = *insn_idx + insn->imm + 1;
+ subprog = find_subprog(env, target_insn);
+ if (subprog < 0) {
+ verbose(env, "verifier bug. No program starts at insn %d\n", target_insn);
+ return -EFAULT;
+ }
+
+ caller = state->frame[state->curframe];
+ err = btf_check_subprog_call(env, subprog, caller->regs);
+ if (err == -EFAULT)
+ return err;
+ if (subprog_is_global(env, subprog)) {
+ if (err) {
+ verbose(env, "Caller passes invalid args into func#%d\n", subprog);
+ return err;
+ }
+
+ if (env->log.level & BPF_LOG_LEVEL)
+ verbose(env, "Func#%d is global and valid. Skipping.\n", subprog);
clear_caller_saved_regs(env, caller->regs);
+
+ /* All global functions return a 64-bit SCALAR_VALUE */
mark_reg_unknown(env, caller->regs, BPF_REG_0);
caller->regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG;
+
/* continue with next insn after call */
return 0;
}
- err = setup_func_entry(env, subprog, *insn_idx, set_callee_state_cb, state);
+ /* for regular function entry setup new frame and continue
+ * from that frame.
+ */
+ err = setup_func_entry(env, subprog, *insn_idx, set_callee_state, state);
if (err)
return err;
@@ -9559,22 +9607,6 @@ static int set_callee_state(struct bpf_verifier_env *env,
return 0;
}
-static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
- int *insn_idx)
-{
- int subprog, target_insn;
-
- target_insn = *insn_idx + insn->imm + 1;
- subprog = find_subprog(env, target_insn);
- if (subprog < 0) {
- verbose(env, "verifier bug. No program starts at insn %d\n",
- target_insn);
- return -EFAULT;
- }
-
- return __check_func_call(env, insn, insn_idx, subprog, set_callee_state);
-}
-
static int set_map_elem_callback_state(struct bpf_verifier_env *env,
struct bpf_func_state *caller,
struct bpf_func_state *callee,
@@ -9798,6 +9830,11 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx)
verbose_invalid_scalar(env, r0, &range, "callback return", "R0");
return -EINVAL;
}
+ if (!calls_callback(env, callee->callsite)) {
+ verbose(env, "BUG: in callback at %d, callsite %d !calls_callback\n",
+ *insn_idx, callee->callsite);
+ return -EFAULT;
+ }
} else {
/* return to the caller whatever r0 had in the callee */
caller->regs[BPF_REG_0] = *r0;
@@ -9815,7 +9852,15 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx)
return err;
}
- *insn_idx = callee->callsite + 1;
+ /* for callbacks like bpf_loop or bpf_for_each_map_elem go back to callsite,
+ * there function call logic would reschedule callback visit. If iteration
+ * converges is_state_visited() would prune that visit eventually.
+ */
+ if (callee->in_callback_fn)
+ *insn_idx = callee->callsite;
+ else
+ *insn_idx = callee->callsite + 1;
+
if (env->log.level & BPF_LOG_LEVEL) {
verbose(env, "returning from callee:\n");
print_verifier_state(env, callee, true);
@@ -10228,24 +10273,24 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
}
break;
case BPF_FUNC_for_each_map_elem:
- err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
- set_map_elem_callback_state);
+ err = push_callback_call(env, insn, insn_idx, meta.subprogno,
+ set_map_elem_callback_state);
break;
case BPF_FUNC_timer_set_callback:
- err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
- set_timer_callback_state);
+ err = push_callback_call(env, insn, insn_idx, meta.subprogno,
+ set_timer_callback_state);
break;
case BPF_FUNC_find_vma:
- err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
- set_find_vma_callback_state);
+ err = push_callback_call(env, insn, insn_idx, meta.subprogno,
+ set_find_vma_callback_state);
break;
case BPF_FUNC_snprintf:
err = check_bpf_snprintf_call(env, regs);
break;
case BPF_FUNC_loop:
update_loop_inline_state(env, meta.subprogno);
- err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
- set_loop_callback_state);
+ err = push_callback_call(env, insn, insn_idx, meta.subprogno,
+ set_loop_callback_state);
break;
case BPF_FUNC_dynptr_from_mem:
if (regs[BPF_REG_1].type != PTR_TO_MAP_VALUE) {
@@ -10341,8 +10386,8 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
break;
}
case BPF_FUNC_user_ringbuf_drain:
- err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
- set_user_ringbuf_callback_state);
+ err = push_callback_call(env, insn, insn_idx, meta.subprogno,
+ set_user_ringbuf_callback_state);
break;
}
@@ -11230,7 +11275,7 @@ static bool is_bpf_graph_api_kfunc(u32 btf_id)
btf_id == special_kfunc_list[KF_bpf_refcount_acquire_impl];
}
-static bool is_callback_calling_kfunc(u32 btf_id)
+static bool is_sync_callback_calling_kfunc(u32 btf_id)
{
return btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl];
}
@@ -11982,6 +12027,21 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
return -EACCES;
}
+ /* Check the arguments */
+ err = check_kfunc_args(env, &meta, insn_idx);
+ if (err < 0)
+ return err;
+
+ if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
+ err = push_callback_call(env, insn, insn_idx, meta.subprogno,
+ set_rbtree_add_callback_state);
+ if (err) {
+ verbose(env, "kfunc %s#%d failed callback verification\n",
+ func_name, meta.func_id);
+ return err;
+ }
+ }
+
rcu_lock = is_kfunc_bpf_rcu_read_lock(&meta);
rcu_unlock = is_kfunc_bpf_rcu_read_unlock(&meta);
@@ -12017,10 +12077,6 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
return -EINVAL;
}
- /* Check the arguments */
- err = check_kfunc_args(env, &meta, insn_idx);
- if (err < 0)
- return err;
/* In case of release function, we get register number of refcounted
* PTR_TO_BTF_ID in bpf_kfunc_arg_meta, do the release now.
