summaryrefslogtreecommitdiff
path: root/lib/dump_stack.c
diff options
context:
space:
mode:
authorSandipan Das <sandipan@linux.ibm.com>2018-07-03 17:35:55 +0530
committerArnaldo Carvalho de Melo <acme@redhat.com>2018-07-24 14:53:11 -0300
commit2a9d5050dc84fa2060f08a52f632976923e0fa7e (patch)
tree680bac781044f066c21bb9e1a119525f302b67b7 /lib/dump_stack.c
parenta7f660d6576a5f4504c8ab4f4956bba03d48bf52 (diff)
perf script: Show correct offsets for DWARF-based unwinding
When perf/data is recorded with the dwarf call-graph option, the callchain shown by 'perf script' still shows the binary offsets of the userspace symbols instead of their virtual addresses. Since the symbol offset calculation is based on using virtual address as the ip, we see incorrect offsets as well. The use of virtual addresses affects the ability to find out the line number in the corresponding source file to which an address maps to as described in commit 67540759151a ("perf unwind: Use addr_location::addr instead of ip for entries"). This has also been addressed by temporarily converting the virtual address to the correponding binary offset so that it can be mapped to the source line number correctly. This is a follow-up for commit 19610184693c ("perf script: Show virtual addresses instead of offsets"). This can be verified on a powerpc64le system running Fedora 27 as shown below: # perf probe -x /usr/lib64/libc-2.26.so -a inet_pton # perf record -e probe_libc:inet_pton --call-graph=dwarf ping -6 -c 1 ::1 Before: # perf report --stdio --no-children -s sym,srcline -g address # Samples: 1 of event 'probe_libc:inet_pton' # Event count (approx.): 1 # # Overhead Symbol Source:Line # ........ .................... ........... # 100.00% [.] __GI___inet_pton inet_pton.c | ---gaih_inet getaddrinfo.c:537 (inlined) __GI_getaddrinfo getaddrinfo.c:2304 (inlined) main ping.c:519 generic_start_main libc-start.c:308 (inlined) __libc_start_main libc-start.c:102 ... # perf script -F comm,ip,sym,symoff,srcline,dso ping 15af28 __GI___inet_pton+0xffff000099160008 (/usr/lib64/libc-2.26.so) libc-2.26.so[ffff80004ca0af28] 10fa53 gaih_inet+0xffff000099160f43 libc-2.26.so[ffff80004c9bfa53] (inlined) 1105b3 __GI_getaddrinfo+0xffff000099160163 libc-2.26.so[ffff80004c9c05b3] (inlined) 2d6f main+0xfffffffd9f1003df (/usr/bin/ping) ping[fffffffecf882d6f] 2369f generic_start_main+0xffff00009916013f libc-2.26.so[ffff80004c8d369f] (inlined) 23897 __libc_start_main+0xffff0000991600b7 (/usr/lib64/libc-2.26.so) libc-2.26.so[ffff80004c8d3897] After: # perf report --stdio --no-children -s sym,srcline -g address # Samples: 1 of event 'probe_libc:inet_pton' # Event count (approx.): 1 # # Overhead Symbol Source:Line # ........ .................... ........... # 100.00% [.] __GI___inet_pton inet_pton.c | ---gaih_inet.constprop.7 getaddrinfo.c:537 getaddrinfo getaddrinfo.c:2304 main ping.c:519 generic_start_main.isra.0 libc-start.c:308 __libc_start_main libc-start.c:102 ... # perf script -F comm,ip,sym,symoff,srcline,dso ping 7fffb38aaf28 __GI___inet_pton+0x8 (/usr/lib64/libc-2.26.so) inet_pton.c:68 7fffb385fa53 gaih_inet.constprop.7+0xf43 (/usr/lib64/libc-2.26.so) getaddrinfo.c:537 7fffb38605b3 getaddrinfo+0x163 (/usr/lib64/libc-2.26.so) getaddrinfo.c:2304 130782d6f main+0x3df (/usr/bin/ping) ping.c:519 7fffb377369f generic_start_main.isra.0+0x13f (/usr/lib64/libc-2.26.so) libc-start.c:308 7fffb3773897 __libc_start_main+0xb7 (/usr/lib64/libc-2.26.so) libc-start.c:102 Signed-off-by: Sandipan Das <sandipan@linux.ibm.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Milian Wolff <milian.wolff@kdab.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Fixes: 67540759151a ("perf unwind: Use addr_location::addr instead of ip for entries") Link: http://lkml.kernel.org/r/20180703120555.32971-1-sandipan@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'lib/dump_stack.c')
0 files changed, 0 insertions, 0 deletions