| Message ID | 20201203035204.1411380-2-andrii@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | Support BTF-powered BPF tracing programs for kernel modules | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Clearly marked for bpf-next |
| netdev/subject_prefix | success | Link |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 33 this patch: 33 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 15 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 33 this patch: 33 |
| netdev/header_inline | success | Link |
| netdev/stable | success | Stable not CCed |
Andrii Nakryiko wrote: > __module_address() needs to be called with preemption disabled or with > module_mutex taken. preempt_disable() is enough for read-only uses, which is > what this fix does. Also, module_put() does internal check for NULL, so drop > it as well. > > Fixes: a38d1107f937 ("bpf: support raw tracepoints in modules") > Acked-by: Martin KaFai Lau <kafai@fb.com> > Signed-off-by: Andrii Nakryiko <andrii@kernel.org> > --- Acked-by: John Fastabend <john.fastabend@gmail.com>
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index d255bc9b2bfa..23a390aac524 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2060,10 +2060,12 @@ struct bpf_raw_event_map *bpf_get_raw_tracepoint(const char *name) void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp) { - struct module *mod = __module_address((unsigned long)btp); + struct module *mod; - if (mod) - module_put(mod); + preempt_disable(); + mod = __module_address((unsigned long)btp); + module_put(mod); + preempt_enable(); } static __always_inline
__module_address() needs to be called with preemption disabled or with module_mutex taken. preempt_disable() is enough for read-only uses, which is what this fix does. Also, module_put() does internal check for NULL, so drop it as well. Fixes: a38d1107f937 ("bpf: support raw tracepoints in modules") Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> --- kernel/trace/bpf_trace.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)