kernel/tools/perf/util/unwind-libdw.c, branch linux-5.2.y

perf tools: Add missing include for symbols.h

2019-02-06T13:00:38Z

Several places were using definitions found in symbols.h but not including it, getting it by sheer luck from some other headers that now are in the process of removing that include because they don't need it or because simply having struct forward declarations is enough, fix it. Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Link: https://lkml.kernel.org/n/tip-xbcvvx296d70kpg9wb0qmeq9@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

pref tools: Add missing map.h includes

2019-02-06T13:00:38Z

Lots of places get the map.h file indirectly, and since we're going to remove it from machine.h, then those need to include it directly, do it now, before we remove that dep. Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Link: https://lkml.kernel.org/n/tip-ob8jehdjda8h5jsrv9dqj9tf@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf unwind: Take pgoff into account when reporting elf to libdwfl

2018-10-31T12:57:50Z

libdwfl parses an ELF file itself and creates mappings for the individual sections. perf on the other hand sees raw mmap events which represent individual sections. When we encounter an address pointing into a mapping with pgoff != 0, we must take that into account and report the file at the non-offset base address. This fixes unwinding with libdwfl in some cases. E.g. for a file like: ``` using namespace std; mutex g_mutex; double worker() { lock_guard guard(g_mutex); uniform_real_distribution uniform(-1E5, 1E5); default_random_engine engine; double s = 0; for (int i = 0; i < 1000; ++i) { s += norm(complex(uniform(engine), uniform(engine))); } cout << s << endl; return s; } int main() { vector> results; for (int i = 0; i < 10000; ++i) { results.push_back(async(launch::async, worker)); } return 0; } ``` Compile it with `g++ -g -O2 -lpthread cpp-locking.cpp -o cpp-locking`, then record it with `perf record --call-graph dwarf -e sched:sched_switch`. When you analyze it with `perf script` and libunwind, you should see: ``` cpp-locking 20038 [005] 54830.236589: sched:sched_switch: prev_comm=cpp-locking prev_pid=20038 prev_prio=120 prev_state=T ==> next_comm=swapper/5 next_pid=0 next_prio=120 ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb1670208 schedule+0x28 (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb16737cc rwsem_down_read_failed+0xec (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb1665e04 call_rwsem_down_read_failed+0x14 (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb1672a03 down_read+0x13 (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb106bd85 __do_page_fault+0x445 (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb18015f5 page_fault+0x45 (/lib/modules/4.14.78-1-lts/build/vmlinux) 7f38e4252591 new_heap+0x101 (/usr/lib/libc-2.28.so) 7f38e4252d0b arena_get2.part.4+0x2fb (/usr/lib/libc-2.28.so) 7f38e4255b1c tcache_init.part.6+0xec (/usr/lib/libc-2.28.so) 7f38e42569e5 __GI___libc_malloc+0x115 (inlined) 7f38e4241790 __GI__IO_file_doallocate+0x90 (inlined) 7f38e424fbbf __GI__IO_doallocbuf+0x4f (inlined) 7f38e424ee47 __GI__IO_file_overflow+0x197 (inlined) 7f38e424df36 _IO_new_file_xsputn+0x116 (inlined) 7f38e4242bfb __GI__IO_fwrite+0xdb (inlined) 7f38e463fa6d std::basic_streambuf >::sputn(char const*, long)+0x1cd (inlined) 7f38e463fa6d std::ostreambuf_iterator >::_M_put(char const*, long)+0x1cd (inlined) 7f38e463fa6d std::ostreambuf_iterator > std::__write(std::ostreambuf_iterator >, char const*, int)+0x1cd (inlined) 7f38e463fa6d std::ostreambuf_iterator > std::num_put > >::_M_insert_float(std::ostreambuf_iterator 7f38e464bd70 std::num_put > >::put(std::ostreambuf_iterator >, std::ios_base&, char, double) const+0x90 (inl> 7f38e464bd70 std::ostream& std::ostream::_M_insert(double)+0x90 (/usr/lib/libstdc++.so.6.0.25) 563b9cb502f7 std::ostream::operator<<(double)+0xb7 (inlined) 563b9cb502f7 worker()+0xb7 (/ssd/milian/projects/kdab/rnd/hotspot/build/tests/test-clients/cpp-locking/cpp-locking) 563b9cb506fb double std::__invoke_impl(std::__invoke_other, double (*&&)())+0x2b (inlined) 563b9cb506fb std::__invoke_result::type std::__invoke(double (*&&)())+0x2b (inlined) 563b9cb506fb decltype (__invoke((_S_declval<0ul>)())) std::thread::_Invoker >::_M_invoke<0ul>(std::_Index_tuple<0ul>)+0x2b (inlined) 563b9cb506fb std::thread::_Invoker >::operator()()+0x2b (inlined) 563b9cb506fb std::__future_base::_Task_setter, std::__future_base::_Result_base::_Deleter>, std::thread::_Invoker >, dou> 563b9cb506fb std::_Function_handler (), std::__future_base::_Task_setter 563b9cb507e8 std::function ()>::operator()() const+0x28 (inlined) 563b9cb507e8 std::__future_base::_State_baseV2::_M_do_set(std::function ()>*, bool*)+0x28 (/ssd/milian/> 7f38e46d24fe __pthread_once_slow+0xbe (/usr/lib/libpthread-2.28.so) 563b9cb51149 __gthread_once+0xe9 (inlined) 563b9cb51149 void std::call_once ()>*, bool*)> 563b9cb51149 std::__future_base::_State_baseV2::_M_set_result(std::function ()>, bool)+0xe9 (inlined) 563b9cb51149 std::__future_base::_Async_state_impl >, double>::_Async_state_impl(std::thread::_Invoker >&&)::{lambda()#1}::op> 563b9cb51149 void std::__invoke_impl >, double>::_Async_state_impl(std::thread::_Invoker 563b9cb51149 std::__invoke_result >, double>::_Async_state_impl(std::thread::_Invoker >> 563b9cb51149 decltype (__invoke((_S_declval<0ul>)())) std::thread::_Invoker >, double>::_Async_state_> 563b9cb51149 std::thread::_Invoker >, double>::_Async_state_impl(std::thread::_Invoker 563b9cb51149 std::thread::_State_impl >, double>::_Async_state_impl(std::thread> 7f38e45f0062 execute_native_thread_routine+0x12 (/usr/lib/libstdc++.so.6.0.25) 7f38e46caa9c start_thread+0xfc (/usr/lib/libpthread-2.28.so) 7f38e42ccb22 __GI___clone+0x42 (inlined) ``` Before this patch, using libdwfl, you would see: ``` cpp-locking 20038 [005] 54830.236589: sched:sched_switch: prev_comm=cpp-locking prev_pid=20038 prev_prio=120 prev_state=T ==> next_comm=swapper/5 next_pid=0 next_prio=120 ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb1670208 schedule+0x28 (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb16737cc rwsem_down_read_failed+0xec (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb1665e04 call_rwsem_down_read_failed+0x14 (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb1672a03 down_read+0x13 (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb106bd85 __do_page_fault+0x445 (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb18015f5 page_fault+0x45 (/lib/modules/4.14.78-1-lts/build/vmlinux) 7f38e4252591 new_heap+0x101 (/usr/lib/libc-2.28.so) a041161e77950c5c [unknown] ([unknown]) ``` With this patch applied, we get a bit further in unwinding: ``` cpp-locking 20038 [005] 54830.236589: sched:sched_switch: prev_comm=cpp-locking prev_pid=20038 prev_prio=120 prev_state=T ==> next_comm=swapper/5 next_pid=0 next_prio=120 ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb1670208 schedule+0x28 (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb16737cc rwsem_down_read_failed+0xec (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb1665e04 call_rwsem_down_read_failed+0x14 (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb1672a03 down_read+0x13 (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb106bd85 __do_page_fault+0x445 (/lib/modules/4.14.78-1-lts/build/vmlinux) ffffffffb18015f5 page_fault+0x45 (/lib/modules/4.14.78-1-lts/build/vmlinux) 7f38e4252591 new_heap+0x101 (/usr/lib/libc-2.28.so) 7f38e4252d0b arena_get2.part.4+0x2fb (/usr/lib/libc-2.28.so) 7f38e4255b1c tcache_init.part.6+0xec (/usr/lib/libc-2.28.so) 7f38e42569e5 __GI___libc_malloc+0x115 (inlined) 7f38e4241790 __GI__IO_file_doallocate+0x90 (inlined) 7f38e424fbbf __GI__IO_doallocbuf+0x4f (inlined) 7f38e424ee47 __GI__IO_file_overflow+0x197 (inlined) 7f38e424df36 _IO_new_file_xsputn+0x116 (inlined) 7f38e4242bfb __GI__IO_fwrite+0xdb (inlined) 7f38e463fa6d std::basic_streambuf >::sputn(char const*, long)+0x1cd (inlined) 7f38e463fa6d std::ostreambuf_iterator >::_M_put(char const*, long)+0x1cd (inlined) 7f38e463fa6d std::ostreambuf_iterator > std::__write(std::ostreambuf_iterator >, char const*, int)+0x1cd (inlined) 7f38e463fa6d std::ostreambuf_iterator > std::num_put > >::_M_insert_float(std::ostreambuf_iterator 7f38e464bd70 std::num_put > >::put(std::ostreambuf_iterator >, std::ios_base&, char, double) const+0x90 (inl> 7f38e464bd70 std::ostream& std::ostream::_M_insert(double)+0x90 (/usr/lib/libstdc++.so.6.0.25) 563b9cb502f7 std::ostream::operator<<(double)+0xb7 (inlined) 563b9cb502f7 worker()+0xb7 (/ssd/milian/projects/kdab/rnd/hotspot/build/tests/test-clients/cpp-locking/cpp-locking) 6eab825c1ee3e4ff [unknown] ([unknown]) ``` Note that the backtrace is still stopping too early, when compared to the nice results obtained via libunwind. It's unclear so far what the reason for that is. Committer note: Further comment by Milian on the thread started on the Link: tag below: --- The remaining issue is due to a bug in elfutils: https://sourceware.org/ml/elfutils-devel/2018-q4/msg00089.html With both patches applied, libunwind and elfutils produce the same output for the above scenario. --- Signed-off-by: Milian Wolff Acked-by: Jiri Olsa Link: http://lkml.kernel.org/r/20181029141644.3907-1-milian.wolff@kdab.com Signed-off-by: Arnaldo Carvalho de Melo

