From 174877f1e344812f620fd8891af97104d5dfca13 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Fri, 25 Mar 2022 14:23:26 -0400 Subject: [PATCH] Harden TAP tests that intentionally corrupt page checksums. The previous method for doing that was to write zeroes into a predetermined set of page locations. However, there's a roughly 1-in-64K chance that the existing checksum will match by chance, and yesterday several buildfarm animals started to reproducibly see that, resulting in test failures because no checksum mismatch was reported. Since the checksum includes the page LSN, test success depends on the length of the installation's WAL history, which is affected by (at least) the initial catalog contents, the set of locales installed on the system, and the length of the pathname of the test directory. Sooner or later we were going to hit a chance match, and today is that day. Harden these tests by specifically inverting the checksum field and leaving all else alone, thereby guaranteeing that the checksum is incorrect. In passing, fix places that were using seek() to set up for syswrite(), a combination that the Perl docs very explicitly warn against. We've probably escaped problems because no regular buffered I/O is done on these filehandles; but if it ever breaks, we wouldn't deserve or get much sympathy. Although we've only seen problems in HEAD, now that we recognize the environmental dependencies it seems like it might be just a matter of time until someone manages to hit this in back-branch testing. Hence, back-patch to v11 where we started doing this kind of test. Discussion: https://postgr.es/m/3192026.1648185780@sss.pgh.pa.us --- contrib/amcheck/t/001_verify_heapam.pl | 5 ++- src/bin/pg_amcheck/t/003_check.pl | 5 ++- src/bin/pg_amcheck/t/004_verify_heapam.pl | 9 +++--- src/bin/pg_basebackup/t/010_pg_basebackup.pl | 34 +++++++------------- src/bin/pg_checksums/t/002_actions.pl | 10 ++---- src/test/perl/PostgreSQL/Test/Cluster.pm | 31 ++++++++++++++++++ 6 files changed, 52 insertions(+), 42 deletions(-) diff --git a/contrib/amcheck/t/001_verify_heapam.pl b/contrib/amcheck/t/001_verify_heapam.pl index bb0997cd5d..019eed33a0 100644 --- a/contrib/amcheck/t/001_verify_heapam.pl +++ b/contrib/amcheck/t/001_verify_heapam.pl @@ -7,7 +7,6 @@ use warnings; use PostgreSQL::Test::Cluster; use PostgreSQL::Test::Utils; -use Fcntl qw(:seek); use Test::More; my ($node, $result); @@ -193,8 +192,8 @@ sub corrupt_first_page # Corrupt some line pointers. The values are chosen to hit the # various line-pointer-corruption checks in verify_heapam.c # on both little-endian and big-endian architectures. - seek($fh, 32, SEEK_SET) - or BAIL_OUT("seek failed: $!"); + sysseek($fh, 32, 0) + or BAIL_OUT("sysseek failed: $!"); syswrite( $fh, pack("L*", diff --git a/src/bin/pg_amcheck/t/003_check.pl b/src/bin/pg_amcheck/t/003_check.pl index d984eacb24..0cf67065d6 100644 --- a/src/bin/pg_amcheck/t/003_check.pl +++ b/src/bin/pg_amcheck/t/003_check.pl @@ -7,7 +7,6 @@ use warnings; use PostgreSQL::Test::Cluster; use PostgreSQL::Test::Utils; -use Fcntl qw(:seek); use Test::More; my ($node, $port, %corrupt_page, %remove_relation); @@ -90,8 +89,8 @@ sub corrupt_first_page # Corrupt some line pointers. The values are chosen to hit the # various line-pointer-corruption