Merge bitcoin/bitcoin#26477: validation: fix broken maxtipage comparison

e4be0e9b0661a8af49c4e6d5472804913f04b8fc test: add -maxtipage test for the maximum allowable value (James O'Beirne)
a451e832b46bcb984dfcd9478ea8ebb8b3de0c62 fix: validation: cast now() to seconds for maxtipage comparison (James O'Beirne)

Pull request description:

  Since https://github.com/bitcoin/bitcoin/commit/faf44876db555f7488c8df96db9fa88b793f897c, the maxtipage comparison in IsInitialBlockDownload() has been broken, since the NodeClock::now() time_point is in the system's native denomination (nanoseconds).

  Without this patch, specifying the maximum allowable -maxtipage (9223372036854775807) results in a SIGABRT crash:

  ```
  % gdb --args ./src/bitcoind -maxtipage=9223372036854775207 -minimumchainwork=0x00 -stopatheight=30000
  ...
  2022-11-09T15:55:17Z [dnsseed] dnsseed thread exit
  [Thread 0x7fff937fe640 (LWP 69883) exited]

  Thread 29 "b-msghand" received signal SIGABRT, Aborted.
  [Switching to Thread 0x7fff91ffb640 (LWP 69886)]
  __pthread_kill_implementation (threadid=<optimized out>, signo=signo@entry=6, no_tid=no_tid@entry=0) at ./nptl/pthread_kill.c:44
  44      ./nptl/pthread_kill.c: No such file or directory.
  (gdb) bt
  #0  __pthread_kill_implementation (threadid=<optimized out>, signo=signo@entry=6, no_tid=no_tid@entry=0) at ./nptl/pthread_kill.c:44
  #1  0x00007ffff768989f in __pthread_kill_internal (signo=6, threadid=<optimized out>) at ./nptl/pthread_kill.c:78
  #2  0x00007ffff763da52 in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/raise.c:26
  #3  0x00007ffff7628469 in __GI_abort () at ./stdlib/abort.c:79
  #4  0x00007ffff7cf79a4 in __mulvdi3 () from /lib/x86_64-linux-gnu/libgcc_s.so.1
  #5  0x00005555558d13ab in std::chrono::__duration_cast_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> >, std::ratio<1000000000l, 1l>, long, false, true>::__cast<long, std::ratio<1l, 1l> > (__d=...) at /usr/include/c++/12/bits/chrono.h:521
  #6  std::chrono::duration_cast<std::chrono::duration<long, std::ratio<1l, 1000000000l> >, long, std::ratio<1l, 1l> > (__d=...)
      at /usr/include/c++/12/bits/chrono.h:260
  #7  std::chrono::duration<long, std::ratio<1l, 1000000000l> >::duration<long, std::ratio<1l, 1l>, void> (__d=..., this=<optimized out>)
      at /usr/include/c++/12/bits/chrono.h:514
  #8  std::chrono::operator-<long, std::ratio<1l, 1000000000l>, long, std::ratio<1l, 1l> > (__rhs=..., __lhs=...)
      at /usr/include/c++/12/bits/chrono.h:650
  #9  std::chrono::operator-<NodeClock, std::chrono::duration<long, std::ratio<1l, 1000000000l> >, long, std::ratio<1l, 1l> > (__rhs=...,
      __lhs=...) at /usr/include/c++/12/bits/chrono.h:1020
  #10 Chainstate::IsInitialBlockDownload (this=0x555556071940) at ./src/validation.cpp:1545
  #11 0x00005555556efd1e in operator() (__closure=<optimized out>) at ./src/net_processing.cpp:3369
  #12 (anonymous namespace)::PeerManagerImpl::ProcessMessage (this=0x555556219be0, pfrom=..., msg_type=..., vRecv=..., time_received=...,
      interruptMsgProc=...) at ./src/net_processing.cpp:3369
  #13 0x00005555556f75cc in (anonymous namespace)::PeerManagerImpl::ProcessMessages (this=0x555556219be0, pfrom=<optimized out>,
      interruptMsgProc=std::atomic<bool> = { false }) at ./src/net_processing.cpp:4985
  #14 0x00005555556a83c9 in CConnman::ThreadMessageHandler (this=0x5555560ebc70) at ./src/net.cpp:2014
  #15 0x0000555555c4d5d6 in std::function<void ()>::operator()() const (this=0x7fff91ffadb0) at /usr/include/c++/12/bits/std_function.h:591
  #16 util::TraceThread(std::basic_string_view<char, std::char_traits<char> >, std::function<void ()>) (
      thread_name="0\255\377\221\377\177\000\000\v\000\000\000\000\000\000\000TraceThread\000\000\000\000\000P\255\377\221\377\177\000\000\017\000\000\000\000\000\000\000util/thread.cpp\000\000\000\000\000\000\000\000\000\000ihB鵿6\000\000\000\000\000\000\000\000\260\255\377\221\377\177\000\000\277\211\321UUU\000\000p\324\304UUU\000\000\002\000\000\000\000\000\000\000\240xh\367\377\177\000\000\000\000\000\000\000\000\000\000]\340iUUU\000\000p\274\016VUU\000\000\000\000\000\000\000\000\000\000\300\303iUUU\000\000p\206jUUU", '\000' <repeats 11 times>, "ihB鵿6\200\251!VUU\000\000"..., thread_func=...) at util/thread.cpp:21
  #17 0x000055555569e05d in std::__invoke_impl<void, void (*)(std::basic_string_view<char>, std::function<void()>), char const*, CConnman::Start(CScheduler&, const Options&)::<lambda()> > (__f=<optimized out>) at /usr/include/c++/12/bits/invoke.h:61
  #18 std::__invoke<void (*)(std::basic_string_view<char>, std::function<void()>), char const*, CConnman::Start(CScheduler&, const Options&)::<lambda()> > (__fn=<optimized out>) at /usr/include/c++/12/bits/invoke.h:96
  #19 std::thread::_Invoker<std::tuple<void (*)(std::basic_string_view<char, std::char_traits<char> >, std::function<void()>), char const*, CConnman::Start(CScheduler&, const Options&)::<lambda()> > >::_M_invoke<0, 1, 2> (this=<optimized out>) at /usr/include/c++/12/bits/std_thread.h:252
  #20 std::thread::_Invoker<std::tuple<void (*)(std::basic_string_view<char, std::char_traits<char> >, std::function<void()>), char const*, CConnman::Start(CScheduler&, const Options&)::<lambda()> > >::operator() (this=<optimized out>) at /usr/include/c++/12/bits/std_thread.h:259
  #21 std::thread::_State_impl<std::thread::_Invoker<std::tuple<void (*)(std::basic_string_view<char, std::char_traits<char> >, std::function<void()>), char const*, CConnman::Start(CScheduler&, const Options&)::<lambda()> > > >::_M_run(void) (this=<optimized out>)
      at /usr/include/c++/12/bits/std_thread.h:210
  #22 0x00007ffff7ad43d3 in ?? () from /lib/x86_64-linux-gnu/libstdc++.so.6
  #23 0x00007ffff7687b27 in start_thread (arg=<optimized out>) at ./nptl/pthread_create.c:435
  #24 0x00007ffff770a78c in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
  (gdb)
  ```