perf script: Show correct offsets for DWARF-based unwinding

2018-07-24T17:53:11Z

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 Acked-by: Jiri Olsa Cc: Milian Wolff Cc: Namhyung Kim Cc: Naveen N. Rao Cc: Ravi Bangoria 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

perf thread: Make thread__find_map() search all maps

2018-04-26T16:47:17Z

We still have the split internally, but users don't see it anymore, simplifying the growing number of cases where we end up searching in the MAP__VARIABLE maps. This further paves the way for ditching the split. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: https://lkml.kernel.org/n/tip-86mfxrztf310konutxvhr5ua@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf thread: Make thread__find_map() return the map

2018-04-26T16:47:08Z

It was returning the searched map just on the addr_location passed, with the function itself returning void. Make it return the map so that we can make the code more compact. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: https://lkml.kernel.org/n/tip-tzlrrzdeoof4i6ktyqv1t6ks@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf thread: Introduce thread__find_symbol()

2018-04-26T16:47:07Z

Out of thread__find_addr_location(..., MAP__FUNCTION, ...), idea here is to continue removing references to MAP__{FUNCTION,VARIABLE} ahead of getting both types of symbols in the same rbtree, as various places do two lookups, looking first at MAP__FUNCTION, then at MAP__VARIABLE. So thread__find_symbol() will eventually do just that, and 'struct symbol' will have the symbol type, for code that cares about that. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: https://lkml.kernel.org/n/tip-n7528en9e08yd3flzmb26tth@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf thread: Introduce thread__find_map()

2018-04-26T16:47:06Z

Out of thread__find_add_map(..., MAP__FUNCTION, ...), idea here is to continue removing references to MAP__{FUNCTION,VARIABLE} ahead of getting both types of symbols in the same rbtree, as various places do two lookups, looking first at MAP__FUNCTION, then at MAP__VARIABLE. So thread__find_map() will eventually do just that, and 'struct symbol' will have the symbol type, for code that cares about that. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: https://lkml.kernel.org/n/tip-q27xee34l4izpfau49w103s6@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf unwind: Report error from dwfl_attach_state

2018-03-20T16:16:09Z

In verbose level 2, errors returned by libdw are reported in most cases, but not when calling dwfl_attach_state. Since elfutils v 0.160 (2014), dwfl_attach_state sets the error code to report failure cause. On failure, log the reported error. Signed-off-by: Martin Vuille Reviewed-by: Kim Phillips Link: http://lkml.kernel.org/r/20180318175053.4222-1-jpmv27@aim.com Signed-off-by: Arnaldo Carvalho de Melo

perf unwind: Unwind with libdw doesn't take symfs into account

2018-03-16T16:55:51Z

Path passed to libdw for unwinding doesn't include symfs path if specified, so unwinding fails because ELF file is not found. Similar to unwinding with libunwind, pass symsrc_filename instead of long_name. If there is no symsrc_filename, fallback to long_name. Signed-off-by: Martin Vuille Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/r/20180211212420.18388-1-jpmv27@aim.com Signed-off-by: Arnaldo Carvalho de Melo