--- /dev/null
+From 3f3325fba1a83235a9d56e20a0e72c25c85416b3 Mon Sep 17 00:00:00 2001
+From: Milian Wolff <milian.wolff@kdab.com>
+Date: Mon, 29 Oct 2018 15:16:44 +0100
+Subject: perf unwind: Take pgoff into account when reporting elf to libdwfl
+
+[ Upstream commit 1fe627da30331024f453faef04d500079b901107 ]
+
+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<mutex> guard(g_mutex);
+ uniform_real_distribution<double> uniform(-1E5, 1E5);
+ default_random_engine engine;
+ double s = 0;
+ for (int i = 0; i < 1000; ++i) {
+ s += norm(complex<double>(uniform(engine), uniform(engine)));
+ }
+ cout << s << endl;
+ return s;
+}
+
+int main()
+{
+ vector<std::future<double>> 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<char, std::char_traits<char> >::sputn(char const*, long)+0x1cd (inlined)
+ 7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> >::_M_put(char const*, long)+0x1cd (inlined)
+ 7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> > std::__write<char>(std::ostreambuf_iterator<char, std::char_traits<char> >, char const*, int)+0x1cd (inlined)
+ 7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> > std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::_M_insert_float<double>(std::ostreambuf_iterator<c>
+ 7f38e464bd70 std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::put(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, double) const+0x90 (inl>
+ 7f38e464bd70 std::ostream& std::ostream::_M_insert<double>(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<double, double (*)()>(std::__invoke_other, double (*&&)())+0x2b (inlined)
+ 563b9cb506fb std::__invoke_result<double (*)()>::type std::__invoke<double (*)()>(double (*&&)())+0x2b (inlined)
+ 563b9cb506fb decltype (__invoke((_S_declval<0ul>)())) std::thread::_Invoker<std::tuple<double (*)()> >::_M_invoke<0ul>(std::_Index_tuple<0ul>)+0x2b (inlined)
+ 563b9cb506fb std::thread::_Invoker<std::tuple<double (*)()> >::operator()()+0x2b (inlined)
+ 563b9cb506fb std::__future_base::_Task_setter<std::unique_ptr<std::__future_base::_Result<double>, std::__future_base::_Result_base::_Deleter>, std::thread::_Invoker<std::tuple<double (*)()> >, dou>
+ 563b9cb506fb std::_Function_handler<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> (), std::__future_base::_Task_setter<std::unique_ptr<std::__future_>
+ 563b9cb507e8 std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>::operator()() const+0x28 (inlined)
+ 563b9cb507e8 std::__future_base::_State_baseV2::_M_do_set(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, 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<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*)>
+ 563b9cb51149 std::__future_base::_State_baseV2::_M_set_result(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>, bool)+0xe9 (inlined)
+ 563b9cb51149 std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread::_Invoker<std::tuple<double (*)()> >&&)::{lambda()#1}::op>
+ 563b9cb51149 void std::__invoke_impl<void, std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread::_Invoker<std::tuple<double>
+ 563b9cb51149 std::__invoke_result<std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread::_Invoker<std::tuple<double (*)()> >>
+ 563b9cb51149 decltype (__invoke((_S_declval<0ul>)())) std::thread::_Invoker<std::tuple<std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_>
+ 563b9cb51149 std::thread::_Invoker<std::tuple<std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread::_Invoker<std::tuple<dou>
+ 563b9cb51149 std::thread::_State_impl<std::thread::_Invoker<std::tuple<std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, 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<char, std::char_traits<char> >::sputn(char const*, long)+0x1cd (inlined)
+ 7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> >::_M_put(char const*, long)+0x1cd (inlined)
+ 7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> > std::__write<char>(std::ostreambuf_iterator<char, std::char_traits<char> >, char const*, int)+0x1cd (inlined)
+ 7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> > std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::_M_insert_float<double>(std::ostreambuf_iterator<c>
+ 7f38e464bd70 std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::put(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, double) const+0x90 (inl>
+ 7f38e464bd70 std::ostream& std::ostream::_M_insert<double>(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 <milian.wolff@kdab.com>
+Acked-by: Jiri Olsa <jolsa@kernel.org>
+Link: http://lkml.kernel.org/r/20181029141644.3907-1-milian.wolff@kdab.com
+Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ tools/perf/util/unwind-libdw.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c
+index 8e969f28cc59..f1fe5acdbba4 100644
+--- a/tools/perf/util/unwind-libdw.c
++++ b/tools/perf/util/unwind-libdw.c
+@@ -44,13 +44,13 @@ static int __report_module(struct addr_location *al, u64 ip,
+ Dwarf_Addr s;
+
+ dwfl_module_info(mod, NULL, &s, NULL, NULL, NULL, NULL, NULL);
+- if (s != al->map->start)
++ if (s != al->map->start - al->map->pgoff)
+ mod = 0;
+ }
+
+ if (!mod)
+ mod = dwfl_report_elf(ui->dwfl, dso->short_name,
+- (dso->symsrc_filename ? dso->symsrc_filename : dso->long_name), -1, al->map->start,
++ (dso->symsrc_filename ? dso->symsrc_filename : dso->long_name), -1, al->map->start - al->map->pgoff,
+ false);
+
+ return mod && dwfl_addrmodule(ui->dwfl, ip) == mod ? 0 : -1;
+--
+2.19.1
+
--- /dev/null
+From 068966cd0a774e6336ddb5424dd65341320b488b Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Mon, 28 Jan 2019 14:40:49 -0500
+Subject: Revert "seccomp: add a selftest for get_metadata"
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+This reverts commit e65cd9a20343ea90f576c24c38ee85ab6e7d5fec.
