diff options
authorWang Nan <>2016-05-24 09:21:28 +0000
committerArnaldo Carvalho de Melo <>2016-05-27 09:41:39 -0300
commit3dc6c1d54ff4cc9ce7e8513c286c970304cde20b (patch)
parent38272dc4f1b17437871b786d567e1242d0904f5a (diff)
perf record: Fix crash when kptr is restricted
Before this patch, a simple 'perf record' could fail if kptr_restrict is set to 1 (for normal user) or 2 (for root): # perf record ls WARNING: Kernel address maps (/proc/{kallsyms,modules}) are restricted, check /proc/sys/kernel/kptr_restrict. Samples in kernel functions may not be resolved if a suitable vmlinux file is not found in the buildid cache or in the vmlinux path. Samples in kernel modules won't be resolved at all. If some relocation was applied (e.g. kexec) symbols may be misresolved even with a suitable vmlinux or kallsyms file. Segmentation fault (core dumped) This patch skips perf_event__synthesize_kernel_mmap() when kptr is not available. Signed-off-by: Wang Nan <> Tested-by: Arnaldo Carvalho de Melo <> Fixes: 45e90056904b ("perf machine: Do not bail out if not managing to read ref reloc symbol") Cc: Zefan Li <> Cc: Link: Signed-off-by: Arnaldo Carvalho de Melo <>
1 files changed, 2 insertions, 0 deletions
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index f6fcc6832949..9b141f12329e 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -673,6 +673,8 @@ int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
int err;
union perf_event *event;
+ if (symbol_conf.kptr_restrict)
+ return -1;
if (map == NULL)
return -1;