*/
@@ -12054,16 +12110,6 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
}
}
- if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
- err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
- set_rbtree_add_callback_state);
- if (err) {
- verbose(env, "kfunc %s#%d failed callback verification\n",
- func_name, meta.func_id);
- return err;
- }
- }
-
if (meta.func_id == special_kfunc_list[KF_bpf_throw]) {
if (!bpf_jit_supports_exceptions()) {
verbose(env, "JIT does not support calling kfunc %s#%d\n",
@@ -15427,6 +15473,15 @@ static bool is_force_checkpoint(struct bpf_verifier_env *env, int insn_idx)
return env->insn_aux_data[insn_idx].force_checkpoint;
}
+static void mark_calls_callback(struct bpf_verifier_env *env, int idx)
+{
+ env->insn_aux_data[idx].calls_callback = true;
+}
+
+static bool calls_callback(struct bpf_verifier_env *env, int insn_idx)
+{
+ return env->insn_aux_data[insn_idx].calls_callback;
+}
enum {
DONE_EXPLORING = 0,
@@ -15540,6 +15595,21 @@ static int visit_insn(int t, struct bpf_verifier_env *env)
* async state will be pushed for further exploration.
*/
mark_prune_point(env, t);
+ /* For functions that invoke callbacks it is not known how many times
+ * callback would be called. Verifier models callback calling functions
+ * by repeatedly visiting callback bodies and returning to origin call
+ * instruction.
+ * In order to stop such iteration verifier needs to identify when a
+ * state identical some state from a previous iteration is reached.
+ * Check below forces creation of checkpoint before callback calling
+ * instruction to allow search for such identical states.
+ */
+ if (is_sync_callback_calling_insn(insn)) {
+ mark_calls_callback(env, t);
+ mark_force_checkpoint(env, t);
+ mark_prune_point(env, t);
+ mark_jmp_point(env, t);
+ }
if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
struct bpf_kfunc_call_arg_meta meta;
@@ -17009,10 +17079,16 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
}
goto skip_inf_loop_check;
}
+ if (calls_callback(env, insn_idx)) {
+ if (states_equal(env, &sl->state, cur, true))
+ goto hit;
+ goto skip_inf_loop_check;
+ }
/* attempt to detect infinite loop to avoid unnecessary doomed work */
if (states_maybe_looping(&sl->state, cur) &&
states_equal(env, &sl->state, cur, false) &&
- !iter_active_depths_differ(&sl->state, cur)) {
+ !iter_active_depths_differ(&sl->state, cur) &&
+ sl->state.callback_unroll_depth == cur->callback_unroll_depth) {
verbose_linfo(env, insn_idx, "; ");
verbose(env, "infinite loop detected at insn %d\n", insn_idx);
verbose(env, "cur state:");
diff --git a/tools/testing/selftests/bpf/progs/cb_refs.c b/tools/testing/selftests/bpf/progs/cb_refs.c
index 76d661b20e87..56c764df8196 100644
--- a/tools/testing/selftests/bpf/progs/cb_refs.c
+++ b/tools/testing/selftests/bpf/progs/cb_refs.c
@@ -33,6 +33,7 @@ int underflow_prog(void *ctx)
if (!p)
return 0;
bpf_for_each_map_elem(&array_map, cb1, &p, 0);
+ bpf_kfunc_call_test_release(p);
return 0;
}
diff --git a/tools/testing/selftests/bpf/progs/exceptions_fail.c b/tools/testing/selftests/bpf/progs/exceptions_fail.c
index 4c39e920dac2..8c0ef2742208 100644
--- a/tools/testing/selftests/bpf/progs/exceptions_fail.c
+++ b/tools/testing/selftests/bpf/progs/exceptions_fail.c
@@ -171,6 +171,7 @@ int reject_with_rbtree_add_throw(void *ctx)
return 0;
bpf_spin_lock(&lock);
bpf_rbtree_add(&rbtree, &f->node, rbless);
+ bpf_spin_unlock(&lock);
return 0;
}
@@ -214,6 +215,7 @@ int reject_with_cb_reference(void *ctx)