checks in verify_heapam.c # on both little-endian and big-endian architectures. - seek($fh, 32, SEEK_SET) - or BAIL_OUT("seek failed: $!"); + sysseek($fh, 32, 0) + or BAIL_OUT("sysseek failed: $!"); syswrite( $fh, pack("L*", diff --git a/src/bin/pg_amcheck/t/004_verify_heapam.pl b/src/bin/pg_amcheck/t/004_verify_heapam.pl index 94d691a614..bbada168f0 100644 --- a/src/bin/pg_amcheck/t/004_verify_heapam.pl +++ b/src/bin/pg_amcheck/t/004_verify_heapam.pl @@ -7,7 +7,6 @@ use warnings; use PostgreSQL::Test::Cluster; use PostgreSQL::Test::Utils; -use Fcntl qw(:seek); use Test::More; # This regression test demonstrates that the pg_amcheck binary correctly @@ -99,8 +98,8 @@ sub read_tuple { my ($fh, $offset) = @_; my ($buffer, %tup); - seek($fh, $offset, SEEK_SET) - or BAIL_OUT("seek failed: $!"); + sysseek($fh, $offset, 0) + or BAIL_OUT("sysseek failed: $!"); defined(sysread($fh, $buffer, HEAPTUPLE_PACK_LENGTH)) or BAIL_OUT("sysread failed: $!"); @@ -165,8 +164,8 @@ sub write_tuple $tup->{c_va_header}, $tup->{c_va_vartag}, $tup->{c_va_rawsize}, $tup->{c_va_extinfo}, $tup->{c_va_valueid}, $tup->{c_va_toastrelid}); - seek($fh, $offset, SEEK_SET) - or BAIL_OUT("seek failed: $!"); + sysseek($fh, $offset, 0) + or BAIL_OUT("sysseek failed: $!"); defined(syswrite($fh, $buffer, HEAPTUPLE_PACK_LENGTH)) or BAIL_OUT("syswrite failed: $!"); return; diff --git a/src/bin/pg_basebackup/t/010_pg_basebackup.pl b/src/bin/pg_basebackup/t/010_pg_basebackup.pl index 9aa35a16a4..47f3d00ac4 100644 --- a/src/bin/pg_basebackup/t/010_pg_basebackup.pl +++ b/src/bin/pg_basebackup/t/010_pg_basebackup.pl @@ -5,7 +5,6 @@ use strict; use warnings; use File::Basename qw(basename dirname); use File::Path qw(rmtree); -use Fcntl qw(:seek); use PostgreSQL::Test::Cluster; use PostgreSQL::Test::Utils; use Test::More; @@ -56,7 +55,7 @@ if (open my $badchars, '>>', "$tempdir/pgdata/FOO\xe0\xe0\xe0BAR") } $node->set_replication_conf(); -system_or_bail 'pg_ctl', '-D', $pgdata, 'reload'; +$node->reload; $node->command_fails( [ @pg_basebackup_defs, '-D', "$tempdir/backup" ], @@ -706,17 +705,13 @@ my $file_corrupt2 = $node->safe_psql('postgres', q{CREATE TABLE corrupt2 AS SELECT b FROM generate_series(1,2) AS b; ALTER TABLE corrupt2 SET (autovacuum_enabled=false); SELECT pg_relation_filepath('corrupt2')} ); -# set page header and block sizes -my $pageheader_size = 24; +# get block size for corruption steps my $block_size = $node->safe_psql('postgres', 'SHOW block_size;'); # induce corruption -system_or_bail 'pg_ctl', '-D', $pgdata, 'stop'; -open $file, '+<', "$pgdata/$file_corrupt1"; -seek($file, $pageheader_size, SEEK_SET); -syswrite($file, "\0\0\0\0\0\0\0\0\0"); -close $file; -system_or_bail 'pg_ctl', '-D', $pgdata, 'start'; +$node->stop; +$node->corrupt_page_checksum($file_corrupt1, 0); +$node->start; $node->command_checks_all( [ @pg_basebackup_defs, '-D', "$tempdir/backup_corrupt" ], @@ -727,16 +722,12 @@ $node->command_checks_all( rmtree("$tempdir/backup_corrupt"); # induce further corruption in 5 more blocks -system_or_bail 'pg_ctl', '-D', $pgdata, 'stop'; -open $file, '+<', "$pgdata/$file_corrupt1"; +$node->stop; for my $i (1 .. 