| Message ID | 20211021034603.4458-2-laoar.shao@gmail.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | BPF |
| Headers | show |
| Series | extend task comm from 16 to 24 for CONFIG_BASE_FULL | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
| bpf/vmtest-bpf-next-PR | fail | merge-conflict |
| bpf/vmtest-bpf | success | VM_Test |
| bpf/vmtest-bpf-PR | success | PR summary |
On Wed, Oct 20, 2021 at 8:46 PM Yafang Shao <laoar.shao@gmail.com> wrote: > > Use TASK_COMM_LEN_16 instead of hard-coded 16 to make it more grepable. > It uses bpf_probe_read_kernel() to get task comm, which may return a > string without nul terminator. We should use bpf_probe_read_kernel_str() > instead. > > Signed-off-by: Yafang Shao <laoar.shao@gmail.com> > Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> > Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Kees Cook <keescook@chromium.org> > Cc: Al Viro <viro@zeniv.linux.org.uk> > Cc: Petr Mladek <pmladek@suse.com> > --- > tools/bpf/bpftool/Makefile | 1 + > tools/bpf/bpftool/main.h | 3 ++- > tools/bpf/bpftool/skeleton/pid_iter.bpf.c | 4 ++-- > tools/bpf/bpftool/skeleton/pid_iter.h | 4 +++- > 4 files changed, 8 insertions(+), 4 deletions(-) > > diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile > index d73232be1e99..33fbde84993c 100644 > --- a/tools/bpf/bpftool/Makefile > +++ b/tools/bpf/bpftool/Makefile > @@ -164,6 +164,7 @@ $(OUTPUT)%.bpf.o: skeleton/%.bpf.c $(OUTPUT)vmlinux.h $(LIBBPF) > $(QUIET_CLANG)$(CLANG) \ > -I$(if $(OUTPUT),$(OUTPUT),.) \ > -I$(srctree)/tools/include/uapi/ \ > + -I$(srctree)/tools/include/ \ bpftool shouldn't rely on internal kernel headers for compilation. If you want to have TASK_COMM_LEN_16 constant for grep-ability, just #define it where appropriate > -I$(LIBBPF_PATH) \ > -I$(srctree)/tools/lib \ > -g -O2 -Wall -target bpf -c $< -o $@ && $(LLVM_STRIP) -g $@ > diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h > index 90caa42aac4c..5efa27188f68 100644 > --- a/tools/bpf/bpftool/main.h > +++ b/tools/bpf/bpftool/main.h > @@ -12,6 +12,7 @@ > #include <linux/compiler.h> > #include <linux/kernel.h> > #include <linux/hashtable.h> > +#include <linux/sched/task.h> > #include <tools/libc_compat.h> > [...]
diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile index d73232be1e99..33fbde84993c 100644 --- a/tools/bpf/bpftool/Makefile +++ b/tools/bpf/bpftool/Makefile @@ -164,6 +164,7 @@ $(OUTPUT)%.bpf.o: skeleton/%.bpf.c $(OUTPUT)vmlinux.h $(LIBBPF) $(QUIET_CLANG)$(CLANG) \ -I$(if $(OUTPUT),$(OUTPUT),.) \ -I$(srctree)/tools/include/uapi/ \ + -I$(srctree)/tools/include/ \ -I$(LIBBPF_PATH) \ -I$(srctree)/tools/lib \ -g -O2 -Wall -target bpf -c $< -o $@ && $(LLVM_STRIP) -g $@ diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h index 90caa42aac4c..5efa27188f68 100644 --- a/tools/bpf/bpftool/main.h +++ b/tools/bpf/bpftool/main.h @@ -12,6 +12,7 @@ #include <linux/compiler.h> #include <linux/kernel.h> #include <linux/hashtable.h> +#include <linux/sched/task.h> #include <tools/libc_compat.h> #include <bpf/libbpf.h> @@ -124,7 +125,7 @@ struct obj_refs_table { struct obj_ref { int pid; - char comm[16]; + char comm[TASK_COMM_LEN_16]; }; struct obj_refs { diff --git a/tools/bpf/bpftool/skeleton/pid_iter.bpf.c b/tools/bpf/bpftool/skeleton/pid_iter.bpf.c index d9b420972934..f70702fcb224 100644 --- a/tools/bpf/bpftool/skeleton/pid_iter.bpf.c +++ b/tools/bpf/bpftool/skeleton/pid_iter.bpf.c @@ -71,8 +71,8 @@ int iter(struct bpf_iter__task_file *ctx) e.pid = task->tgid; e.id = get_obj_id(file->private_data, obj_type); - bpf_probe_read_kernel(&e.comm, sizeof(e.comm), - task->group_leader->comm); + bpf_probe_read_kernel_str(&e.comm, sizeof(e.comm), + task->group_leader->comm); bpf_seq_write(ctx->meta->seq, &e, sizeof(e)); return 0; diff --git a/tools/bpf/bpftool/skeleton/pid_iter.h b/tools/bpf/bpftool/skeleton/pid_iter.h index 5692cf257adb..675b2916567e 100644 --- a/tools/bpf/bpftool/skeleton/pid_iter.h +++ b/tools/bpf/bpftool/skeleton/pid_iter.h @@ -3,10 +3,12 @@ #ifndef __PID_ITER_H #define __PID_ITER_H +#include <linux/sched/task.h> + struct pid_iter_entry { __u32 id; int pid; - char comm[16]; + char comm[TASK_COMM_LEN_16]; }; #endif
Use TASK_COMM_LEN_16 instead of hard-coded 16 to make it more grepable. It uses bpf_probe_read_kernel() to get task comm, which may return a string without nul terminator. We should use bpf_probe_read_kernel_str() instead. Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Kees Cook <keescook@chromium.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Petr Mladek <pmladek@suse.com> --- tools/bpf/bpftool/Makefile | 1 + tools/bpf/bpftool/main.h | 3 ++- tools/bpf/bpftool/skeleton/pid_iter.bpf.c | 4 ++-- tools/bpf/bpftool/skeleton/pid_iter.h | 4 +++- 4 files changed, 8 insertions(+), 4 deletions(-)