diff options
author | Laurent Pinchart <laurent.pinchart@ideasonboard.com> | 2021-09-24 05:05:51 +0300 |
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committer | Laurent Pinchart <laurent.pinchart@ideasonboard.com> | 2021-10-15 05:05:23 +0300 |
commit | f8d76fe79b6137d3996f951568b29a615bb3c415 (patch) | |
tree | db0e7c4319514f4d188a8809fa321224f745bce7 /src | |
parent | bae9d2bdb32ee8cdc717537ae498eee03a25543b (diff) |
libcamera: base: backtrace: Use libdw to provide symbolic names
libdw provides access to debugging information. This allows creating
better stack trace entries, with file names and line numbers, but also
with demangled symbols as the symbol name is available and can be passed
to abi::__cxa_demangle().
With libdw, the backtrace previously generated by backtrace_symbols()
src/cam/../libcamera/libcamera.so(_ZN9libcamera14VimcCameraData4initEv+0xbd) [0x7f7dbb73222d]
src/cam/../libcamera/libcamera.so(_ZN9libcamera19PipelineHandlerVimc5matchEPNS_16DeviceEnumeratorE+0x3e0) [0x7f7dbb731c40]
src/cam/../libcamera/libcamera.so(_ZN9libcamera13CameraManager7Private22createPipelineHandlersEv+0x1a7) [0x7f7dbb5ea027]
src/cam/../libcamera/libcamera.so(_ZN9libcamera13CameraManager7Private4initEv+0x98) [0x7f7dbb5e9dc8]
src/cam/../libcamera/libcamera.so(_ZN9libcamera13CameraManager7Private3runEv+0x9f) [0x7f7dbb5e9c5f]
src/cam/../libcamera/base/libcamera-base.so(_ZN9libcamera6Thread11startThreadEv+0xee) [0x7f7dbb3e95be]
src/cam/../libcamera/base/libcamera-base.so(+0x4f9d7) [0x7f7dbb3ec9d7]
src/cam/../libcamera/base/libcamera-base.so(+0x4f90e) [0x7f7dbb3ec90e]
src/cam/../libcamera/base/libcamera-base.so(+0x4f2c2) [0x7f7dbb3ec2c2]
/lib64/libpthread.so.0(+0x7e8e) [0x7f7dbab65e8e]
/lib64/libc.so.6(clone+0x3f) [0x7f7dbb10b26f]
becomes
libcamera::VimcCameraData::init()+0xbd (src/libcamera/libcamera.so [0x00007f9de605b22d])
libcamera::PipelineHandlerVimc::match(libcamera::DeviceEnumerator*)+0x3e0 (src/libcamera/libcamera.so [0x00007f9de605ac40])
libcamera::CameraManager::Private::createPipelineHandlers()+0x1a7 (src/libcamera/libcamera.so [0x00007f9de5f13027])
libcamera::CameraManager::Private::init()+0x98 (src/libcamera/libcamera.so [0x00007f9de5f12dc8])
libcamera::CameraManager::Private::run()+0x9f (src/libcamera/libcamera.so [0x00007f9de5f12c5f])
libcamera::Thread::startThread()+0xee (src/libcamera/base/libcamera-base.so [0x00007f9de5d125be])
decltype(*(std::__1::forward<libcamera::Thread*>(fp0)).*fp()) std::__1::__invoke<void (libcamera::Thread::*)(), libcamera::Thread*, void>(void (libcamera::Thread::*&&)(), libcamera::Thread*&&)+0x77 (src/libcamera/base/libcamera-base.so [0x00007f9de5d159d7])
void std::__1::__thread_execute<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct> >, void (libcamera::Thread::*)(), libcamera::Thread*, 2ul>(std::__1::tuple<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct> >, void (libcamera::Thread::*)(), libcamera::Thread*>&, std::__1::__tuple_indices<2ul>)+0x3e (src/libcamera/base/libcamera-base.so [0x00007f9de5d1590e])
void* std::__1::__thread_proxy<std::__1::tuple<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct> >, void (libcamera::Thread::*)(), libcamera::Thread*> >(void*)+0x62 (src/libcamera/base/libcamera-base.so [0x00007f9de5d152c2])
start_thread+0xde (/var/tmp/portage/sys-libs/glibc-2.33-r1/work/glibc-2.33/nptl/pthread_create.c:482)
__clone+0x3f (../sysdeps/unix/sysv/linux/x86_64/clone.S:97)
The stack entries related to libcamera are missing source file name and
line information, which will be investigated separately, but this is
still an improvement.
