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872523233d
When clang is not linked with 'perf' we should just add a debug message
about that before doing the fallback to calling the external compiler.
I.e. just the "-95" warning below gets turned into a debug message:
# cat sys_enter_open.c
#include "bpf.h"
SEC("syscalls:sys_enter_open")
int func(void *ctx)
{
struct {
char *ptr;
char path[256];
} filename = {
.ptr = *((char **)(ctx + 16)),
};
int len = bpf_probe_read_str(filename.path, sizeof(filename.path), filename.ptr);
if (len > 0) {
if (len == 1)
perf_event_output(ctx, &__bpf_stdout__, BPF_F_CURRENT_CPU, &filename, len + sizeof(filename.ptr));
else if (len < 256)
perf_event_output(ctx, &__bpf_stdout__, BPF_F_CURRENT_CPU, &filename, len + sizeof(filename.ptr));
}
return 0;
}
# trace -e open,sys_enter_open.c
bpf: builtin compilation failed: -95, try external compiler
0.000 ( ): __bpf_stdout__:@......./proc/self/task/11160/comm..)
0.014 ( 0.116 ms): qemu-system-x8/6721 open(filename: /proc/self/task/11160/comm, flags: RDWR) = 91
2335.411 ( ): __bpf_stdout__:FB..~.../etc/resolv.conf....)
2335.421 ( 0.030 ms): chronyd/883 open(filename: /etc/resolv.conf, flags: CLOEXEC) = 5
^C#
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-z5aak9oay448ffj37giz94yr@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.