Messages in this thread Patch in this message |  | | From | Sandipan Das <> | Subject | [PATCH v2 2/3] perf tools powerpc: Fix crash if callchain is empty | Date | Wed, 18 Apr 2018 16:28:59 +0530 |
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For some cases, the callchain provided by the kernel may be empty. So, the callchain ip filtering code will cause a crash if we do not check whether the struct ip_callchain pointer is NULL before accessing any members.
This can be observed on a powerpc64le system running Fedora 27 as shown below.
# perf record -b -e cycles:u ls # perf report --branch-history perf: Segmentation fault -------- backtrace -------- perf[0x1027615c] linux-vdso64.so.1(__kernel_sigtramp_rt64+0x0)[0x7fff856304d8] perf(arch_skip_callchain_idx+0x44)[0x10257c58] perf[0x1017f2e4] perf(thread__resolve_callchain+0x124)[0x1017ff5c] perf(sample__resolve_callchain+0xf0)[0x10172788] ...
Reported-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com> Signed-off-by: Sandipan Das <sandipan@linux.vnet.ibm.com> --- tools/perf/arch/powerpc/util/skip-callchain-idx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/arch/powerpc/util/skip-callchain-idx.c b/tools/perf/arch/powerpc/util/skip-callchain-idx.c index d3a13f79d3ee..910db8762120 100644 --- a/tools/perf/arch/powerpc/util/skip-callchain-idx.c +++ b/tools/perf/arch/powerpc/util/skip-callchain-idx.c @@ -262,7 +262,7 @@ int arch_skip_callchain_idx(struct thread *thread, struct ip_callchain *chain) int rc; u64 skip_slot = -1; - if (chain->nr < 3) + if (!chain || chain->nr < 3) return skip_slot; rc = check_return_addr(thread, chain->ips[1]); -- 2.14.3
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