Use libdw when available, falling back to backtrace_symbols() otherwise,
or if libdw fails for any reason.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Diffstat (limited to 'src')
-rw-r--r-- | src/libcamera/base/backtrace.cpp | 120 | ||||
-rw-r--r-- | src/libcamera/base/meson.build | 7 |
2 files changed, 127 insertions, 0 deletions
diff --git a/src/libcamera/base/backtrace.cpp b/src/libcamera/base/backtrace.cpp index c010a7e4..79e4a31f 100644 --- a/src/libcamera/base/backtrace.cpp +++ b/src/libcamera/base/backtrace.cpp @@ -12,9 +12,16 @@ #include <stdlib.h> #endif +#ifdef HAVE_DW +#include <cxxabi.h> +#include <elfutils/libdwfl.h> +#include <unistd.h> +#endif + #include <sstream> #include <libcamera/base/span.h> +#include <libcamera/base/utils.h> /** * \file backtrace.h @@ -23,6 +30,101 @@ namespace libcamera { +namespace { + +#if HAVE_DW +class DwflParser +{ +public: + DwflParser(); + ~DwflParser(); + + bool isValid() const { return valid_; } + std::string stackEntry(const void *ip); + +private: + Dwfl_Callbacks callbacks_; + Dwfl *dwfl_; + bool valid_; +}; + +DwflParser::DwflParser() + : callbacks_({}), dwfl_(nullptr), valid_(false) +{ + callbacks_.find_elf = dwfl_linux_proc_find_elf; + callbacks_.find_debuginfo = dwfl_standard_find_debuginfo; + + dwfl_ = dwfl_begin(&callbacks_); + if (!dwfl_) + return; + + int ret = dwfl_linux_proc_report(dwfl_, getpid()); + if (ret) + return; + + ret = dwfl_report_end(dwfl_, nullptr, nullptr); + if (ret) + return; + + valid_ = true; +} + +DwflParser::~DwflParser() +{ + if (dwfl_) + dwfl_end(dwfl_); +} + +std::string DwflParser::stackEntry(const void *ip) +{ + Dwarf_Addr addr = reinterpret_cast<Dwarf_Addr>(ip); + + Dwfl_Module *module = dwfl_addrmodule(dwfl_, addr); + if (!module) + return std::string(); + + std::ostringstream entry; + + GElf_Off offset; + GElf_Sym sym; + const char *symbol = dwfl_module_addrinfo(module, addr, &offset, &sym, + nullptr, nullptr, nullptr); + if (symbol) { + char *name = abi::__cxa_demangle(symbol, nullptr, nullptr, nullptr); + entry << (name ? name : symbol) << "+0x" << std::hex << offset + << std::dec; + free(name); + } else { + entry << "??? [" << utils::hex(addr) << "]"; + } + + entry << " ("; + + Dwfl_Line *line = dwfl_module_getsrc(module, addr); + if (line) { + const char *filename; + int lineNumber = 0; + + filename = dwfl_lineinfo(line, &addr, &lineNumber, nullptr, + nullptr, nullptr); + + entry << (filename ? filename : "???") << ":" << lineNumber; + } else { + const char *filename = nullptr; + + dwfl_module_info(module, nullptr, nullptr, nullptr, nullptr, + nullptr, &filename, nullptr); + + entry << (filename ? filename : "???") << " [" << utils::hex(addr) << "]"; + } + + entry << ")"; + return entry.str(); +} +#endif /* HAVE_DW */ + +} /* namespace */ + /** * \class Backtrace * \brief Representation of a call stack backtrace @@ -85,6 +187,24 @@ std::string Backtrace::toString(unsigned int skipLevels) const if (backtrace_.size() <= skipLevels) return std::string(); +#if HAVE_DW + DwflParser dwfl; + + if (dwfl.isValid()) { + std::ostringstream msg; + + Span<void *const> trace{ backtrace_ }; + for (const void *ip : trace.subspan(skipLevels)) { + if (ip) + msg << dwfl.stackEntry(ip) << std::endl; + else + msg << "???" << std::endl; + } + + return msg.str(); + } +#endif + #if HAVE_BACKTRACE Span<void *const> trace{ backtrace_ }; trace = trace.subspan(skipLevels); diff --git a/src/libcamera/base/meson.build b/src/libcamera/base/meson.build index fc00296d..4c44b9f5 100644 --- a/src/libcamera/base/meson.build +++ b/src/libcamera/base/meson.build @@ -19,13 +19,20 @@ libcamera_base_sources = files([ 'utils.cpp', ]) +libdw = cc.find_library('libdw', required : false) + if cc.has_header_symbol('execinfo.h', 'backtrace') config_h.set('HAVE_BACKTRACE', 1) endif +if libdw.found() + config_h.set('HAVE_DW', 1) +endif + libcamera_base_deps = [ dependency('threads'), libatomic, + libdw, ] # Internal components must use the libcamera_base_private dependency to enable |