MDEV-31642: Upgrade may crash if innodb_log_file_buffering=OFF

recv_log_recover_10_5(): Make reads aligned by 4096 bytes, to avoid
any trouble in case the file was opened in O_DIRECT mode and
the physical block size is larger than 512 bytes.
Because innodb_log_file_size used to be defined in whole megabytes,
reading multiples of 4096 bytes instead of 512 should not be an issue.

mysql-test/suite/innodb/t/log_corruption.test

@@ -591,11 +591,11 @@ print OUT pack("x[470]N", 0x677700cf);
 # invalid (all-zero) checkpoint page 1 and an empty log page
 print OUT chr(0) x 1024;
 # valid checkpoint block 2
-print OUT pack("x[12]NNNx[264]", 0x12860c, 0, 0x80c);
+print OUT pack("x[12]NNNx[264]", 0x12860c, 0, 0x120c);
 # pointer to the FILE_CHECKPOINT record, and checkpoint page checksum
-print OUT pack("H*x[204]NNN", "590DBAACFE922582", 0x128612, 0, 0x101741b);
+print OUT pack("H*x[204]NNN", "590DBAACFE922582", 0x128612, 0, 0x3b4ce62d);
 # log page
-print OUT pack("NnnNx[496]N", 0x80000944, 12, 12, 1, 0x46c8a2a2);
+print OUT pack("x[2560]NnnNx[496]N", 0x80000944, 12, 12, 1, 0x46c8a2a2);
 close OUT or die;
 EOF
 

storage/innobase/log/log0recv.cc

@@ -1639,7 +1639,10 @@ static dberr_t recv_log_recover_10_5(lsn_t lsn_offset)
   if (lsn_offset < (log_sys.is_pmem() ? log_sys.file_size : 4096))
     memcpy_aligned<512>(buf, &log_sys.buf[lsn_offset & ~511], 512);
   else
-    recv_sys.read(lsn_offset & ~lsn_t{511}, {buf, 512});
+  {
+    recv_sys.read(lsn_offset & ~lsn_t{4095}, {buf, 4096});
+    buf+= lsn_offset & 0xe00;
+  }
 
   if (!recv_check_log_block(buf))
   {
@@ -1757,7 +1760,7 @@ dberr_t recv_sys_t::find_checkpoint()
     if (dberr_t err= recv_log_recover_pre_10_2())
       return err;
   upgrade:
-    memset_aligned<512>(const_cast<byte*>(field_ref_zero), 0, 512);
+    memset_aligned<4096>(const_cast<byte*>(field_ref_zero), 0, 4096);
     /* Mark the redo log for upgrading. */
     log_sys.last_checkpoint_lsn= log_sys.next_checkpoint_lsn;
     log_sys.set_recovered_lsn(log_sys.next_checkpoint_lsn);