+
+Tommi T. Rrantala notes:
+
+ PTRACE_SECCOMP_GET_METADATA was only added in 4.16
+ (26500475ac1b499d8636ff281311d633909f5d20)
+
+ And it's also breaking seccomp_bpf.c compilation for me:
+
+ seccomp_bpf.c: In function ‘get_metadata’:
+ seccomp_bpf.c:2878:26: error: storage size of ‘md’ isn’t known
+ struct seccomp_metadata md;
+
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ tools/testing/selftests/seccomp/seccomp_bpf.c | 61 -------------------
+ 1 file changed, 61 deletions(-)
+
+diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
+index e350cf3d4f90..194759ec9e70 100644
+--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
++++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
+@@ -145,15 +145,6 @@ struct seccomp_data {
+ #define SECCOMP_FILTER_FLAG_SPEC_ALLOW (1UL << 2)
+ #endif
+
+-#ifndef PTRACE_SECCOMP_GET_METADATA
+-#define PTRACE_SECCOMP_GET_METADATA 0x420d
+-
+-struct seccomp_metadata {
+- __u64 filter_off; /* Input: which filter */
+- __u64 flags; /* Output: filter's flags */
+-};
+-#endif
+-
+ #ifndef seccomp
+ int seccomp(unsigned int op, unsigned int flags, void *args)
+ {
+@@ -2870,58 +2861,6 @@ TEST(get_action_avail)
+ EXPECT_EQ(errno, EOPNOTSUPP);
+ }
+
+-TEST(get_metadata)
+-{
+- pid_t pid;
+- int pipefd[2];
+- char buf;
+- struct seccomp_metadata md;
+-
+- ASSERT_EQ(0, pipe(pipefd));
+-
+- pid = fork();
+- ASSERT_GE(pid, 0);
+- if (pid == 0) {
+- struct sock_filter filter[] = {
+- BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
+- };
+- struct sock_fprog prog = {
+- .len = (unsigned short)ARRAY_SIZE(filter),
+- .filter = filter,
+- };
+-
+- /* one with log, one without */
+- ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER,
+- SECCOMP_FILTER_FLAG_LOG, &prog));
+- ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog));
+-
+- ASSERT_EQ(0, close(pipefd[0]));
+- ASSERT_EQ(1, write(pipefd[1], "1", 1));
+- ASSERT_EQ(0, close(pipefd[1]));
+-
+- while (1)
+- sleep(100);
+- }
+-
+- ASSERT_EQ(0, close(pipefd[1]));
+- ASSERT_EQ(1, read(pipefd[0], &buf, 1));
+-
+- ASSERT_EQ(0, ptrace(PTRACE_ATTACH, pid));
+- ASSERT_EQ(pid, waitpid(pid, NULL, 0));
+-
+- md.filter_off = 0;
+- ASSERT_EQ(sizeof(md), ptrace(PTRACE_SECCOMP_GET_METADATA, pid, sizeof(md), &md));
+- EXPECT_EQ(md.flags, SECCOMP_FILTER_FLAG_LOG);
+- EXPECT_EQ(md.filter_off, 0);
+-
+- md.filter_off = 1;
+- ASSERT_EQ(sizeof(md), ptrace(PTRACE_SECCOMP_GET_METADATA, pid, sizeof(md), &md));
+- EXPECT_EQ(md.flags, 0);
+- EXPECT_EQ(md.filter_off, 1);
+-
+- ASSERT_EQ(0, kill(pid, SIGKILL));
+-}
+-
+ /*
+ * TODO:
+ * - add microbenchmarks
+--
+2.19.1
+
projects / thirdparty / kernel / stable-queue.git / commitdiff
