6.6-stable review patch. If anyone has any objections, please let me know.
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From: Ian Rogers irogers@google.com
[ Upstream commit ab8ce150781d326c6bfbe1e09f175ffde1186f80 ]
Running perf top with address sanitizer and "--call-graph=lbr" fails due to reading sample 0 when no samples exist. Add a guard to prevent this.
Fixes: e2b23483eb1d ("perf machine: Factor out lbr_callchain_add_lbr_ip()") Signed-off-by: Ian Rogers irogers@google.com Cc: K Prateek Nayak kprateek.nayak@amd.com Cc: Ravi Bangoria ravi.bangoria@amd.com Cc: Sandipan Das sandipan.das@amd.com Cc: Anshuman Khandual anshuman.khandual@arm.com Cc: German Gomez german.gomez@arm.com Cc: James Clark james.clark@arm.com Cc: Nick Terrell terrelln@fb.com Cc: Sean Christopherson seanjc@google.com Cc: Changbin Du changbin.du@huawei.com Cc: liuwenyu liuwenyu7@huawei.com Cc: Yang Jihong yangjihong1@huawei.com Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Miguel Ojeda ojeda@kernel.org Cc: Song Liu song@kernel.org Cc: Leo Yan leo.yan@linaro.org Cc: Kajol Jain kjain@linux.ibm.com Cc: Andi Kleen ak@linux.intel.com Cc: Kan Liang kan.liang@linux.intel.com Cc: Athira Rajeev atrajeev@linux.vnet.ibm.com Cc: Yanteng Si siyanteng@loongson.cn Cc: Liam Howlett liam.howlett@oracle.com Cc: Paolo Bonzini pbonzini@redhat.com Link: https://lore.kernel.org/r/20231024222353.3024098-3-irogers@google.com Signed-off-by: Namhyung Kim namhyung@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/util/machine.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 88f31b3a63acb..e6a8d758f6fe4 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -2624,16 +2624,18 @@ static int lbr_callchain_add_lbr_ip(struct thread *thread, save_lbr_cursor_node(thread, cursor, i); }
- /* Add LBR ip from first entries.to */ - ip = entries[0].to; - flags = &entries[0].flags; - *branch_from = entries[0].from; - err = add_callchain_ip(thread, cursor, parent, - root_al, &cpumode, ip, - true, flags, NULL, - *branch_from); - if (err) - return err; + if (lbr_nr > 0) { + /* Add LBR ip from first entries.to */ + ip = entries[0].to; + flags = &entries[0].flags; + *branch_from = entries[0].from; + err = add_callchain_ip(thread, cursor, parent, + root_al, &cpumode, ip, + true, flags, NULL, + *branch_from); + if (err) + return err; + }
return 0; }