Commit 60a3e3b9 authored by Thomas Richter's avatar Thomas Richter Committed by Greg Kroah-Hartman
Browse files

perf record: Fix s390 missing module symbol and warning for non-root users

[ Upstream commit 6738028d ]

Command 'perf record' and 'perf report' on a system without kernel
debuginfo packages uses /proc/kallsyms and /proc/modules to find
addresses for kernel and module symbols. On x86 this works for root and
non-root users.

On s390, when invoked as non-root user, many of the following warnings
are shown and module symbols are missing:

    proc/{kallsyms,modules} inconsistency while looking for
        "[sha1_s390]" module!

Command 'perf record' creates a list of module start addresses by
parsing the output of /proc/modules and creates a PERF_RECORD_MMAP
record for the kernel and each module. The following function call
sequence is executed:

  machine__create_kernel_maps
    machine__create_module
      modules__parse
        machine__create_module --> for each line in /proc/modules
          arch__fix_module_text_start

Function arch__fix_module_text_start() is s390 spec...
parent be0e6266
......@@ -5,16 +5,19 @@
#include "util.h"
#include "machine.h"
#include "api/fs/fs.h"
#include "debug.h"
int arch__fix_module_text_start(u64 *start, const char *name)
{
u64 m_start = *start;
char path[PATH_MAX];
snprintf(path, PATH_MAX, "module/%.*s/sections/.text",
(int)strlen(name) - 2, name + 1);
if (sysfs__read_ull(path, (unsigned long long *)start) < 0)
return -1;
if (sysfs__read_ull(path, (unsigned long long *)start) < 0) {
pr_debug2("Using module %s start:%#lx\n", path, m_start);
*start = m_start;
}
return 0;
}
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