ACKs for top commit:
  MarcoFalke:
    review ACK e4be0e9b0661a8af49c4e6d5472804913f04b8fc 🏽

Tree-SHA512: d892d6264a284d952a68a8631a6301277373b8df939dafd9e2652f2f22ab60712cde63b90c27c67ea2d05f02443452e3e4e1b9f25479bfaca00d4c4de13b9fbd

2 files changed, 15 insertions, 10 deletions

diff --git a/src/validation.cpp b/src/validation.cpp
index d7017248fc..76bea97341 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -1542,7 +1542,7 @@ bool Chainstate::IsInitialBlockDownload() const
     if (m_chain.Tip()->nChainWork < m_chainman.MinimumChainWork()) {
         return true;
     }
-    if (m_chain.Tip()->Time() < NodeClock::now() - m_chainman.m_options.max_tip_age) {
+    if (m_chain.Tip()->Time() < Now<NodeSeconds>() - m_chainman.m_options.max_tip_age) {
         return true;
     }
     LogPrintf("Leaving InitialBlockDownload (latching to false)\n");
diff --git a/test/functional/feature_maxtipage.py b/test/functional/feature_maxtipage.py
index ddc2102542..51f37ef1e0 100755
--- a/test/functional/feature_maxtipage.py
+++ b/test/functional/feature_maxtipage.py
@@ -22,23 +22,24 @@ class MaxTipAgeTest(BitcoinTestFramework):
         self.setup_clean_chain = True
         self.num_nodes = 2
 
-    def test_maxtipage(self, maxtipage, set_parameter=True):
+    def test_maxtipage(self, maxtipage, set_parameter=True, test_deltas=True):
         node_miner = self.nodes[0]
         node_ibd = self.nodes[1]
 
         self.restart_node(1, [f'-maxtipage={maxtipage}'] if set_parameter else None)
         self.connect_nodes(0, 1)
-
-        # tips older than maximum age -> stay in IBD
         cur_time = int(time.time())
-        node_ibd.setmocktime(cur_time)
-        for delta in [5, 4, 3, 2, 1]:
-            node_miner.setmocktime(cur_time - maxtipage - delta)
-            self.generate(node_miner, 1)
-            assert_equal(node_ibd.getblockchaininfo()['initialblockdownload'], True)
+
+        if test_deltas:
+            # tips older than maximum age -> stay in IBD
+            node_ibd.setmocktime(cur_time)
+            for delta in [5, 4, 3, 2, 1]:
+                node_miner.setmocktime(cur_time - maxtipage - delta)
+                self.generate(node_miner, 1)
+                assert_equal(node_ibd.getblockchaininfo()['initialblockdownload'], True)
 
         # tip within maximum age -> leave IBD
-        node_miner.setmocktime(cur_time - maxtipage)
+        node_miner.setmocktime(max(cur_time - maxtipage, 0))
         self.generate(node_miner, 1)
         assert_equal(node_ibd.getblockchaininfo()['initialblockdownload'], False)
 
@@ -51,6 +52,10 @@ class MaxTipAgeTest(BitcoinTestFramework):
             self.log.info(f"Test IBD with maximum tip age of {hours} hours (-maxtipage={maxtipage}).")
             self.test_maxtipage(maxtipage)
 
+        max_long_val = 9223372036854775807
+        self.log.info(f"Test IBD with highest allowable maximum tip age ({max_long_val}).")
+        self.test_maxtipage(max_long_val, test_deltas=False)
+
 
 if __name__ == '__main__':
     MaxTipAgeTest().main()