5) { - my $offset = $pageheader_size + $i * $block_size; - seek($file, $offset, SEEK_SET); - syswrite($file, "\0\0\0\0\0\0\0\0\0"); + $node->corrupt_page_checksum($file_corrupt1, $i * $block_size); } -close $file; -system_or_bail 'pg_ctl', '-D', $pgdata, 'start'; +$node->start; $node->command_checks_all( [ @pg_basebackup_defs, '-D', "$tempdir/backup_corrupt2" ], @@ -747,12 +738,9 @@ $node->command_checks_all( rmtree("$tempdir/backup_corrupt2"); # induce corruption in a second file -system_or_bail 'pg_ctl', '-D', $pgdata, 'stop'; -open $file, '+<', "$pgdata/$file_corrupt2"; -seek($file, $pageheader_size, SEEK_SET); -syswrite($file, "\0\0\0\0\0\0\0\0\0"); -close $file; -system_or_bail 'pg_ctl', '-D', $pgdata, 'start'; +$node->stop; +$node->corrupt_page_checksum($file_corrupt2, 0); +$node->start; $node->command_checks_all( [ @pg_basebackup_defs, '-D', "$tempdir/backup_corrupt3" ], diff --git a/src/bin/pg_checksums/t/002_actions.pl b/src/bin/pg_checksums/t/002_actions.pl index 62c608eaf6..0309cbbaa3 100644 --- a/src/bin/pg_checksums/t/002_actions.pl +++ b/src/bin/pg_checksums/t/002_actions.pl @@ -9,7 +9,6 @@ use warnings; use PostgreSQL::Test::Cluster; use PostgreSQL::Test::Utils; -use Fcntl qw(:seek); use Test::More; @@ -24,6 +23,7 @@ sub check_relation_corruption my $tablespace = shift; my $pgdata = $node->data_dir; + # Create table and discover its filesystem location. $node->safe_psql( 'postgres', "CREATE TABLE $table AS SELECT a FROM generate_series(1,10000) AS a; @@ -37,9 +37,6 @@ sub check_relation_corruption my $relfilenode_corrupted = $node->safe_psql('postgres', "SELECT relfilenode FROM pg_class WHERE relname = '$table';"); - # Set page header and block size - my $pageheader_size = 24; - my $block_size = $node->safe_psql('postgres', 'SHOW block_size;'); $node->stop; # Checksums are correct for single relfilenode as the table is not @@ -54,10 +51,7 @@ sub check_relation_corruption ); # Time to create some corruption - open my $file, '+<', "$pgdata/$file_corrupted"; - seek($file, $pageheader_size, SEEK_SET); - syswrite($file, "\0\0\0\0\0\0\0\0\0"); - close $file; + $node->corrupt_page_checksum($file_corrupted, 0); # Checksum checks on single relfilenode fail $node->command_checks_all( diff --git a/src/test/perl/PostgreSQL/Test/Cluster.pm b/src/test/perl/PostgreSQL/Test/Cluster.pm index 0295731bd0..bee6aacf47 100644 --- a/src/test/perl/PostgreSQL/Test/Cluster.pm +++ b/src/test/perl/PostgreSQL/Test/Cluster.pm @@ -2856,6 +2856,37 @@ sub pg_recvlogical_upto =pod +=item $node->corrupt_page_checksum(self, file, page_offset) + +Intentionally corrupt the checksum field of one page in a file. +The server must be stopped for this to work reliably. + +The file name should be specified relative to the cluster datadir. +page_offset had better be a multiple of the cluster's block size. + +=cut + +sub corrupt_page_checksum +{ + my ($self, $file, $page_offset) = @_; + my $pgdata = $self->data_dir; + my $pageheader; + + open my $fh, '+<', "$pgdata/$file" or die "open($file) failed: $!"; + binmode $fh; + sysseek($fh, $page_offset, 0) or die "sysseek failed: $!"; + sysread($fh, $pageheader, 24) or die "sysread failed: $!"; + # This inverts the pd_checksum field (only); see struct PageHeaderData + $pageheader ^= "\0\0\0\0\0\0\0\0\xff\xff"; + sysseek($fh, $page_offset, 0) or die "sysseek failed: $!"; + syswrite($fh, $pageheader) or die "syswrite failed: $!"; + close $fh; + + return; +} + +=pod + =back =cut