moonjuice/kernel_arpi
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

FROMGIT: bpf: btf: limit logging of ignored BTF mismatches

Browse Source 
Enabling CONFIG_MODULE_ALLOW_BTF_MISMATCH is an indication that BTF
mismatches are expected and module loading should proceed
anyway. Logging with pr_warn() on every one of these "benign"
mismatches creates unnecessary noise when many such modules are
loaded. Instead, handle this case with a single log warning that BTF
info may be unavailable.

Mismatches also result in calls to __btf_verifier_log() via
__btf_verifier_log_type() or btf_verifier_log_member(), adding several
additional lines of logging per mismatched module. Add checks to these
paths to skip logging for module BTF mismatches in the "allow
mismatch" case.

All existing logging behavior is preserved in the default
CONFIG_MODULE_ALLOW_BTF_MISMATCH=n case.

Signed-off-by: Connor O'Brien <connoro@google.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230107025331.3240536-1-connoro@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Bug: 260025057
Bug: 256578296
Bug: 258989318
(cherry picked from commit 9cb61e50bf6bf54db712bba6cf20badca4383f96
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git
master)
Signed-off-by: Connor O'Brien <connoro@google.com>
Change-Id: I2f9d19a2027610af2e825fc38fd08f56f4cd7091
This commit is contained in:
Connor O'Brien
2023-01-07 02:53:31 +00:00
parent 80a466ef88
commit 31f50e8abc
1 changed files with 27 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

38
kernel/bpf/btf.c
View File

@@ -1300,12 +1300,18 @@ __printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
if (!bpf_verifier_log_needed(log))
return;
/* btf verifier prints all types it is processing via
* btf_verifier_log_type(..., fmt = NULL).
* Skip those prints for in-kernel BTF verification.
*/
if (log->level == BPF_LOG_KERNEL && !fmt)
return;
if (log->level == BPF_LOG_KERNEL) {
/* btf verifier prints all types it is processing via
* btf_verifier_log_type(..., fmt = NULL).
* Skip those prints for in-kernel BTF verification.
*/
if (!fmt)
return;
/* Skip logging when loading module BTF with mismatches permitted */
if (env->btf->base_btf && IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
return;
}
__btf_verifier_log(log, "[%u] %s %s%s",
env->log_type_id,
@@ -1344,8 +1350,15 @@ static void btf_verifier_log_member(struct btf_verifier_env *env,
if (!bpf_verifier_log_needed(log))
return;
if (log->level == BPF_LOG_KERNEL && !fmt)
return;
if (log->level == BPF_LOG_KERNEL) {
if (!fmt)
return;
/* Skip logging when loading module BTF with mismatches permitted */
if (env->btf->base_btf && IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
return;
}
/* The CHECK_META phase already did a btf dump.
*
* If member is logged again, it must hit an error in
@@ -6059,11 +6072,14 @@ static int btf_module_notify(struct notifier_block *nb, unsigned long op,
}
btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size);
if (IS_ERR(btf)) {
pr_warn("failed to validate module [%s] BTF: %ld\n",
mod->name, PTR_ERR(btf));
kfree(btf_mod);
if (!IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
if (!IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH)) {
pr_warn("failed to validate module [%s] BTF: %ld\n",
mod->name, PTR_ERR(btf));
err = PTR_ERR(btf);
} else {
pr_warn_once("Kernel module BTF mismatch detected, BTF debug info may be unavailable for some modules\n");
}
goto out;
}
err = btf_alloc_id(btf);