if (!f)
return 0;
bpf_loop(5, subprog_cb_ref, NULL, 0);
+ bpf_obj_drop(f);
return 0;
}
diff --git a/tools/testing/selftests/bpf/progs/verifier_subprog_precision.c b/tools/testing/selftests/bpf/progs/verifier_subprog_precision.c
index db6b3143338b..da803cffb5ef 100644
--- a/tools/testing/selftests/bpf/progs/verifier_subprog_precision.c
+++ b/tools/testing/selftests/bpf/progs/verifier_subprog_precision.c
@@ -119,15 +119,26 @@ __naked int global_subprog_result_precise(void)
SEC("?raw_tp")
__success __log_level(2)
+/* First simulated path does not include callback body */
__msg("14: (0f) r1 += r6")
-__msg("mark_precise: frame0: last_idx 14 first_idx 10")
+__msg("mark_precise: frame0: last_idx 14 first_idx 9")
__msg("mark_precise: frame0: regs=r6 stack= before 13: (bf) r1 = r7")
__msg("mark_precise: frame0: regs=r6 stack= before 12: (27) r6 *= 4")
__msg("mark_precise: frame0: regs=r6 stack= before 11: (25) if r6 > 0x3 goto pc+4")
__msg("mark_precise: frame0: regs=r6 stack= before 10: (bf) r6 = r0")
-__msg("mark_precise: frame0: parent state regs=r0 stack=:")
-__msg("mark_precise: frame0: last_idx 18 first_idx 0")
-__msg("mark_precise: frame0: regs=r0 stack= before 18: (95) exit")
+__msg("mark_precise: frame0: regs=r0 stack= before 9: (85) call bpf_loop")
+/* State entering callback body popped from states stack */
+__msg("from 9 to 17: frame1:")
+__msg("17: frame1: R1=scalar() R2=0 R10=fp0 cb")
+__msg("17: (b7) r0 = 0")
+__msg("18: (95) exit")
+__msg("returning from callee:")
+__msg("to caller at 9:")
+/* r4 (flags) is always precise for bpf_loop() */
+__msg("frame 0: propagating r4")
+__msg("mark_precise: frame0: last_idx 9 first_idx 9 subseq_idx -1")
+__msg("mark_precise: frame0: regs=r4 stack= before 18: (95) exit")
+__msg("from 18 to 9: safe")
__naked int callback_result_precise(void)
{
asm volatile (
@@ -233,20 +244,36 @@ __naked int parent_callee_saved_reg_precise_global(void)
SEC("?raw_tp")
__success __log_level(2)
+/* First simulated path does not include callback body */
__msg("12: (0f) r1 += r6")
-__msg("mark_precise: frame0: last_idx 12 first_idx 10")
+__msg("mark_precise: frame0: last_idx 12 first_idx 9")
__msg("mark_precise: frame0: regs=r6 stack= before 11: (bf) r1 = r7")
__msg("mark_precise: frame0: regs=r6 stack= before 10: (27) r6 *= 4")
+__msg("mark_precise: frame0: regs=r6 stack= before 9: (85) call bpf_loop")
__msg("mark_precise: frame0: parent state regs=r6 stack=:")
-__msg("mark_precise: frame0: last_idx 16 first_idx 0")
-__msg("mark_precise: frame0: regs=r6 stack= before 16: (95) exit")
-__msg("mark_precise: frame1: regs= stack= before 15: (b7) r0 = 0")
-__msg("mark_precise: frame1: regs= stack= before 9: (85) call bpf_loop#181")
+__msg("mark_precise: frame0: last_idx 8 first_idx 0 subseq_idx 9")
__msg("mark_precise: frame0: regs=r6 stack= before 8: (b7) r4 = 0")
__msg("mark_precise: frame0: regs=r6 stack= before 7: (b7) r3 = 0")
__msg("mark_precise: frame0: regs=r6 stack= before 6: (bf) r2 = r8")
__msg("mark_precise: frame0: regs=r6 stack= before 5: (b7) r1 = 1")
__msg("mark_precise: frame0: regs=r6 stack= before 4: (b7) r6 = 3")
+/* State entering callback body popped from states stack */
+__msg("from 9 to 15: frame1:")
+__msg("15: frame1: R1=scalar() R2=0 R10=fp0 cb")
+__msg("15: (b7) r0 = 0")
+__msg("16: (95) exit")
+__msg("returning from callee:")
+__msg("to caller at 9:")
+/* r4 (flags) is always precise for bpf_loop(),
+ * r6 was marked before backtracking to callback body.
+ */
+__msg("frame 0: propagating r4,r6")
+__msg("mark_precise: frame0: last_idx 9 first_idx 9 subseq_idx -1")
+__msg("mark_precise: frame0: regs=r4,r6 stack= before 16: (95) exit")
+__msg("mark_precise: frame1: regs= stack= before 15: (b7) r0 = 0")
+__msg("mark_precise: frame1: regs= stack= before 9: (85) call bpf_loop")
+__msg("mark_precise: frame0: parent state regs= stack=:")
+__msg("from 16 to 9: safe")
__naked int parent_callee_saved_reg_precise_with_callback(void)
{
asm volatile (
@@ -373,22 +400,38 @@ __naked int parent_stack_slot_precise_global(void)
SEC("?raw_tp")
__success __log_level(2)
+/* First simulated path does not include callback body */
__msg("14: (0f) r1 += r6")
-__msg("mark_precise: frame0: last_idx 14 first_idx 11")
+__msg("mark_precise: frame0: last_idx 14 first_idx 10")
__msg("mark_precise: frame0: regs=r6 stack= before 13: (bf) r1 = r7")
__msg("mark_precise: frame0: regs=r6 stack= before 12: (27) r6 *= 4")
__msg("mark_precise: frame0: regs=r6 stack= before 11: (79) r6 = *(u64 *)(r10 -8)")
+__msg("mark_precise: frame0: regs= stack=-8 before 10: (85) call bpf_loop")
__msg("mark_precise: frame0: parent state regs= stack=-8:")
-__msg("mark_precise: frame0: last_idx 18 first_idx 0")
-__msg("mark_precise: frame0: regs= stack=-8 before 18: (95) exit")
-__msg("mark_precise: frame1: regs= stack= before 17: (b7) r0 = 0")
-__msg("mark_precise: frame1: regs= stack= before 10: (85) call bpf_loop#181")
+__msg("mark_precise: frame0: last_idx 9 first_idx 0 subseq_idx 10")
__msg("mark_precise: frame0: regs= stack=-8 before 9: (b7) r4 = 0")
__msg("mark_precise: frame0: regs= stack=-8 before 8: (b7) r3 = 0")
__msg("mark_precise: frame0: regs= stack=-8 before 7: (bf) r2 = r8")
__msg("mark_precise: frame0: regs= stack=-8 before 6: (bf) r1 = r6")
__msg("mark_precise: frame0: regs= stack=-8 before 5: (7b) *(u64 *)(r10 -8) = r6")
__msg("mark_precise: frame0: regs=r6 stack= before 4: (b7) r6 = 3")
+/* State entering callback body popped from states stack */
+__msg("from 10 to 17: frame1:")
+__msg("17: frame1: R1=scalar() R2=0 R10=fp0 cb")
+__msg("17: (b7) r0 = 0")
+__msg("18: (95) exit")
+__msg("returning from callee:")
+__msg("to caller at 10:")
+/* r4 (flags) is always precise for bpf_loop(),
+ * fp-8 was marked before backtracking to callback body.
+ */
+__msg("frame 0: propagating r4,fp-8")
+__msg("mark_precise: frame0: last_idx 10 first_idx 10 subseq_idx -1")
+__msg("mark_precise: frame0: regs=r4 stack=-8 before 18: (95) exit")
+__msg("mark_precise: frame1: regs= stack= before 17: (b7) r0 = 0")
+__msg("mark_precise: frame1: regs= stack= before 10: (85) call bpf_loop#181")
+__msg("mark_precise: frame0: parent state regs= stack=:")
+__msg("from 18 to 10: safe")
__naked int parent_stack_slot_precise_with_callback(void)
{
asm volatile (
generated by cgit v1.2.3 (git 2.25.1) at 2025-02-01 06:21:37 +0000